Anthranilamide arthropodicide treatment (2024)

This invention relates to the control of phytophagous invertebrate pests such as arthropod pests by contacting plant propagules or the locus of the propagules with certain anthranilamides and to propagule-coating compositions comprising the anthranilamides.

The control of invertebrate pests such as arthropods is extremely important in achieving high crop efficiency. Damage by invertebrate pests to growing and stored agronomic crops can cause significant reduction in productivity and thereby result in increased costs to the consumer. The control of invertebrate pests in forestry, greenhouse crops, ornamentals and nursery crops is also important.

Plants are subject to injury by invertebrate pests at all stages of growth, beginning with seeds or other propagules such as bulbs, tubers, rhizomes, corms, and stem and leaf cuttings and ending with mature plants. Besides the cost of materials, the effort and time required for application of invertebrate pest control substances make repetition of treatments undesirable. Ideally a single treatment of a plant at the propagule stage would protect the plant from invertebrate pests during its entire life.

A variety of techniques for treating propagules with plant protection substances are known. These include soaking propagules in arthropodicide-comprising solutions, coating propagules with films, pelleting materials and the like comprising arthropodicidal compositions, and applying arthropodicidal compounds to the growing medium surrounding the propagules. While some compounds can effectively protect propagules from certain phytophagous invertebrate pests, new compounds are needed that are more effective or have a broader spectrum of activity, are less costly, less toxic, environmentally safer or have different modes of action.

Particularly needed are invertebrate pest control treatments that can protect the plant not only at its propagule stage but also later in its development. Achieving this objective requires compounds that are active against invertebrate pests and can effectively translocate from the locus of the propagule up through the growing stems, leaves and other aboveground plant parts. Furthermore the compounds need to have high activity against invertebrate pests to compensate for the dilution occasioned by the expanding plant mass. Also, the compounds cannot rapidly degrade and lose their biological potency in the environment of the plant's vascular tissues. The combination of these properties is rare. Treatments of propagules effective for protecting from phytophagous invertebrate pests not only the propagule but also the plant at later growth stages have now been discovered.

wherein

A and B are independently O or S;

R¹ is H, C₁-C₆ alkyl, C₂-C₆ alkoxycarbonyl or C₂-C₆ alkylcarbonyl;

R² is H or C₁-C₆ alkyl;

R³ is H; C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, or C₃-C₆ cycloalkyl, each optionally substituted with one or more substituents selected from the group consisting of halogen, CN, NO₂, hydroxy, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ haloalkoxy, C₁-C₄ alkylthio, C₁-C₄ alkylsulfinyl, C₁-C₄ alkylsulfonyl, C₂-C₆ alkoxycarbonyl, C₂-C₆ alkylcarbonyl, C₃-C₆ trialkylsilyl, phenyl, phenoxy, 5-membered heteroaromatic rings, and 6-membered heteroaromatic rings;

each phenyl, phenoxy, 5-membered heteroaromatic ring, and 6-membered heteroaromatic ring optionally substituted with one to three substituents independently selected from the group consisting of C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₃-C₆ cycloalkyl, C₁-C₄ haloalkyl C₂-C₄ haloalkenyl, C₂-C₄ haloalkynyl, C₃-C₆ halocycloalkyl, halogen, CN, NO₂, C₁-C₄ alkoxy, C₁-C₄ haloalkoxy, C₁-C₄ alkylthio, C₁-C₄ alkylsulfinyl, C₁-C₄ alkylsulfonyl, C₁-C₄ alkylamino, C₂-C₈ dialkylamino, C₃-C₆ cycloalkylamino, C₄-C₈ (alkyl)(cycloalkyl)amino, C₂-C₄ alkylcarbonyl, C₂-C₆ alkoxycarbonyl, C₂-C₆ alkylaminocarbonyl, C₃-C₈ dialkylaminocarbonyl and C₃-C₆ trialkylsilyl; C₁-C₄ alkoxy; C₁-C₄ alkylamino; C₂-C₈ dialkylamino; C₃-C₆ cycloalkylamino; C₂-C₆ alkoxycarbonyl or C₂-C₆ alkylcarbonyl;

R⁴ is H, C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₆ cycloalkyl, C₁-C₆ haloalkyl, CN, halogen, C₁-C₄ alkoxy, C₁-C₄ haloalkoxy or NO₂;

R⁵ is H, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₄ alkoxyalkyl, C₁-C₄ hydroxyalkyl, C(O)R¹⁰, CO₂R¹⁰, C(O)NR¹⁰R¹¹, halogen, C₁-C₄ alkoxy, C₁-C₄ haloalkoxy, NR¹⁰R¹¹, N(R¹¹)C(O)R¹⁰, N(R¹¹)CO₂R¹⁰ or S(O)_nR¹²;

R⁶ is H, C₁-C₆ alkyl, C₁-C₆ haloalkyl, halogen, CN, C₁-C₄ alkoxy or C₁-C₄ haloalkoxy;

R⁷ is C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₃-C₆ cycloalkyl, C₁-C₆ haloalkyl, C₂-C₆ haloalkenyl, C₂-C₆ haloalkynyl or C₃-C₆ halocycloalkyl; or

R⁷ is a phenyl ring, a benzyl ring, a 5- or 6-membered heteroaromatic ring, a naphthyl ring system or an aromatic 8-, 9- or 10-membered fused heterobicyclic ring system, each ring or ring system optionally substituted with one to three substituents independently selected from R⁹;

R⁸ is H, C₁-C₆ alkyl, C₁-C₆ haloalkyl, halogen, C₁-C₄ alkoxy or C₁-C₄ haloalkoxy;

each R⁹ is independently C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₃-C₆ cycloalkyl, C₁-C₄ haloalkyl, C₂-C₄ haloalkenyl, C₂-C₄ haloalkynyl, C₃-C₆ halocycloalkyl, halogen, CN, NO₂, C₁-C₄ alkoxy, C₁-C₄ haloalkoxy, C₁-C₄ alkylthio, C₁-C₄ alkylsulfinyl, C₁-C₄ alkylsulfonyl, C₁-C₄ alkylamino, C₂-C₈ dialkylamino, C₃-C₆ cycloalkylamino, C₄-C₈ (alkyl)(cycloalkyl)amino, C₂-C₄ alkylcarbonyl, C₂-C₆ alkoxycarbonyl, C₂-C₆ alkylaminocarbonyl, C₃-C₈ dialkylaminocarbonyl or C₃-C₆ trialkylsilyl;

R¹⁰ is H, C₁-C₄ alkyl or C₁-C₄ haloalkyl;

R¹¹ is H or C₁-C₄ alkyl;

R¹² is C₁-C₄ alkyl or C₁-C₄ haloalkyl; and

n is 0, 1 or 2.

This invention provides a method for protecting a propagule or a plant grown therefrom from an invertebrate pest. The method comprises contacting the propagule or the locus of the propagule with a biologically effective amount of a compound of Formula I, an N-oxide thereof or an agriculturally suitable salt thereof.

This invention also provides a propagule comprising a biologically effective amount of a compound of Formula I, its N-oxide or an agriculturally suitable salt thereof.

This invention further provides a propagule contacted with a biologically effective amount of a compound of Formula I, its N-oxide or an agriculturally suitable salt thereof.

This invention still further provides an invertebrate pest control composition for coating a propagule comprising a biologically effective amount of a compound of Formula I, its N-oxide or an agriculturally suitable salt thereof and a film former or adhesive agent.

As referred to in the present disclosure and claims, the term “propagule” means a seed or a regenerable plant part. The term “regenerable plant part” means a part of a plant other than a seed from which a whole plant may be grown or regenerated when the plant part is placed in horticultural or agricultural growing media such as moistened soil, peat moss, sand, vermiculite, perlite, rock wool, fiberglass, coconut husk fiber, tree fern fiber and the like, or even a completely liquid medium such as water. Regenerable plant parts commonly include rhizomes, tubers, bulbs and corms of such geophytic plant species as potato, sweet potato, yam, onion, dahlia, tulip, narcissus, etc. Regenerable plant parts include plant parts that are divided (e.g., cut) to preserve their ability to grow into a new plant. Therefore regenerable plant parts include viable divisions of rhizomes, tubers, bulbs and corms which retain meristematic tissue, such as an eye. Regenerable plant parts can also include other plant parts such as cut or separated stems and leaves from which some species of plants can be grown using horticultural or agricultural growing media. As referred to in the present disclosure and claims, unless otherwise indicated, the term “seed” includes both unsprouted seeds and sprouted seeds in which the testa (seed coat) still surrounds part of the emerging shoot and root.

In the above recitations, the term “alkyl”, used either alone or in compound words such as “alkylthio” or “haloalkyl” includes straight-chain or branched alkyl, such as, methyl, ethyl, n-propyl, i-propyl, or the different butyl, pentyl or hexyl isomers. “Alkenyl” includes straight-chain or branched alkenes such as 1-propenyl, 2-propenyl, and the different butenyl, pentenyl and hexenyl isomers. “Alkenyl” also includes polyenes such as 1,2-propadienyl and 2,4-hexadienyl. “Alkynyl” includes straight-chain or branched alkynes such as 1-propynyl, 2-propynyl and the different butynyl, pentynyl and hexynyl isomers. “Alkynyl” can also include moieties comprised of multiple triple bonds such as 2,5-hexadiynyl. “Alkoxy” includes, for example, methoxy, ethoxy, n-propyloxy, isopropyloxy and the different butoxy, pentoxy and hexyloxy isomers. “Alkoxyalkyl” denotes alkoxy substitution on alkyl. Examples of “alkoxyalkyl” include CH₃OCH₂, CH₃OCH₂CH₂, CH₃CH₂OCH₂, CH₃CH₂CH₂CH₂OCH₂ and CH₃CH₂OCH₂CH₂. “Alkylthio”includes branched or straight-chain alkylthio moieties such as methylthio, ethylthio, and the different propylthio, butylthio, pentylthio and hexylthio isomers. “Cycloalkyl” includes, for example, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

The term “heterocyclic ring” or “heterocyclic ring system” denotes rings or ring systems in which at least one ring atom is not carbon and comprises 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, oxygen and sulfur, provided that each heterocyclic ring comprises no more than 4 nitrogens, no more than 2 oxygens and no more than 2 sulfurs. The heterocyclic ring can be attached through any available carbon or nitrogen by replacement of hydrogen on said carbon or nitrogen. The term “aromatic ring system” denotes fully unsaturated carbocycles and heterocycles in which at least one ring of the polycyclic ring system is aromatic (where aromatic indicates that the Hückel rule is satisfied for the ring system). The term “heteroaromatic ring” denotes fully aromatic rings in which at least one ring atom is not carbon and comprises 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, oxygen and sulfur, provided that each heterocyclic ring comprises no more than 4 nitrogens, no more than 2 oxygens and no more than 2 sulfurs (where aromatic indicates that the Hückel rule is satisfied). The heterocyclic ring can be attached through any available carbon or nitrogen by replacement of hydrogen on said carbon or nitrogen. The term “aromatic heterocyclic ring system” includes fully aromatic heterocycles and heterocycles in which at least one ring of a polycyclic ring system is aromatic (where aromatic indicates that the Hückel rule is satisfied). The term “fused heterobicyclic ring system” includes a ring system comprised of two fused rings in which at least one ring atom is not carbon and can be aromatic or non aromatic, as defined above.

The term “halogen”, either alone or in compound words such as “haloalkyl”, includes fluorine, chlorine, bromine or iodine. Further, when used in compound words such as “haloalkyl”, said alkyl may be partially or fully substituted with halogen atoms which may be the same or different. Examples of “haloalkyl” include F₃C, ClCH₂, CF₃CH₂ and CF₃CCl₂. The terms “haloalkenyl”, “haloalkynyl”, “haloalkoxy”, and the like, are defined analogously to the term “haloalkyl”. Examples of “haloalkenyl” include (Cl)₂C═CHCH₂ and CF₃CH₂CH═CHCH₂. Examples of “haloalkynyl” include HC≡CCHCl, CF₃C≡C, CCl₃C≡C and FCH₂C≡CCH₂. Examples of “halo alkoxy” include CF₃O, CCl₃CH₂O, HCF₂CH₂CH₂O and CF₃CH₂O.

The total number of carbon atoms in a substituent group is indicated by the “C_i-C_j” prefix where i and j are numbers from 1 to 8. For example, C₁-C₄ alkylsulfonyl designates methylsulfonyl through butylsulfonyl; C₂ alkoxyalkyl designates CH₃OCH₂; C₃ alkoxyalkyl designates, for example, CH₃CH(OCH₃), CH₃OCH₂CH₂ or CH₃CH₂OCH₂; and C₄ alkoxyalkyl designates the various isomers of an alkyl group substituted with an alkoxy group containing a total of four carbon atoms, examples including CH₃CH₂CH₂OCH₂ and CH₃CH₂OCH₂CH₂. In the above recitations, when a compound of Formula I comprises a heterocyclic ring, all substituents are attached to this ring through any available carbon or nitrogen by replacement of a hydrogen on said carbon or nitrogen.

When a group has a substituent which can be hydrogen, for example R³, then, when this substituent is taken as hydrogen, it is recognized that this is equivalent to said group being unsubstituted.

Compounds of Formula I can exist as one or more stereoisomers. The various stereoisomers include enantiomers, diastereomers, atropisomers and geometric isomers. One skilled in the art will appreciate that one stereoisomer may be more active and/or may exhibit beneficial effects when enriched relative to the other stereoisomer(s) or when separated from the other stereoisomer(s). Additionally, the skilled artisan knows how to separate, enrich, and/or to selectively prepare said stereoisomers. Accordingly, the compounds of the invention may be present as a mixture of stereoisomers, individual stereoisomers, or as an optically active form.

The salts of compounds of Formula I include acid-addition salts with inorganic or organic acids such as hydrobromic, hydrochloric, nitric, phosphoric, sulfuric, acetic, butyric, fumaric, lactic, maleic, malonic, oxalic, propionic, salicylic, tartaric, 4-toluenesulfonic or valeric acids.

Methods, propagules and compositions of the invention preferred for reason of cost, ease of chemical synthesis or application, and/or biological efficacy involve the following preferred compounds:

Preferred 1. A compound of Formula I wherein

A and B are both O;

each ring optionally substituted with one to three substituents independently selected from R⁹;

Q is O, S, NH or NR⁹; and

W, X, Y and Z are independently N, CH or CR⁹, provided that in J-3 and J-4 at least one of W, X, Y or Z is N.

Preferred 2. A compound of Preferred 1 wherein

R¹, R² and R⁸ are all H;

R³ is C₁-C₄ alkyl optionally substituted with halogen, CN, OCH₃ or S(O)_pCH₃;

R⁴ group is attached at position 2;

R⁴ is CH₃, CF₃, OCF₃, OCHF₂, CN or halogen;

R⁵ is H, CH₃ or halogen;

R⁶ is CH₃, CF₃ or halogen;

R⁷ is phenyl or 2-pyridinyl, each optionally substituted; and p is 0, 1 or 2.

Preferred 3. A compound of Preferred 2 wherein R³ is C₁-C₄ alkyl and R⁶ is CF₃.

Preferred 4. A compound of Preferred 2 wherein R³ is C₁-C₄ alkyl and R⁶ is Cl or Br.

The method of Scheme 1 involves coupling of an amine of Formula 2 with an acid chloride of Formula 3 in the presence of an acid scavenger to provide the compound of Formula Ia. Typical acid scavengers include amine bases such as triethylamine, N,N-diisopropylethylamine and pyridine; other scavengers include hydroxides such as sodium and potassium hydroxide and carbonates such as sodium carbonate and potassium carbonate. In certain instances it is useful to use polymer-supported acid scavengers such as polymer-bound [,N-diisopropylethylamine and polymer-bound 4-(dimethylamino)pyridine. The coupling can be run in a suitable inert solvent such as tetrahydrofuran, dioxane, diethylether or dichloromethane to afford the anilide of Formula Ia.

A thioamide of Formula Ib can be obtained in a subsequent step from the corresponding amide of Formula Ia by treatment with one of a variety of standard thio transfer reagents including phosphorus pentasulfide and Lawesson's reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4disulfide).

Polymer-supported reagents are again useful here, such as polymer-bound cyclohexylcarbodiimide. The coupling can be run in a suitable inert solvent such as dichloromethane or N,N-dimethylformamide. The synthetic methods of Schemes 1 and 2 are just representative examples of a wide variety of coupling methods useful for the preparation of Formula I compounds; the synthetic literature is extensive for this type of coupling reaction.

One skilled in the art will also realize that acid chlorides of Formula 3 may be prepared from acids of Formula 4 by numerous well-known methods. For example, acid chlorides of Formula 3 are readily made from carboxylic acids of Formula 4 by reacting the carboxylic acid 4 with thionyl chloride or oxalyl chloride in an inert solvent such as toluene or dichloromethane in the presence of a catalytic amount of N,N-dimethylformamide.

Typical procedures involve reduction with hydrogen in the presence of a metal catalyst such as palladium on carbon or platinum oxide and in hydroxylic solvents such as ethanol and isopropanol. Amines of Formula 2a can also be prepared by reduction with zinc in acetic acid. These procedures are well documented in the chemical literature. R¹ substituents such as C₁-C₆ alkyl can be introduced at this stage through well known methodologies including either direct alkylation or through the generally preferred method of reductive alkylation of the amine. As is further shown in Scheme 3, a commonly employed procedure is to combine the amine 2a with an aldehyde in the presence of a reducing agent such as sodium cyanoborohydride to produce the Formula 2b compounds where R¹ is C₁-C₆ alkyl.

Alkyl chloroformates, such as ethyl chloroformate or isopropyl chloroformate, are especially useful reagents for this type of reaction involving activation of the acid. The chemical literature is extensive regarding methods for amide formation. Amides of Formula 5a are readily converted to thioamides of Formula 5b by using commercially available thio transfer reagents such as phosphorus pentasulfide and Lawesson's reagent.

Typical procedures involve combination of equimolar amounts of the amine 7 with the isatoic anhydride in polar aprotic solvents such as pyridine and N,N-dimethylformamide at temperatures ranging from room temperature to 100° C. R¹ substituents such as alkyl and substituted alkyl may be introduced by the base-catalyzed alkylation of isatoic anhydride 8 with known alkylating reagents R¹-Lg (wherein Lg is a nucleophilic displaceable leaving group such as halide, alkyl or aryl sulfonates or alkyl sulfates) to provide the alkyl substituted intermediate 9. Isatoic anhydrides of Formula 8 may be made by methods described in Coppola, Synthesis 1980, 505-36.

The reaction of Scheme 7 can be run neat or in a variety of suitable solvents including tetrahydrofuran, diethyl ether, pyridine, dichloromethane or chloroform with optimum temperatures ranging from room temperature to the reflux temperature of the solvent. The general reaction of benzoxazinones with amines to produce anthranilamides is well documented in the chemical literature. For a review of benzoxazinone chemistry see Jakobsen et al., Biorganic and Medicinal Chemistry 2000, 8, 2095-2103 and references cited therein. See also Coppola, J. Heterocyclic Chemistry 1999, 36, 563-588.

This involves sequential addition of methanesulfonyl chloride in the presence of a tertiary amine such as triethylamine or pyridine to a pyrazolecarboxylic acid of Formula 4a, followed by the addition of an anthranilic acid of Formula 11, followed by a second addition of tertiary amine and methanesulfonyl chloride. This procedure generally affords good yields of the benzoxazinone and is illustrated with greater detail in Examples 6 and 8.

Solvents such as pyridine or pyridine/acetonitrile are suitable for this reaction. The acid chlorides of Formula 3a are available from the corresponding acids of Formula 4a by a variety of synthetic methods such as chlorination with thionyl chloride or oxalyl chloride.

Isatins of Formula 13 are obtained from aniline derivatives of Formula 12 using methods known in the literature. Oxidation of isatin 13 with hydrogen peroxide generally affords good yields of the corresponding isatoic anhydride 8 (Angew. Chem. Int. Ed. Engl. 1980, 19, 222-223). Isatoic anhydrides are also available from the anthranilic acids 11 via many known procedures involving reaction of 11 with phosgene or a phosgene equivalent.

The synthesis of compounds of Formula 4a in Scheme 11 involves as the key step introduction of the R⁷ substituent via alkylation or arylation of the pyrazole of Formula 14 with compounds of Formula 15 (wherein Lg is a leaving group as defined above). Oxidation of the methyl group affords the pyrazole carboxylic acid. Some of the more preferred R⁶ groups include haloalkyl.

These acids may be prepared via metallation and carboxylation of compounds of Formula 18 as the key step. The R⁷ group is introduced in a manner similar to that of Scheme 11, i.e. via alkylation or arylation with a compound of Formula 15. Representative R⁶ groups include e.g. cyano, haloalkyl and halogen.

Reaction of a pyrazole of Formula 17 with a 2,3-dihalopyridine of Formula 15a affords good yields of the 1-pyridylpyrazole of Formula 18a with good specificity for the desired regiochemistry. Metallation of 18a with lithium diisopropylamide (LDA) followed by quenching of the lithium salt with carbon dioxide affords the 1-(2-pyridinyl)pyrazole-carboxylic acid of Formula 4b. Additional details for these procedures are provided in Examples 1, 3, 6, 8 and 10.

Scheme 14 involves reaction of an optionally substituted phenyl hydrazine of Formula 19 with a ketopyruvate of Formula 20 to yield pyrazole esters of Formula 21. Hydrolysis of the esters affords the pyrazole acids of Formula 4c. This procedure is particularly useful for the preparation of compounds in which R⁷ is optionally substituted phenyl and R⁶ is haloalkyl.

The method of Scheme 15 involves 3+2 cycloaddition of an appropriately substituted iminohalide 22 with either substituted propiolates of Formula 23 or acrylates of Formula 25. Cycloaddition with an acrylate requires additional oxidation of the intermediate pyrazoline to the pyrazole. Hydrolysis of the esters affords the pyrazole acids of Formula 4c. Preferred iminohalides for this reaction include the trifuoromethyl iminochloride of Formula 26 and the iminodibromide of Formula 27. Compounds such as 26 are known (J. Heterocycl. Chem. 1985, 22(2), 565-8). Compounds such as 27 are available by known methods (Tetrahedron Letters 1999, 40, 2605). These procedures are particularly useful for the preparation of compounds where R⁷ is optionally substituted phenyl and R⁶ is haloalkyl or bromo.

In the method of Scheme 16, metallation of the sulfamoyl pyrazole of Formula 28 with n-butyllithium followed by direct halogenation of the anion with either hexachloroethane (for R⁶ being Cl) or 1,2-dibromotetrachloroethane (for R⁶ being Br) affords the halogenated derivatives of Formula 29. Removal of the sulfamoyl group with trifluoroacetic acid (TFA) at room temperature proceeds cleanly and in good yield to afford the pyrazoles of Formula 17c. One skilled in the art will recognize that Formula 17c is a tautomer of Formula 17b. Further experimental details for these procedures are described in Examples 8 and 10.

Reaction of a compound of Formula 30 wherein R¹³ is C₁-C₄ alkyl with a suitable base in a suitable organic solvent affords the cyclized product of Formula 31 after neutralization with an acid such as acetic acid. The suitable base can be, for example but not limitation, sodium hydride, potassium t-butoxide, dimsyl sodium (CH₃S(O)CH₂⁻Na⁺), alkali metal (such as lithium, sodium or potassium) carbonates or hydroxides, tetraalkyl (such as methyl, ethyl or butyl)ammonium fluorides or hydroxides, or 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphonine. The suitable organic solvent can be, for example but not limitation, acetone, acetonitrile, tetrahydrofuran, dichloromethane, dimethylsulfoxide, or N,N-dimethylformamide. The cyclization reaction is usually conducted in a temperature range from about 0 to 120° C. The effects of solvent, base, temperature and addition time are all interdependent, and choice of reaction conditions is important to minimize the formation of byproducts. A preferred base is tetrabutylammonium fluoride.

Dehydration of the compound of Formula 31 to give the compound of Formula 32, followed by converting the carboxylic ester function to carboxylic acid, affords the compound of Formula 4d. The dehydration is effected by treatment with a catalytic amount of a suitable acid. This catalytic acid can be, for example but not limitation, sulfuric acid. The reaction is generally conducted using an organic solvent. As one skilled in the art will realize, dehydration reactions may be conducted in a wide variety of solvents in a temperature range generally between about 0 and 200° C,, more preferably between about 0 and 100° C. For the dehydration in the method of Scheme 17, a solvent comprising acetic acid and temperatures of about 65° C. are preferred. Carboxylic ester compounds can be converted to carboxylic acid compounds by numerous methods including nucleophilic cleavage under anhydrous conditions or hydrolytic methods involving the use of either acids or bases (see T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 2nd ed., John Wiley & Sons, Inc., New York, 1991, pp. 224-269 for a review of methods). For the method of Scheme 17, base-catalyzed hydrolytic methods are preferred. Suitable bases include alkali metal (such as lithium, sodium or potassium) hydroxides. For example, the ester can be dissolved in a mixture of water and an alcohol such as ethanol. Upon treatment with sodium hydroxide or potassium hydroxide, the ester is saponified to provide the sodium or potassium salt of the carboxylic acid. Acidification with a strong acid, such as hydrochloric acid or sulfuric acid, yields the carboxylic acid of Formula 4d. The carboxylic acid can be isolated by methods known to those skilled in the art, including crystallization, extraction and distillation.

wherein R⁶ is H, C₁-C₆ alkyl or C₁-C₆ haloalkyl and R¹³ is C₁-C₄ alkyl

Treatment of a hydrazine compound of Formula 33 with a ketone of Formula 34 in a solvent such as water, methanol or acetic acid gives the hydrazone of Formula 35. One skilled in the art will recognize that this reaction may require catalysis by an optional acid and may also require elevated temperatures depending on the molecular substitution pattern of the hydrazone of Formula 35. Reaction of the hydrazone of Formula 35 with the compound of Formula 36 in a suitable organic solvent such as, for example but not limitation, dichloromethane or tetrahydrofuran in the presence of an acid scavenger such as triethylamine provides the compound of Formula 30. The reaction is usually conducted at a temperature between about 0 and 100° C. Further experimental details for the method of Scheme 18 are illustrated in Example 17. Hydrazine compounds of Formula 33 can be prepared by standard methods, such as by contacting the corresponding halo compound of Formula 15a with hydrazine.

wherein R¹³ is C₁-C₄ alkyl.

Oxidization of the compound of Formula 37 optionally in the presence of acid to give the compound of Formula 32 followed by conversion of the carboxylic ester function to the carboxylic acid provides the compound of Formula 4d. The oxidizing agent can be hydrogen peroxide, organic peroxides, potassium persulfate, sodium persulfate, ammonium persulfate, potassium monopersulfate (e.g., Oxone®) or potassium permanganate. To obtain complete conversion, at least one equivalent of oxidizing agent versus the compound of Formula 37 should be used, preferably between about one to two equivalents. This oxidation is typically carried out in the presence of a solvent. The solvent can be an ether, such as tetrahydrofuran, p-dioxane and the like, an organic ester, such as ethyl acetate, dimethyl carbonate and the like, or a polar aprotic organic such as N,N-dimethylformamide, acetonitrile and the like. Acids suitable for use in the oxidation step include inorganic acids, such as sulfuric acid, phosphoric acid and the like, and organic acids, such as acetic acid, benzoic acid and the like. The acid, when used, should be used in greater than 0.1 equivalents versus the compound of Formula 37. To obtain complete conversion, one to five equivalents of acid can be used. The preferred oxidant is potassium persulfate and the oxidation is preferably carried out in the presence of sulfuric acid. The reaction can be carried out by mixing the compound of Formula 37 in the desired solvent and, if used, the acid. The oxidant can then be added at a convenient rate. The reaction temperature is typically varied from as low as about 0° C. up to the boiling point of the solvent in order to obtain a reasonable reaction time to complete the reaction, preferably less than 8 hours. The desired product, a compound of Formula 32 can be isolated by methods known to those skilled in the art, including crystallization, extraction and distillation. Methods suitable for converting the ester of Formula 32 to the carboxylic acid of Formula 4d are already described for Scheme 17. Further experimental details for the method of Scheme 19 are illustrated in Examples 12 and 13.

wherein R¹³ is C₁-C₄ alkyl and R⁶ is halogen.

Treatment of a compound of Formula 38 with a halogenating reagent, usually in the presence of a solvent, affords the corresponding halo compound of Formula 37. Halogenating reagents that can be used include phosphorus oxyhalides, phosphorus trihalides, phosphorus pentahalides, thionyl chloride, dihalotrialkylphosphoranes, dihalodiphenylphosphoranes, oxalyl chloride and phosgene. Preferred are phosphorus oxyhalides and phosphorus pentahalides. To obtain complete conversion, at least 0.33 equivalents of phosphorus oxyhalide versus the compound of Formula 38 (i.e. the mole reatio of phosphorus oxyhalide to Formula 18 is at least 0.33) should be used, preferably between about 0.33 and 1.2 equivalents. To obtain complete conversion, at least 0.20 equivalents of phosphorus pentahalide versus the compound of Formula 38 should be used, preferably between about 0.20 and 1.0 equivalents. Compounds of Formula 38 wherein R¹³ is C₁-C₄ alkyl are preferred for this reaction. Typical solvents for this halogenation include halogenated alkanes, such as dichloromethane, chloroform, chlorobutane and the like, aromatic solvents, such as benzene, xylene, chlorobenzene and the like, ethers, such as tetrahydrofuran, p-dioxane, diethyl ether, and the like, and polar aprotic solvents such as acetonitrile, N,N-dimethylformamide, and the like. Optionally, an organic base, such as triethylamine, pyridine, N,N-dimethylaniline or the like, can be added. Addition of a catalyst, such as N,N-dimethylformamide, is also an option. Preferred is the process in which the solvent is acetonitrile and a base is absent. Typically, neither a base nor a catalyst is required when acetonitrile solvent is used. The preferred process is conducted by mixing the compound of Formula 38 in acetonitrile. The halogenating reagent is then added over a convenient time, and the mixture is then held at the desired temperature until the reaction is complete. The reaction temperature is typically between 20° C. and the boiling point of acetonitrile, and the reaction time is typically less than 2 hours. The reaction mass is then neutralized with an inorganic base, such as sodium bicarbonate, sodium hydroxide and the like, or an organic base, such as sodium acetate. The desired product, a compound of Formula 37, can be isolated by methods known to those skilled in the art, including crystallization, extraction and distillation.

Alternatively, compounds of Formula 37 wherein R⁶ is halogen can be prepared by treating the corresponding compounds of Formula 37 wherein R⁶ is a different halogen (e.g., Cl for making Formula 37 wherein R³ is Br) or a sulfonate group such as p-toluenesulfonate, benzenesulfonate and methanesulfonate with the appropriate hydrogen halide. By this method the R⁶ halogen or sulfonate substituent on the Formula 37 starting compound is replaced with, for example, Br or Cl from hydrogen bromide or hydrogen chloride, respectively. The reaction is conducted in a suitable solvent such as dibromomethane, dichloromethane or acetonitrile. The reaction can be conducted at or near atmospheric pressure or above atmospheric pressure in a pressure vessel. When R⁶ in the starting compound of Formula 37 is a halogen such as Cl, the reaction is preferably conducted in such a way that the hydrogen halide generated from the reaction is removed by sparging or other suitable means. The reaction can be conducted between about 0 and 100° C., most conveniently near ambient temperature (e.g., about 10 to 40° C.), and more preferably between about 20 and 30° C. Addition of a Lewis acid catalyst (such as aluminum tribromide for preparing Formula 37 wherein R⁶ is Br) can facilitate the reaction. The product of Formula 37 is isolated by the usual methods known to those skilled in the art, including extraction, distillation and crystallization. Further details for this process are illustrated in Example 14.

Starting compounds of Formula 37 wherein R⁶ is Cl or Br can be prepared from corresponding compounds of Formula 38 as already described. Starting compounds of Formula 37 wherein R⁶ is a sulfonate group can likewise be prepared from corresponding compounds of Formula 38 by standard methods such as treatment with a sulfonyl chloride (e.g., p-toluenesulfonyl chloride) and base such as a tertiary amine (e.g., triethylamine) in a suitable solvent such as dichloromethane; further details for this process are illustrated in Example 15.

wherein R¹³ is C₁-C₄ alkyl, and X is a leaving group.

In this method, instead of being halogenated as shown in Scheme 20, the compound of Formula 38 is oxidized to the compound of Formula 32a. The reaction conditions for this oxidation are as already described for the conversion of the compound of Formula 37 to the compound of Formula 32 in Scheme 19.

The compound of Formula 32a is then alkylated to form the compound of Formula 32b by contact with an alkylating agent CF₃CH₂X (39) in the presence of a base. In the alkylating agent 39, X is a nucleophilic reaction leaving group such as halogen (e.g., Br, I), OS(O)₂CH₃ (methanesulfonate), OS(O)₂CF₃, OS(O)₂Ph-p-CH₃ p-toluenesulfonate), and the like; methanesulfonate works well. The reaction is conducted in the presence of at least one equivalent of a base. Suitable bases include inorganic bases, such as alkali metal (such as lithium, sodium or potassium) carbonates and hydroxides, and organic bases, such as triethylamine, diisopropylethylamine and 1,8-diazabicyclo[5.4.0]undec-7-ene. The reaction is generally conducted in a solvent, which can comprise alcohols, such as methanol and ethanol, halogenated alkanes, such as dichloromethane, aromatic solvents, such as benzene, toluene and chlorobenzene, ethers, such as tetrahydrofuran, and polar aprotic solvents, such as acetonitrile, such as such as acetonitrile, N,N-dimethylformamide, and the like. Alcohols and polar aprotic solvents are preferred for use with inorganic bases. Potassium carbonate as base and acetonitrile as solvent are preferred. The reaction is generally conducted between about 0 and 150° C., with most typically between ambient temperature and 100° C. The product of Formula 32b can be isolated by conventional techniques such as extraction. The ester of Formula 32b can then be converted to the carboxylic acid of Formula 4d by the methods already described for the conversion of Formula 32 to Formula 4d in Scheme 17. Further experimental details for the method of Scheme 21 are illustrated in Example 16.

wherein R¹³ is C₁-C₄ alkyl.

In this method, a hydrazine compound of Formula 33 is contacted with a compound of Formula 40 (a fumarate ester or maleate ester or a mixture thereof may be used) in the presence of a base and a solvent. The base is typically a metal alkoxide salt, such as sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, potassium tert-butoxide, lithium tert-butoxide, and the like. Greater than 0.5 equivalents of base versus the compound of Formula 33 should be used, preferably between 0.9 and 1.3 equivalents. Greater than 1.0 equivalents of the compound of Formula 40 should be used, preferably between 1.0 to 1.3 equivalents. Polar protic and polar aprotic organic solvents can be used, such as alcohols, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide and the like. Preferred solvents are alcohols such as methanol and ethanol. It is especially preferred that the alcohol be the same as that making up the fumarate or maleate ester and the alkoxide base. The reaction is typically conducted by mixing the compound of Formula 33 and the base in the solvent. The mixture can be heated or cooled to a desired temperature and the compound of Formula 40 added over a period of time. Typically reaction temperatures are between 0° C. and the boiling point of the solvent used. The reaction may be conducted under greater than atmospheric pressure in order to increase the boiling point of the solvent. Temperatures between about 30 and 90° C. are generally preferred. The addition time can be as quick as heat transfer allows. Typical addition times are between 1 minute and 2 hours. Optimum reaction temperature and addition time vary depending upon the identities of the compounds of Formula 33 and Formula 40. After addition, the reaction mixture can be held for a time at the reaction temperature. Depending upon the reaction temperature, the required hold time may be from 0 to 2 hours. Typical hold times are 10 to 60 minutes. The reaction mass then can be acidified by adding an organic acid, such as acetic acid and the like, or an inorganic acid, such as hydrochloric acid, sulfuric acid and the like. Depending on the reaction conditions and the means of isolation, the —CO₂R¹³ function on the compound of Formula 38 may be hydrolyzed to —CO₂H; for example, the presence of water in the reaction mixture can promote such hydrolysis. If the carboxylic acid (—CO₂H) is formed, it can be converted back to —CO₂R¹³ wherein R¹³ is C₁-C₄ alkyl using esterification methods well-known in the art. The desired product, a compound of Formula 38, can be isolated by methods known to those skilled in the art, such as crystallization, extraction or distillation.

It is recognized that some reagents and reaction conditions described above for preparing compounds of Formula I may not be compatible with certain functionalities present in the intermediates. In these instances, the incorporation of protection/deprotection sequences or functional group interconversions into the synthesis will aid in obtaining the desired products. The use and choice of the protecting groups will be apparent to one skilled in chemical synthesis (see, for example, Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis, 2nd ed.; Wiley: New York, 1991). One skilled in the art will recognize that, in some cases, after the introduction of a given reagent as it is depicted in any individual scheme, it may be necessary to perform additional routine synthetic steps not described in detail to complete the synthesis of compounds of Formula I. One skilled in the art will also recognize that it may be necessary to perform a combination of the steps illustrated in the above schemes in an order other than that implied by the particular sequence presented to prepare the compounds of Formula I.

It is believed that one skilled in the art using the preceding description can prepare compounds of Formula I of the present invention to its fullest extent. The following Examples are, therefore, to be construed as merely illustrative, and not limiting of the disclosure in any way whatsoever. Percentages are by weight except for chromatographic solvent mixtures or where otherwise indicated. Parts and percentages for chromatographic solvent mixtures are by volume unless otherwise indicated. ¹H NMR spectra are reported in ppm downfield from tetramethylsilane; s means singlet, d means doublet, t means triplet, q means quartet, m means multiplet, dd means doublet of doublets, dt means doublet of triplets, br s means broad singlet.

A solution of 3-methyl-2-nitrobenzoic acid (2.00 g, 11.0 mmol) and triethylamine (1.22 g, 12.1 mmol) in 25 mL of methylene chloride was cooled to 10° C. Ethyl chloroformate was carefully added and a solid precipitate formed. After stirring for 30 minutes isopropylamine (0.94 g, 16.0 mmol) was added and a hom*ogeneous solution resulted. The reaction was stirred for an additional hour, poured into water and extracted with ethyl acetate. The organic extracts were washed with water, dried over magnesium sulfate and evaporated under reduced pressure to afford 1.96 g of the desired intermediate as a white solid melting at 126-128° C.

¹H NMR (CDCl₃) δ 1.24 (d, 6H), 2.38 (s, 3H), 4.22 (m, 1H), 5.80 (br s, 1H), 7.4 (m, 3H).

The 2-nitrobenzamide of Step A (1.70 g, 7.6 mmol) was hydrogenated over 5% Pd/C in 40 mL of ethanol at 50 psi. When the uptake of hydrogen ceased the reaction was filtered through Celite® diatomaceous filter aid and the Celite® was washed with ether. The filtrate was evaporated under reduced pressure to afford 1.41 g of the title compound as a solid melting at 149-151° C.

¹H NMR (CDCl₃) δ 1.24 (dd, 6H), 2.16 (s, 3H), 4.25 (m, 1H), 5.54 (br s, 2H), 5.85 (br s, 1H), 6.59 (t, 1H), 7.13 (d, 1H), 7.17 (d, 1H).

To a mixture of 3-trifluoromethylpyrazole (5 g, 37 mmol) and powdered potassium carbonate (10 g, 72 mmol) stirring in 30 mL of N,N-dimethylformamide, iodoethane (8 g, 51 mmol) was added dropwise. After a mild exotherm, the reaction was stirred overnight at room temperature. The reaction mixture was partitioned between 100 mL of diethyl ether and 100 mL of water. The ether layer was separated, washed with water (3×) and brine, and dried over magnesium sulfate. Evaporation of solvent in vacuo gave 4 g of oil.

To 3.8 g of this oil stirring in 40 mL of tetrahydrofuran under nitrogen in a dry ice/acetone bath, 17 mL of a 2.5 M solution of n-butyllithium in tetrahydrofuran (43 mmol) was added dropwise and the solution stirred for 20 minutes at −78° C. An excess of gaseous carbon dioxide was bubbled into the stirred solution at a moderate rate for 10 minutes. After addition of carbon dioxide, the reaction was allowed to slowly reach room temperature and stirred overnight. The reaction mixture was partitioned between diethyl ether (100 mL) and 0.5 N aqueous sodium hydroxide (100 mL). The basic layer was separated and acidified with concentrated hydrochloric acid to a pH of 2-3. The aqueous mixture was extracted with ethyl acetate (100 mL) and the organic extract washed with water and brine and dried over magnesium sulfate. The oily residue, which remained after evaporating the solvent in vacuo, was triturated to a solid from a small amount of 1-chlorobutane. After filtering and drying, a slightly impure sample of 1-ethyl-3-trifluoromethyl-pyrazol-5-yl carboxylic acid (1.4 g) was obtained as a broad-melting solid.

¹H NMR(CDCl₃) δ 1.51 (t, 3H), 4.68 (q, 2H), 7.23 (s, 1H), 9.85 (br s, 1H).

To a solution of 1-ethyl-3-trifluoromethyl-pyrazol-5-yl carboxylic acid (i.e. the product of Step C) (0.5 g, 2.4 mmol) stirring in 20 mL of methylene chloride, oxalyl chloride (1.2 mL, 14 mmol) was added. Upon addition of 2 drops of N,N-dimethylformamide, foaming and bubbling occurred. The reaction mixture was heated at reflux for 1 hr as a yellow solution. After cooling, the solvent was removed in vacuo and the resulting residue dissolved in 20 mL of tetrahydrofuran. To the stirred solution, 2-amino-3-methyl-N-(1-methylethyl)benzamide (i.e. the product of Step B) (0.7 g, 3.6 mmol) was added followed by the dropwise addition of N,N-diisopropylethylamine (3 mL, 17 mmol). After stirring at room temperature overnight, the reaction mixture was partitioned between ethyl acetate (100 mL) and 1N aqueous hydrochloric acid (75 mL). The separated organic layer was washed with water and brine and dried over magnesium sulfate. Evaporating in vacuo gave a white solid residue, which on purification by flash column chromatography on silica gel (2:1 hexanes/ethyl acetate) afforded 0.5 g of the tide compound, a compound of the present invention, melting at 223-226° C.

¹H NMR (DMSO-d₆) δ 1.06 (d, 6H), 1.36 (t, 3H), 2.45 (s, 3H), 3.97 (m, 1H), 4.58 (q, 2H), 7.43-7.25 (m, 3H), 7.45 (s, 1H), 8.05 (d, 1H), 10.15 (s, 1H).

A solution of 1,1,1-trifluoropentane-2,4-dione (20.0 g, 0.130 mole) in glacial acetic acid (60 mL) was cooled to 7° C. using an ice/water bath. Phenylhydrazine (14.1 g, 0.130 mole) was added dropwise over a period of 60 minutes. The reaction mass temperature increased to 15° C. during the addition. The resulting orange solution was held under ambient conditions for 60 minutes. The bulk of the acetic acid was removed by stripping on a rotary evaporator at a bath temperature of 65° C. The residue was dissolved in methylene chloride (150 mL). The solution was washed with aqueous sodium bicarbonate (3 g in 50 mL of water). The purple-red organic layer was separated, treated with activated charcoal (2 g) and MgSO₄, then filtered. Volatiles were removed on a rotary evaporator. The crude product consisted of 28.0 g of a rose-colored oil, which contained ˜89% the desired product and 11% 1-phenyl-5-(trifluoromethyl)-3-methylpyrazole.

¹H NMR (DMSO-d₆) δ 2.35 (s, 3H), 6.76 (s, 1H), 7.6-7.5 (m, 5H).

A sample of crude 2-methyl-1-phenyl-4-(trifluoromethyl)-1H-pyrazole (i.e. the product of Step A) (89%, 50.0 g, 0.221 mole) was mixed with water (400 mL) and cetyltrimethylammonium chloride (4.00 g, 0.011 mole). The mixture was heated to 95° C. Potassium permanganate was added in 10 equal portions, spaced at ˜8 minute intervals. The reaction mass was maintained at 95-100° C. during this period. After the last portion was added, the mixture was held for ˜15 minutes at 95-100° C., whereupon the purple, permanganate color had been discharged. The reaction mass was filtered while hot (˜75° C.) through a 1-cm bed of Celite® diatomaceous filter aid in a 150-mL coarse glass frit funnel. The filter cake was washed with warm (˜50° C.) water (3×100 mL). The combined filtrate and washings were extracted with ether (2×100 mL) to remove a small amount of yellow, water-insoluble material. The aqueous layer was purged with nitrogen to remove residual ether. The clear, colorless alkaline solution was acidified by adding concentrated hydrochloric acid dropwise until the pH reached ˜1.3 (28 g, 0.28 mole). Gas evolution was vigorous during the first two-thirds of the addition. The product was collected via filtration, washed with water (3×40 mL), then dried overnight at 55° C. in vacuo. The product consisted of 11.7 g of a white, crystalline powder, which was essentially pure based upon ¹ H NMR.

¹H NMR (CDCl₃) δ 7.33 (s, 1H), 7.4-7.5 (m, 5H).

A sample of crude 1-phenyl-3-(trifluoromethyl)pyrazole-5-carboxylic acid (i.e. the product of Step B) (4.13 g, 16.1 mmol) was dissolved in methylene chloride (45 mL). The solution was treated with oxalyl chloride (1.80 mL, 20.6 mmol), followed by N,N-dimethylformamide (0.010 mL, 0.13 mmol). Off-gassing began shortly after adding the N,N-dimethylformamide catalyst. The reaction mixture was stirred for ˜20 minutes under ambient conditions, then was heated to reflux for a period of 35 minutes. Volatiles were removed by stripping the reaction mixture on a rotary evaporator at a bath temperature of 55° C. The product consisted of 4.43 g of a light-yellow oil. The only impurity observed by ¹H NMR was N,N-dimethylformamide.

¹H NMR (CDCl₃) δ 7.40 (m, 1H), 7.42 (s, 1H), 7.50-7.53 (m, 4H).

A sample of 3-methylisatoic anhydride (0.30 g, 1.7 mmol) partially dissolved in pyridine (4.0 mL) was treated with 1-phenyl-3-(trifluoromethylpyrazole)-5-carboxyl chloride (i.e. the product of Step C) (0.55 g, 1.9 mmol). The mixture was heated to ˜95° C. for a period of 2 hours. The resulting orange solution was cooled to 29° C., then was treated with isopropylamine (1.00 g, 16.9 mmol). The reaction mass exothermically warmed to 39° C. It was further heated to 55° C. for a period of 30 minutes, whereupon much precipitate formed. The reaction mass was dissolved in dichloromethane (150 mL). The solution was washed with aqueous acid (5 mL of conc. HCl in 45 mL of water), then with aqueous base (2 g sodium carbonate in 50 mL of water). The organic layer was dried over MgSO₄, filtered, then concentrated on a rotary evaporator. Upon reduction to ˜4 mL, product crystals had formed. The slurry was diluted with ˜10 mL of ether, whereupon more product precipitated. The product was isolated by filtration, washed with ether (2×10 mL), then washed with water (2×50 mL). The wet cake was dried for 30 minutes at 70° C. in vacuo. The product, a compound of the present invention, consisted of 0.52 g of an off-white powder melting at 260-262° C.

¹H NMR (DMSO-d₆) δ 1.07 (d, 6H), 2.21 (s, 3H), 4.02 (octet, 1H), 7.2-7.4 (m, 3H), 7.45-7.6 (m, 6H), 8.10 (d, 1H), 10.31 (s, 1H).

A mixture of 2-chloro-3-trifluoromethylpyridine (3.62 g., 21 mmol), 3-trifluoro-methylpyrazole (2.7 g., 20 mmol), and potassium carbonate (6.0 g, 43 mmol) were heated at 100° C. for 18 h. The cooled reaction mixture was added to ice/water (100 mL). The mixture was extracted twice with ether (100 mL) and the combined ether extracts were washed twice with water (100 mL). The organic layer was dried with magnesium sulfate and concentrated to an oil. Chromatography on silica gel with hexanes:ethyl acetate 8:1 to 4:1 as eluent gave the title compound (3.5 g) as an oil.

¹H NMR (CDCl₃) δ 6.75 (m, 1H), 7.5 (m, 1H), 8.2 (m, 2H), 8.7 (m, 1H).

A mixture of the title compound of Example 3, Step A (3.4 g, 13 mmol) was dissolved in tetrahydrofuran (30 mL) and cooled to −70° C. Lithium diisopropylamide (2N in heptane/tetrahydrofuran, (Aldrich) 9.5 mL, 19 mmol) was added and the resulting dark mixture was stirred for 10 minutes. Dry carbon dioxide was bubbled through the mixture for 15 minutes. The mixture was allowed to warm to 23° C. and treated with water (50 mL) and 1N sodium hydroxide (10 mL). The aqueous mixture was extracted with ether (100 mL) and then ethyl acetate (100 mL). The aqueous layer was acidified with 6N hydrochloric acid to pH 1-2 and extracted twice with dichloromethane. The organic layer was dried with magnesium sulfate and concentrated to give the title compound (1.5 g).

¹H NMR (CDCl₃) δ 7.6 (m, 1H), 7.95 (m, 1H), 8.56 (m, 1H), 8.9 (m, 1H), 14.2 (br, 1H)

A mixture of the title compound of Example 3, Step B (0.54 g, 1.1 mmol), the title compound from Example 1, Step B (0.44 g, 2.4 mmol) and BOP chloride (bis(2-oxo-oxazolidinyl)phosphinyl chloride, 0.54 g, 2.1 mmol) in acetonitrile (13 mL) was treated with triethylamine (0.9 mL). The mixture was shaken in a closed scintillation vial for 18 h. The reaction was partitioned between ethyl acetate (100 mL) and 1N hydrochloric acid. The ethyl acetate layer was washed successively with 1N hydrochloric acid (50 mL), 1N sodium hydroxide (50 mL) and saturated sodium chloride solution (50 mL). The organic layer was dried over magnesium sulfate and concentrated. The residue was subjected to column chromatography on silica gel with hexanes/ethyl acetate (5:1 to 3:1) as eluent. The title compound (0.43 g), a compound of the present invention, was isolated as a white solid. m.p. 227-230° C.

¹H NMR (CDCl₃) δ 1.2 (m, 6H), 4.15 (m, 1H), 5.9 (br d, 1H), 7.1 (m, 1H), 7.2 (m, 2H), 7.4 (s, 1H), 7.6 (m, 1H), 8.15 (m, 1H), 8.74 (m, 1H), 10.4 (br, 1H).

To a mixture of 2,3-dichloropyridine (99.0 g, 0.67 mol) and 3-(trifluoromethyl)-pyrazole (83 g, 0.61 mol) in dry N,N-dimethylformamide (300 mL) was added potassium carbonate (166.0 g, 1.2 mol) and the reaction was then heated to 110-125° C. over 48 hours. The reaction was cooled to 100° C. and filtered through Celite® diatomaceous filter aid to remove solids. N,N-Dimethylformamide and excess dichloropyridine were removed by distillation at atmospheric pressure. Distillation of the product at reduced pressure (b.p. 139-141° C., 7 mm) afforded the desired intermediate as a clear yellow oil (113.4 g).

¹H NMR (CDCl₃) δ 6.78 (s, 1H), 7.36 (t, 1H), 7.93 (d, 1H), 8.15 (s, 1H), 8.45 (d, 1H).

To a solution of 3-chloro-2-[3-(trifluoromethyl)-1H-pyrazol-1-yl]pyridine (i.e. the product of Step A) (105.0 g, 425 mmol) in dry tetrahydrofuran (700 mL) at −75° C. was added via cannula a −30° C. solution of lithium diisopropylamide (425 mmol) in dry tetrahydrofuran (300 mL). The deep red solution was stirred for 15 minutes, after which time carbon dioxide was bubbled through at −63° C. until the solution became pale yellow and the exothermicity ceased. The reaction was stirred for an additional 20 minutes and then quenched with water (20 mL). The solvent was removed under reduced pressure, and the reaction mixture partitioned between ether and 0.5N aqueous sodium hydroxide solution. The aqueous extracts were washed with ether (3×), filtered through Celite® diatomaceous filter aid to remove residual solids, and then acidified to a pH of approximately 4, at which point an orange oil formed. The aqueous mixture was stirred vigorously and additional acid was added to lower the pH to 2.5-3. The orange oil congealed into a granular solid, which was filtered, washed successively with water and IN hydrochloric acid, and dried under vacuum at 50° C. to afford the title product as an off-white solid (130 g). (Product from another run following similar procedures melted at 175-176° C.)

¹H NMR (DMSO-d₆) δ 7.61 (s, 1H), 7.76 (dd, 1H), 8.31 (d, 1H), 8.60 (d, 1H).

To a solution of 2-amino-3-methylbenzoic acid (6 g) in dry 1,4-dioxane (50 mL) was added dropwise a solution of trichloromethyl chloroformate (8 mL) in dry 1,4-dioxane (25 mL), with ice-water cooling to keep the reaction temperature below 25° C. A white precipitate began to form during the addition. The reaction mixture was stirred at room temperature overnight. The precipitated solids were removed by filtration and washed with 1,4-dioxane (2×20 mL) and hexane (2×15 mL) and air-dried to yield 6.51 g of off-white solid.

¹H NMR (DMSO-d₆) δ 2.33 (s, 3H), 7.18 (t, 1H), 7.59 (d, 1H), 7.78 (d, 1H), 11.0 (br s, 1H).

To a suspension of the carboxylic acid product prepared as in Step B (146 g, 500 mmol) in dichloromethane (approximately 2 L) was added N,N-dimethylformamide (20 drops) and oxalyl chloride (67 mL, 750 mmol) in approximately 5-mL portions over approximately 2 h. Vigorous gas evolution occurred during the addition. The reaction mixture was stirred at room temperature overnight. The reaction mixture was concentrated in vacuo to provide the crude acid chloride as an opaque orange mixture. This material was taken up in dichloromethane, filtered to remove some solids and then reconcentrated and used without further purification. The crude acid chloride was dissolved in acetonitrile (250 mL) and added to a suspension of the product from Step C in acetonitrile (400 mL). Pyridine (250 mL) was added, the mixture was stirred for 15 min at room temperature, then warmed to reflux for 3 h. The resulting mixture was cooled to room temperature and stirred overnight to provide a solid mass. Additional acetonitrile was added and the mixture was mixed to form a thick slurry. The solids were collected and washed with cold acetonitrile. The solids were air-dried and the dried in vacuo at 90° C. for 5 h to yield 144.8 g of fluffy white solid.

¹H NMR (CDCl₃) δ 1.84 (s, 3H), 7.4 (t, 1H), 7.6 (m, 3H), 8.0 (dd, 1H), 8.1 (s, 1H), 8.6 (d, 1H).

To a suspension of the benzoxazinone product of Step D (124 g, 300 mmol) in dichloromethane (500 mL) was added dropwise isopropylamine (76 mL, 900 mmol) at room temperature. The temperature of the reaction mixture rose and the suspension thinned during the addition. The reaction mixture was then warmed to reflux for 1.5 h. A new suspension formed. The reaction mixture was cooled to room temperature and diethyl ether (1.3 L) was added and the mixture stirred at room temperature overnight. The solids were collected and washed with ether. The solids were air-dried and then dried in vacuo at 90° C. for 5 h to yield 122 g of the title compound, a compound of the present invention, as a fluffy white solid, melting at 194-196° C.

¹H NMR (CDCl₃) δ 1.23 (d, 6H), 2.21 (s, 3H), 4.2 (m, 1H), 5.9 (d, 1H), 7.2 (t, 1H), 7.3 (m, 2H), 7.31 (s, 1H), 7.4 (m, 1H), 7.8 (d, 1H), 8.5 (d, 1H), 10.4 (s, 1H).

To a solution of the carboxylic acid product prepared as in Example 4, Step B (28 g, 96 mmol) in dichloromethane (240 mL) was added N,N-dimethylformamide (12 drops) and oxalyl chloride (15.8 g, 124 mmol). The reaction mixture was stirred at room temperature until gas evolution ceased (approximately 1.5 h). The reaction mixture was concentrated in vacuo to provide the crude acid chloride as an oil that was used without further purification. The crude acid chloride was dissolved in acetonitrile (95 mL) and added to a solution of the benzoxazin-2,4-dione prepared as in Example 4, Step C in acetonitrile (95 mL). The resulting mixture was stirred at room temperature (approximately 30 min). Pyridine (95 mL) was added and the mixture heated to about 90° C. (approximately 1 h). The reaction mixture was cooled to about 35° C. and isopropylamine (25 mL) was added. The reaction mixture exothermically warmed during the addition and then was maintained at about 50° C. (approximately 1 h). The reaction mixture was then poured into ice water and stirred. The resulting precipitate was collected by filtration, washed with water and dried in vacuo overnight to provide 37.5 g of the title compound, a compound of the present invention, as a tan solid.

¹H NMR (CDCl₃) δ 1.23 (d, 6H), 2.21 (s, 3H), 4.2 (m, 1H), 5.9 (d, 1H), 7.2 (t, 1H), 7.3 (m, 2H), 7.31 (s, 1H), 7.4 (m, 1H), 7.8 (d, 1H), 8.5 (d, 1H), 10.4 (s, 1H).

To a solution of 2-amino-3-methylbenzoic acid (Aldrich, 15.0 g, 99.2 mmol) in N,N-dimethylformamide (50 mL) was added N-chlorosuccinimide (13.3 g, 99.2 mmol) and the reaction mixture was heated to 100° C. for 30 minutes. The heat was removed, the reaction was cooled to room temperature and let stand overnight. The reaction mixture was then slowly poured into ice-water (250 mL) to precipitate a white solid. The solid was filtered and washed four times with water and then taken up in ethyl acetate (900 mL). The ethyl acetate solution was dried over magnesium sulfate, evaporated under reduced pressure and the residual solid was washed with ether to afford the desired intermediate as a white solid (13.9 g).

¹H NMR (DMSO-d₆) δ 2.11 (s, 3H), 7.22 (s, 1H), 7.55 (s, 1H).

To a mixture of 2,3-dichloropyridine (99.0 g, 0.67 mol) and 3-trifluoromethyl pyrazole (83 g, 0.61 mol) in dry N,N-dimethylformamide (300 mL) was added potassium carbonate (166.0 g, 1.2 mol) and the reaction was then heated to 110-125° C. over 48 hours. The reaction was cooled to 100° C. and filtered through Celite® diatomaceous filter aid to remove solids. N,N-Dimethylformamide and excess dichloropyridine were removed by distillation at atomospheric pressure. Distillation of the product at reduced pressure (b.p. 139-141° C., 7 mm) afforded the title compound as a clear yellow oil (113.4 g).

¹NMR (CDCl₃) δ 6.78 (s, 1H), 7.36 (t, 1H), 7.93 (d, 1H), 8.15 (s, 1 H), 8.45 (d, 1H).

To a solution of the pyrazole product from Step B (105.0 g, 425 mmol) in dry tetrahydrofuran (700 mL) at −75° C. was added via cannula a -30° C. solution of lithium diisopropylamide (425 mmol) in dry tetrahydrofuran (300 mL). The deep red solution was stirred for 15 minutes, after which time carbon dioxide was bubbled through at −63° C. until the solution became pale yellow and the exothermicity ceased. The reaction was stirred for an additional 20 minutes and then quenched with water (20 mL). The solvent was removed under reduced pressure, and the reaction mixture was partitioned between ether and 0.5 N aqueous sodium hydroxide solution. The aqueous extracts were washed with ether (3×), filtered through Celite® diatomaceous filter aid to remove residual solids, and then acidified to a pH of approximately 4, at which point an orange oil formed. The aqueous mixture was stirred vigorously and additional acid was added to lower the pH to 2.5-3. The orange oil congealed into a granular solid, which was filtered, washed successively with water and 1N hydrochloric acid, and dried under vacuum at 50° C. to afford the title product as an off-white solid (130 g). (Product from another run following similar procedure melted at 175-176° C.)

¹H NMR (DMSO-d₆) δ 7.61 (s, 1H), 7.76 (dd, 1H), 8.31 (d, 1H), 8.60 (d, 1H).

To a solution of methanesulfonyl chloride (2.2 mL, 28.3 mmol) in acetonitrile (75 mL) was added dropwise a mixture of the carboxylic acid product from Step C (7.5 g, 27.0 mmol) and triethylamine (3.75 mL, 27.0 mmol) in acetonitrile (75 mL) at 0-5° C. The reaction temperature was then maintained at 0° C. throughout successive addition of reagents. After stirring for 20 minutes, 2-amino-3-methyl-5-chlorobenzoic acid from Step A (5.1 g, 27.0 mmol) was added and stirring was continued for an additional 5 minutes. A solution of triethylamine (7.5 mL, 54.0 mmol) in acetonitrile (15 mL) was then added dropwise, and the reaction mixture was stirred 45 minutes, followed by the addition of methanesulfonyl chloride (2.2 mL, 28.3 mmol). The reaction mixture was then warmed to room temperature and stirred overnight. Approximately 75 mL of water was then added to precipitate 5.8 g of a yellow solid. An additional 1 g of product was isolated by extraction from the filtrate to provide a total of 6.8 g of the title compound as a yellow solid.

¹H NMR (CDCl₃) δ 1.83 (s, 3H), 7.50 (s, 1H), 7.53 (m, 2H), 7.99 (m, 2H), 8.58 (d, 1H).

To a solution of the benzoxazinone product of Step D (5.0 g, 11.3 mmol) in tetrahydrofuran (35 mL) was added dropwise isopropylamine (2.9mL, 34.0mmol) in tetrahydrofuran (10 mL) at room temperature. The reaction mixture was then warmed until all solids had dissolved and stirred an additional five minutes, at which point thin layer chromatography on silica gel confirmed completion of the reaction. The tetrahydrofuran solvent was evaporated under reduced pressure, and the residual solid was purified by chromatography on silica gel, followed by trituration with ether/hexane to afford the title compound, a compound of the present invention, as a solid (4.6 g), melting at 195-196° C.

¹H NMR (CDCl₃) δ]1.21 (d, 6H), 2.17 (s, 3H), 4.16 (m, 1H), 5.95 (br, d 1H), 7.1-7.3 (m, 2H), 7.39 (s, 1H), 7.4 (m, 1H), 7.84 (d, 1H), 8.50 (d, 1H), 10.24 (br s, 1H).

To a solution of the benzoxazinone product of Example 6, Step D (4.50 g, 10.18 mmol) in tetrahydrofuran (THF; 70 mL) was added methylamine (2.0 M solution in THF, 15 mL, 30.0 mmol) dropwise and the reaction mixture was stirred at room temperature for 5 minutes. The tetrahydrofuran solvent was evaporated under reduced pressure and the residual solid was purified by chromatography on silica gel to afford 4.09 g of the title compound, a compound of the present invention, as a white solid melting at 185-186° C.

¹H NMR DMSO-d₆) δ 2.17 (s, 3H), 2.65 (d, 3H), 7.35 (d, 1H), 7.46 (dd, 1H), 7.65 (dd, 1H), 7.74 (s, 1H), 8.21 (d, 1H), 8.35 (br q, 1H), 8.74 (d, 1H), 10.39 (s, 1H).

To a solution of N-dimethylsulfamoylpyrazole (188.0 g, 1.07 mol) in dry tetrahydrofuran (1500 mL) at −78° C. was added dropwise a solution of 2.5 M n-butyllithium (472 mL, 1.18 mol) in hexane while maintaining the temperature below −65° C. Upon completion of the addition the reaction mixture was maintained at −78° C. for an additional 45 minutes, after which time a solution of hexachloroethane (279 g, 1.18 mol) in tetrahydrofuran (120 mL) was added dropwise. The reaction mixture was maintained for an hour at −78° C., warmed to −20° C. and then quenched with water (1 L). The reaction mixture was extracted with methylene chloride (4×500 mL); the organic extracts were dried over magnesium sulfate and concentrated. The crude product was further purified by chromatography on silica gel using methylene chloride as eluent to afford the title product compound as a yellow oil (160 g).

¹H NMR(CDCl₃) δ 3.07 (d, 6H), 6.33 (s, 1H), 7.61 (s, 1M).

To trifluoroacetic acid (290 mL) was added dropwise the chloropyrazole product (160 g) from Step A, and the reaction mixture was stirred at room temperature for 1.5 hours and then concentrated at reduced pressure. The residue was taken up in hexane, insoluble solids were filtered off, and the hexane was concentrated to afford the crude product as an oil. The crude product was further purified by chromatography on silica gel using ether/hexane (40:60) as eluent to afford the title product as a yellow oil (64.44 g).

¹H NMR (CDCl₃) δ 6.39 (s, 1H), 7.66 (s, 1H), 9.6 (br s, 1H).

To a mixture of 2,3-dichloropyridine (92.60 g, 0.629 mol) and 3-chloropyrazole (i.e. the product of Step B) (64.44 g, 0.629 mol) in N,N-dimethylformamide (400 mL) was added potassium carbonate (147.78 g, 1.06 mol), and the reaction mixture was then heated to 100° C. for 36 hours. The reaction mixture was cooled to room temperature and slowly poured into ice water. The precipitated solids were filtered and washed with water. The solid filter cake was taken up in ethyl acetate, dried over magnesium sulfate and concentrated. The crude solid was chromatographed on silica gel using 20% ethyl acetate/hexane as eluent to afford the title product as a white solid (39.75 g).

¹H NMR (CDCl₃) δ 6.43 (s, 1H), 7.26 (m, 1H), 7.90 (d, 1H), 8.09 (s, 1H), 8.41 (d, 1H).

To a solution of the pyrazole product from Step C (39.75 g, 186 mmol) in dry tetrahydrofuran (400 mL) at −78° C. was added dropwise a solution of 2.0 M lithium diisopropylamide (93 mL, 186 mmol) in tetrahydrofuran. Carbon dioxide was bubbled through the amber solution for 14 minutes, after which time the solution became pale brownish-yellow. The reaction was made basic with IN aqueous sodium hydroxide solution and -extracted with ether (2×500 mL). The aqueous extracts were acidified with 6 N hydrochloric acid and extracted with ethyl acetate (3×500 mL). The ethyl acetate extracts were dried over magnesium sulfate and concentrated to afford the title product as an off-white solid (42.96 g). (Product from another run following similar procedure melted at 198-199° C.)

¹H NMR (DMSO-d₆) δ 6.99 (s, 1H), 7.45 (m, 1H), 7.93 (d, 1H), 8.51 (d, 1H).

To a solution of methanesulfonyl chloride (6.96 g, 61.06 mmol) in acetonitrile (150 mL) was added dropwise a mixture of the carboxylic acid product from Step D (15.0 g, 58.16 mmol) and triethylamine (5.88 g, 58.16 mmol) in acetonitrile (150 mL) at −5° C. The reaction mixture was then stirred for 30 minutes at 0° C. Then, 2-amino-3-methyl-5-chlorobenzoic acid from Example 6, Step A (10.79 g, 58.16 mmol) was added, and stirring was continued for an additional 10 minutes. A solution of triethylamine (11.77 g, 116.5 mmol) in acetonitrile was then added dropwise while keeping the temperature below 10° C. The reaction mixture was stirred 60 minutes at 0° C., and then methanesulfonyl chloride (6.96 g, 61.06 mmol) was added. The reaction mixture was then warmed to room temperature and stirred for an additional 2 hours. The reaction mixture was then concentrated, and the crude product was chromatographed on silica gel using methylene chloride as eluent to afford the title product as a yellow solid (9.1 g).

¹H NMR (CDCl₃) δ 1.81 (s, 3H), 7.16 (s, 1H), 7.51 (m, 2H), 7.98 (d, 2H), 8.56 (d, 1H).

To a solution of the benzoxazinone product of Step E (6.21 g, 15.21 mmol) in tetahydrofuran (100 mL) was added isopropylamine (4.23 g, 72.74 mmol) and the reaction mixture was then heated to 60° C., stirred for 1 hour and then cooled to room temperature. The tetrahydrofuran solvent was evaporated under reduced pressure, and the residual solid was purified by chromatography on silica gel to afford the title compound, a compound of the present invention, as a white solid (5.05 g) melting at 173-175° C.

¹H NMR (CDCl₃) δ 1.23 (d, 6H), 2.18 (s, 3H), 4.21 (m, 1H), 5.97 (d, 1H), 7.01 (m, 1H), 7.20 (s, 1H), 7.24 (s, 1H), 7.41 (d, 1H), 7.83 (d, 1H), 8.43 (d, 1H), 10.15 (br s, 1H).

To a solution of the benzoxazinone product of Example 8, Step E (6.32 g, 15.47 mmol) in tetrahydrofuran (50 mL) was added methylamine (2.0 M solution in THF, 38 mL, 77.38 mmol), and the reaction mixture was heated to 60° C., stirred for 1 hour and then cooled to room temperature. The tetrahydrofuran solvent was evaporated under reduced pressure, and the residual solid was purified by chromatography on silica gel to afford the title compound, a compound of the present invention, as a white solid (4.57 g) melting at 225-226° C.

¹H NMR (CDCl₃) δ 2.15 (s, 3H), 2.93 (s, 3H), 6.21 (d, 1H), 7.06 (s, 1H), 7.18 (s, 1H), 7.20 (s, 1H), 7.42 (m, 1H), 7.83 (d, 1H), 8.42 (d, 1H), 10.08 (br s, 1H).

To a solution of N-dimethylsulfamoylpyrazole (44.0 g, 0.251 mol) in dry tetrahydrofuran (500 mL) at −78° C. was added dropwise a solution of n-butyllithium (2.5 M in hexane, 105.5 mL, 0.264 mol) while maintaining the temperature below −60° C. A thick solid formed during the addition. Upon completion of the addition the reaction mixture was maintained for an additional 15 minutes, after which time a solution of 1,2-dibromo-tetrachloroethane (90 g, 0.276 mol) in tetrahydrofuran (150 mL) was added dropwise while maintaining the temperature below −70° C. The reaction mixture turned a clear orange; stirring was continued for an additional 15 minutes. The −78° C. bath was removed and the reaction was quenched with water (600 mL). The reaction mixture was extracted with methylene chloride (4×), and the organic extracts were dried over magnesium sulfate and concentrated. The crude product was further purified by chromatography on silica gel using methylene chloride/hexane (50:50) as eluent to afford the title product as a clear colorless oil (57.04 g).

¹H NMR (CDCl₃) δ 3.07 (d, 6H), 6.44 (m, 1H), 7.62 (m, 1H).

To trifluoroacetic acid (70 mL) was slowly added the bromopyrazole product (57.04 g) from Step A. The reaction mixture was stirred at room temperature for 30 minutes and then concentrated at reduced pressure. The residue was taken up in hexane, insoluble solids were filtered off, and the hexane was evaporated to afford the crude product as an oil. The crude product was further purified by chromatography on silica gel using ethyl acetate/dichloromethane (10:90) as eluent to afford an oil. The oil was taken up in dichloromethane, neutralized with aqueous sodium bicarbonate solution, extracted with methylene chloride (3×), dried over magnesium sulfate and concentrated to afford the title product as a white solid (25.9 g), m.p. 61-64° C.

¹H NMR (CDCl₃) δ 6.37 (d, 1H), 7.59 (d, 1H), 12.4 (br s, 1H).

To a mixture of 2,3-dichloropyridine (27.4 g, 185 mmol) and 3-bromopyrazole (i.e. the product of Step B) (25.4 g, 176 mmol) in dry N,N-dimethylformamide (88 mL) was added potassium carbonate (48.6 g, 352 mmol), and the reaction mixture was heated to 125° C. for 18 hours. The reaction mixture was cooled to room temperature and poured into ice water (800 mL). A precipitate formed. The precipitated solids were stirred for 1.5 hrs, filtered and washed with water (2×100 mL). The solid filter cake was taken up in methylene chloride and washed sequentially with water, 1N hydrochloric acid, saturated aqueous sodium bicarbonate solution, and brine. The organic extracts were then dried over magnesium sulfate and concentrated to afford 39.9 g of a pink solid. The crude solid was suspended in hexane and stirred vigorously for 1 hr. The solids were filtered, washed with hexane and dried to afford the title product as an off-white powder (30.4 g) determined to be >94% pure by NMR. This material was used without further purification in Step D.

¹H NMR (CDCl₃) δ 6.52 (s, 1H), 7.30 (dd, 1H), 7.92 (d, 1H), 8.05 (s, 1H), 8.43 (d, 1H).

To a solution of the pyrazole product from Step C (30.4 g, 118 mmol) in dry tetrahydrofuran (250 mL) at −76° C. was added dropwise a solution of lithium diisopropylamide (118 mmol) in tetrahydrofuran at such a rate as to maintain the temperature below −71° C. The reaction mixture was stirred for 15 minutes at −76° C., and carbon dioxide was then bubbled through for 10 minutes, causing warming to −57° C. The reaction mixture was warmed to −20° C. and quenched with water. The reaction mixture was concentrated and then taken up in water (1 L) and ether (500 mL), and then aqueous sodium hydroxide solution (1 N, 20 mL) was added. The aqueous extracts were washed with ether and acidified with hydrochloric acid. The precipitated solids were filtered, washed with water and dried to afford the title product as a tan solid (27.7 g). (Product from another run following similar procedure melted at 200-201° C.)

¹H NMR(DMSO-d₆) δ 7.25 (s, 1H), 7.68 (dd, 1H), 8.24 (d, 1H), 8.56 (d, 1H).

A procedure analogous to that of Example 6, Step D was used to convert the pyrazolecarboxylic acid product from Example 10, Step D (1.5 g, 4.96 mmol) and 2-amino-3-methyl-5-chlorobenzoic acid (0.92 g, 4.96 mmol) to the title product as a solid (1.21 g).

¹H NMR (CDCl₃) δ 2.01 (s, 3H), 7.29 (s, 1H), 7.42 (d, 1H), 7.95 (d, 1H), 8.04 (m, 1H), 8.25 (s, 1H), 8.26 (d, 1H).

To a solution of the benzoxazinone product of Step E (0.20 g, 0.44 mmol) in tetrahydrofuran was added isopropylamine (0.122 mL, 1.42 mmol), and the reaction mixture was heated to 60° C. for 90 minutes and then cooled to room temperature. The tetrahydrofuran solvent was evaporated under reduced pressure, and the residual solid was triturated with ether, filtered, and dried to afford the title compound, a compound of the present invention, as a solid (150 mg), m.p. 159-161° C.

¹H NMR (CDCl₃) δ 1.22 (d, 6H), 2.19 (s, 3H), 4.21 (m, 1H), 5.99 (m, 1H), 7.05 (m, 1H), 7.22 (m, 2H), 7.39 (m, 1H), 7.82 (d, 1H), 8.41 (d, 1H).

To a solution of the benzoxazinone product of Example 10, Step E (0.20 g, 0.44 mmol) in tetrahydrofuran was added methylamine (2.0 M solution in THF, 0.514 mL, 1.02 mmol), and the reaction mixture was heated to 60° C. for 90 minutes and then cooled to room temperature. The tetrahydrofuran solvent was evaporated under reduced pressure, and the residual solid was triturated with ether, filtered, and dried to afford the title compound, a compound of the present invention, as a solid (40 mg), m.p. 162-164° C.

¹H NMR(CDCl₃) δ 2.18 (s, 3H), 2.95 (s, 3H), 6.21 (m, 1H), 7.10 (s, 1H), 7.24 (m, 2H), 7.39 (m, 1H), 7.80 (d, 1H), 8.45 (d, 1H).

The following Example 12 illustrates an alternative preparation of 3-chloro-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid, which can be used to prepare, for example, 3-chloro-N-[4-chloro-2-methyl-6-[[(1-methylethyl)amino]carbonyl]phenyl]-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxamide and 3-chloro-N-[4-chloro-2-methyl-6-[(methylamino)carbonyl]phenyl]-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxamide, by further steps illustrated in Examples 8 and 9.

A 2-L four-necked flask equipped with a mechanical stirrer, thermometer, addition funnel, reflux condenser, and nitrogen inlet was charged with absolute ethanol (250 mL) and an ethanolic solution of sodium ethoxide (21%, 190 mL, 0.504 mol). The mixture was heated to reflux at about 83° C. It was then treated with 3-chloro-2(1H)-pyridinone hydrazone (68.0 g, 0.474 mol). The mixture was re-heated to reflux over a period of 5 minutes. The yellow slurry was then treated dropwise with diethyl maleate (88.0 mL, 0.544 mol) over a period of 5 minutes. The reflux rate increased markedly during the addition. By the end of the addition all of the starting material had dissolved. The resulting orange-red solution was held at reflux for 10 minutes. After being cooled to 65° C., the reaction mixture was treated with glacial acetic acid (50.0 mL, 0.873 mol). A precipitate formed. The mixture was diluted with water (650 mL), causing the precipitate to dissolve. The orange solution was cooled in an ice bath. Product began to precipitate at 28° C. The slurry was held at about 2° C. for 2 hours. The product was isolated via filtration, washed with aqueous ethanol (40%, 3×50 mL), and then air-dried on the filter for about 1 hour. The title product compound was obtained as a highly crystalline, light orange powder (70.3 g, 55% yield). No significant impurities were observed by ¹H NMR.

¹H NMR (DMSO-d₆) δ 1.22 (t, 3H), 2.35 (d, 1H), 2.91 (dd, 1H), 4.20 (q, 2H), 4.84 (d, 1H), 7.20 (dd, 1H), 7.92 (d, 1H), 8.27 (d, 1H), 10.18 (s, 1H).

To a 2-L four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen inlet was charged acetonitrile (1000 mL), ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate (i.e. the product of Step A) (91.0 g, 0.337 mol) and phosphorus oxychloride (35.0 mL, 0.375 mol). Upon adding the phosphorus oxychloride, the mixture self-heated from 22 to 25° C. and a precipitate formed. The light-yellow slurry was heated to reflux at 83° C. over a period of 35 minutes, whereupon the precipitate dissolved. The resulting orange solution was held at reflux for 45 minutes, whereupon it had become black-green. The reflux condenser was replaced with a distillation head, and 650 mL of solvent was removed by distillation. A second 2-L four-necked flask equipped with a mechanical stirrer was charged with sodium bicarbonate (130 g, 1.55 mol) and water (400 mL). The concentrated reaction mixture was added to the sodium bicarbonate slurry over a period of 15 minutes. The resulting, two-phase mixture was stirred vigorously for 20 minutes, at which time gas evolution had ceased. The mixture was diluted with dichloromethane (250 mL) and then was stirred for 50 minutes. The mixture was treated with Celite® 545 diatomaceous earth filter aid (11 g) and then filtered to remove a black, tarry substance that inhibited phase separation. Since the filtrate was slow to separate into distinct phases, it was diluted with dichloromethane (200 mL) and water (200 mL) and treated with more Celite® 545 (15 g). The mixture was filtered, and the filtrate was transferred to a separatory funnel. The heavier, deep green organic layer was separated. A rag layer (50 mL) was refiltered and then added to the organic layer. The organic solution (800 mL) was treated with magnesium sulfate (30 g) and silica gel (12 g), and the slurry was stirred magnetically for 30 minutes. The slurry was filtered to remove the magnesium sulfate and silica gel, which had become deep blue-green. The filter cake was washed with dichloromethane (100 mL). The filtrate was concentrated on a rotary evaporator. The product consisted of dark amber oil (92.0 g, 93% yield). The only appreciable impurities observed by ¹H NMR were 1% starting material and 0.7% acetonitrile.

¹H NMR (D)MSO-d₆) δ 1.15 (t, 3H), 3.26 (dd, 1H), 3.58 (dd, 1H), 4.11 (q, 2H), 5.25 (dd, 1H), 7.00 (dd, 1H), 7.84 (d, 1H), 8.12 (d, 1H).

A 2-L four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen inlet was charged with ethyl 3-chloro-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate (i.e. the product of Step B) (95% pure, 99.5 g, 0.328 mol), acetonitrile (1000 mL) and sulfuric acid (98%, 35.0 mL, 0.661 mol). The mixture self-heated from 22 to 35° C. upon adding the sulfuric acid. After being stirred for several minutes, the mixture was treated with potassium persulfate (140 g, 0.518 mol). The slurry was heated to reflux at 84° C. for 4.5 hours. The resulting orange slurry while still warm (50-65° C.) was filtered to remove a fine, white precipitate. The filter cake was washed with acetonitrile (50 mL). The filtrate was concentrated to about 500 mL on a rotary evaporator. A second 2-L four-necked flask equipped with a mechanical stirrer was charged with water (1250 mL). The concentrated reaction mass was added to the water over a period of about 5 minutes. The product was isolated via filtration, washed with aqueous acetonitrile (25%, 3×125 nL), washed once with water (100 mL), and then dried overnight in vacuo at room temperature. The product consisted of a crystalline, orange powder (79.3 g, 82% yield). The only appreciable impurities observed by ¹H NMR were about 1.9% water and 0.6% acetonitrile.

1H NMR (DMSO-d₆) δ 1.09 (t, 3H), 4.16 (q, 2H), 7.31 (s, 1H), 7.71 (dd, 1H), 8.38 (d, 1H), 8.59 (d, 1H).

A 1-L four-necked flask equipped with a mechanical stirrer, thermometer, and nitrogen inlet was charged with ethyl 3-chloro-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylate (i.e. the product of Step C) (97.5% pure, 79.3 g, 0.270 mol), methanol (260 mL), water (140 mL) and sodium hydroxide pellets (13.0 g, 0.325 mol). Upon adding the sodium hydroxide the mixture self-heated from 22 to 35° C., and the starting material began to dissolve. After being stirred for 45 minutes under ambient conditions, all of the starting material had dissolved. The resulting deep orange-brown solution was concentrated to about 250 mL on a rotary evaporator. The concentrated reaction mixture was then diluted with water (400 mL). The aqueous solution was extracted with ether (200 mL). Then the aqueous layer was transferred to a 1-L Erlenmeyer flask equipped with a magnetic stirrer. The solution was treated dropwise with concentrated hydrochloric acid (36.0 g, 0.355 mol) over a period of about 10 minutes. The product was isolated via filtration, reslurried with water (2×200 mL), cover washed once with water (100 mL) and then air-dried on the filter for 1.5 hours. The product consisted of a crystalline, light brown powder (58.1 g, 83% yield). About 0.7% ether was the only appreciable impurity observed by ¹H NMR.

¹H NMR (DMSO-d₆) δ 7.20 (s, 1H), 7.68 (dd, 1H), 8.25 (d, 1H), 8.56 (d, 1H), 13.95 (br, s, 1H).

The following Example 13 illustrates an alternative preparation of 3-bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid, which can be used to prepare, for example, 3-bromo-N-[4-chloro-2-methyl-6-[[(1-methylethyl)amino]carbonyl]phenyl]-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxamide and 3-bromo-N-[4-chloro-2-methyl-6-[(methylamino)carbonyl]phenyl]-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxamide, by further steps illustrated in Examples 10 and 11.

A 1-L four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen inlet was charged with acetonitrile (400 mL), ethyl 2-(3-chloro-2-Pyridinyl)-5-oxo-3-pyrazolidinecarboxylate (i.e. the product of Example 12, Step A) (50.0 g, 0.185 mol) and phosphorus oxybromide (34.0 g, 0.119 mol). The orange slurry was heated to reflux at 83° C. over a period of 20 minutes. The resulting turbid, orange solution was held at reflux for 75 minutes, at which time a dense, tan, crystalline precipitate had formed. The reflux condenser was replaced with a distillation head, and a cloudy, colorless distillate (300 mL) was collected. A second 1-L four-necked flask equipped with a mechanical stirrer was charged with sodium bicarbonate (45 g, 0.54 mol) and water (200 mL). The concentrated reaction mixture was added to the sodium bicarbonate slurry over a period of 5 minutes. The resulting two-phase mixture was stirred vigorously for 5 minutes, at which time gas evolution had ceased. The mixture was diluted with dichloromethane (200 mL) and then was stirred for 75 minutes. The mixture was treated with 5 g of Celite® 545 diatomaceous filter aid and then filtered to remove a brown, tarry substance. The filtrate was transferred to a separatory funnel. The brown organic layer (400 mL) was separated and then was treated with magnesium sulfate (15 g) and Darco® G60 activated charcoal (2.0 g). The resulting slurry was stirred magnetically for 15 minutes and then filtered to remove the magnesium sulfate and charcoal. The green filtrate was treated with silica gel (3 g) and stirred for several minutes. The deep blue-green silica gel was removed by filtration, and the filtrate was concentrated on a rotary evaporator. The product consisted of a light amber oil (58.6 g, 95% yield), which crystallized upon standing. The only appreciable impurity observed by ¹H NMR was 0.3% acetonitrile.

¹H NMR (DMSO-d₆) δ 1.15 (t, 3H), 3.29 (dd, 1H), 3.60 (dd, 1H), 4.11 (q, 2H), 5.20 (dd, 1H), 6.99 (dd, 1H), 7.84 (d, 1H), 8.12 (d, 1H).

A 1-L four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen inlet was charged with acetonitrile (330 mL), ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate (i.e. the product of Example 12, Step A) (52.0 g, 0.193 mol), and phosphorus pentabromide (41.0 g, 0.0952 mol). The orange slurry was heated to reflux at 84° C. over a period of 20 minutes. The resulting brick-red mixture was held at reflux for 90 minutes, at which time a dense tan crystalline precipitate had formed. The reflux condenser was replaced with a distillation head, and a cloudy, colorless distillate (220 mL) was collected. A second 1-L four-necked flask equipped with a mechanical stirrer was charged with sodium bicarbonate (40 g, 0.48 mol) and water (200 mL). The concentrated reaction mixture was added to the sodium bicarbonate slurry over a period of 5 minutes. The resulting, two-phase mixture was stirred vigorously for 10 minutes, at which time gas evolution had ceased. The mixture was diluted with dichloromethane (200 mL) and then was stirred for 10 minutes. The mixture was treated with Celite® 545 diatomaceous filter aid (5 g) and then filtered to remove a purple, tarry substance. The filter cake was washed with dichloromethane (50 mL). The filtrate was transferred to a separatory funnel. The purple-red organic layer (400 mL) was separated and then was treated with magnesium sulfate (15 g) and Darco® G60 activated charcoal (2.2 g). The slurry was stirred magnetically for 40 minutes. The slurry was filtered to remove the magnesium sulfate and charcoal. The filtrate was concentrated on a rotary evaporator. The product consisted of a dark amber oil (61.2 g, 95% yield), which crystallized upon standing. The only appreciable impurity observed by ¹H NMR was 0.7% acetonitrile.

¹H NMR (DMSO-d₆) δ 1.15 (t, 3H), 3.29 (dd, 1H), 3.60 (dd, 1H), 4.11 (q, 2H), 5.20 (dd, 1H), 6.99 (dd, 1H), 7.84 (d, 1H), 8.12 (d, 1H).

A 1-L four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen inlet was charged with ethyl 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate (i.e. the product of Steps A1 and A2) (40.2 g, 0.121 mol), acetonitrile (300 mL) and sulfuric acid (98%, 13.0 mL, 0.245 mol). The mixture self-heated from 22 to 36° C. upon adding the sulfuric acid. After being stirred for several minutes, the mixture was treated with potassium persulfate (48.0 g, 0.178 mol). The slurry was heated to reflux at 84° C. for 2 hours. The resulting orange slurry while still warm (50-65° C.) was filtered to remove a white precipitate. The filter cake was washed with acetonitrile (2×50 mL). The filtrate was concentrated to about 200 mL on a rotary evaporator. A second 1-L four-necked flask equipped with a mechanical stirrer was charged with water (400 mL). The concentrated reaction mass was added to the water over a period of about 5 minutes. The product was isolated via filtration, washed sequentially with aqueous acetonitrile (20%, 100 mL) and water (75 mL), and was then air-dried on the filter for 1 hour. The product consisted of a crystalline, orange powder (36.6 g, 90% yield). The only appreciable impurities observed by 1H NMR were about 1% of an unknown and 0.5% acetonitrile.

¹H NMR (DMSO-d₆) δ 1.09 (t, 3H), 4.16 (q, 2H), 7.35 (s, 1H), 7.72 (dd, 1H), 8.39 (d, 1H), 8.59 (d, 1H).

A 300-mL four-necked flask equipped with a mechanical stirrer, thermometer, and nitrogen inlet was charged with ethyl 3-bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylate (i.e. the product of Step B) (98.5% pure, 25.0 g, 0.0756 mol), methanol (75 mL), water (50 mL), and sodium hydroxide pellets (3.30 g, 0.0825 mol). Upon adding the sodium hydroxide the mixture self-heated from 29 to 34° C. and the starting material began to dissolve. After being stirred for 90 minutes under ambient conditions, all of the starting material had dissolved. The resulting dark orange solution was concentrated to about 90 mL on a rotary evaporator. The concentrated reaction mixture was then diluted with water (160 mL). The aqueous solution was extracted with ether (100 mL). Then the aqueous layer was transferred to a 500-mL Erlenmeyer flask equipped with a magnetic stirrer. The solution was treated dropwise with concentrated hydrochloric acid (8.50 g, 0.0839 mol) over a period of about 10 minutes. The product was isolated via filtration, reslurried with water (2×40 mL), cover washed once with water (25 mL), and then air-dried on the filter for 2 hours. The product consisted of a crystalline, tan powder (20.9 g, 91% yield). The only appreciable impurities observed by ¹H NMR were about 0.8% of an unknown and 0.7% ether.

¹H NMR (DMSO-d₆) δ 7.25 (s, 1H), 13.95 (br s, 1H), 8.56 (d, 1H), 8.25 (d, 1H), 7.68 (dd, 1H).

The following Example 14 illustrates an alternative preparation of ethyl 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate, which can be used to prepare, for example, ethyl 3-bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylate (i.e. product of Example 13, Step B).

Hydrogen bromide was passed through a solution of ethyl 3-chloro-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate (i.e. product of Example 12, Step B) (8.45 g, 29.3 mmol) in dibromomethane (85 mL). After 90 minutes the gas flow was terminated, and the reaction mixture was washed with aqueous sodium bicarbonate solution (100 mL). The organic phase was dried and evaporated under reduced pressure to give the title product as an oil (9.7 g, 99% yield), which crystallized on standing.

¹H NMR (CDCl₃) δ 1.19 (t, 3H), 3.24 (½ of AB in ABX pattern, J=9.3, 17.3 Hz, 1H), 3.44(½ of AB in ABX pattern, J=11.7, 17.3 Hz, 1H), 4.18 (q, 2H), 5.25 (X of ABX, 1H, J=9.3, 11.9 Hz), 6.85 (dd, J=4.7, 7.7 Hz, 1H), 7.65 (dd, J=1.6, 7.8 Hz, 1H), 8.07 (dd, J=1.6, 4.8Hz, 1H).

The following Example 15 illustrates the preparation of ethyl 1-(3-chloro-2-pyridinyl)-4,5-dihydro-3-[[(4-methylphenyl)sulfonyl]oxy]-1H-pyrazole-5-carboxylate, which can be used to prepare ethyl 3-bromo-1-(3-chloro-2-pyridinyl)4,5-dihydro-1H-pyrazole-5-carboxylate by procedures similar to that described in Example 14.

Triethylamine (3.75 g, 37.1 mmol) was added dropwise to a mixture of ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate (i.e. the product of Example 12, Step A) (10.0 g, 37.1 mmol) and p-toluenesulfonyl chloride (7.07 g, 37.1 mmol) in dichloromethane (100 mL) at 0° C. Further portions of p-toluenesulfonyl chloride (0.35 g, 1.83 mmol) and triethylamine (0.19 g, 1.88 mmol) were added. The reaction mixture was then allowed to warm to room temperature and was stirred overnight. The mixture was then diluted with dichloromethane (200 mL) and washed with water (3×70 mL). The organic phase was dried and evaporated to leave the title product as an oil (13.7 g, 87% yield), which slowly formed crystals. Product recrystallized from ethyl acetate/hexanes melted at 99.5-100° C.

IR (nujol) ν 1740, 1638, 1576, 1446, 1343, 1296, 1228, 1191, 1178, 1084, 1027, 948, 969, 868, 845 cm⁻¹.

¹H NMR (CDCl₃) δ 1.19 (t, 3H), 2.45 (s, 3H), 3.12 (½ of AB in ABX pattern, J=17.3, 9 Hz, 1H), 3.33 (½ of AB in ABX pattern, J=17.5, 11.8 Hz, 1H), 4.16 (q, 2H), 5.72 (X of ABX, J=9, 11.8 Hz, 1H), 6.79 (dd, J=4.6, 7.7 Hz, 1H), 7.36 (d, J=8.4 Hz, 2H), 7.56 (dd, J=1.6, 7.8 Hz, 1H), 7.95 (d, J=8.4 Hz, 2H), 8.01 (dd, J=1.4, 4.6 Hz, 1H).

To a suspension of ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate (i.e. product of Example 12, Step A) (27 g, 100 mmol) stirred in dry acetonitrile (200 mL) was added sulfuric acid (20 g, 200 mmol) in one portion. The reaction mixture thinned to form a pale green, nearly clear solution before thickening again to form a pale yellow suspension. Potassium persulfate (33 g, 120 mmol) was added in one portion, and then the reaction mixture was heated at gentle reflux for 3.5 hours. After cooling using an ice bath, a precipitate of white solid was removed by filtration and discarded. The filtrate was diluted with water (400 mL) and then extracted three times with ethyl ether (700 mL total). Concentration of the combined ether extracts to a reduced volume (75 mL) caused precipitation of an off-white solid (3.75 g), which was collected by filtration. The ether mother liquor was further concentrated to yield a second crop of an off-white precipitate (4.2 g), which was also collected by filtration. An off-white solid also precipitated from the aqueous phase; this solid (4.5 g) was collected by filtration to provide a combined total of 12.45 g of the title compound.

¹H NMR (DMSO-d₆) δ 1.06 (t, 3H), 4.11 (q, 2H), 6.34 (s, 1H), 7.6 (t, 1H),8.19 (d, 1H), 8.5 (d, 1H), 10.6 (s, 1H).

To a suspension of ethyl 1-(3-chloro-2-pyridinyl)-2,3-dihydro-3-oxo-1H-pyrazole-5-carboxylate (i.e. product of Step A) (0.8 g, 3 mmol) stirred in dry acetonitrile (15 mL) at −5° C. was added potassium carbonate (0.85 g, 6.15 mmol). The suspension was stirred for 15 minutes at 20 ° C. The stirred suspension was then cooled to 5° C., and 2,2,2-trifluoro-ethyl trifluoromethanesulfonate (0.8 g, 3.45 mmol) was added dropwise. The reaction mixture was warmed to room temperature and then heated to reflux, at which time thin layer chromatography showed the reaction to be complete. Water (25 mL) was added to the reaction mixture, which was then extracted with ethyl ether. The ether extract was dried over magnesium sulfate and concentrated to yield the title product compound (1.05 g) as a pale yellow oil.

¹H NMR (CDCl₃) δ 1.21 (t, 3H), 4.20 (q, 2H), 4.63 (q, 2H), 6.53 (s, 1H), 7.4 (t, 1H), 7.9 (d, 1H), 8.5 (d, 1H).

To a stirred solution of ethyl 1-(3-chloro-2-pyridinyl)-3-(2,2,2-trifluoroethoxy)-1H-pyrazole-5-carboxylate (i.e. product of Step B) (0.92 g, 2.8 mmol) in methanol (15 mL) was added water (5 mL), which caused the reaction mixture to become cloudy. An aqueous solution of sodium hydroxide (50%, 1.5 g, 19.2 mmol) was added dropwise, and the reaction mixture was stirred at room temperature for 30 minutes, during which time the reaction mixture became again clear. Water (20 mL) was added and the reaction mixture was extracted with ethyl ether, which was discarded. The aqueous phase was acidified to pH 2 using concentrated hydrochloric acid and then extracted with ethyl acetate (50 mL). The ethyl acetate extract, which was washed with water (20 mL) and brine (20 mL), dried over magnesium sulfate and concentrated to give the title compound, isolated as a white solid (0.8 g).

¹H NMR (DMSO-d₆) δ 4.9 (q, 2H), 6.75 (s, 1H), 7.6 (t, 1H), 8.2 (d, 1H), 8.55 (d, 1H), 13.7 (bs, 1H).

To a suspension of 2-amino-3-methyl-5-chlorobenzoic acid (i.e. product of Example 6, Step A) (97 g, 520 mmol) stirred in dry dioxane (750 mL) at room temperature, trichloromethyl chloroformate (63 g, 320 mmol) was added dropwise. The reaction mixture exothermically warmed slowly to 42° C., and the solid almost completely dissolved before a thick suspension formed again. After the suspension was stirred at ambient temperature for 2.5 hours, the title compound was isolated by filtration, washed with ethyl ether, and dried to yield the title product compound, obtained as a white solid (98 g).

¹H NMR (DMSO-d₆) δ 2.3 (s, 3H), 7.70 (s, 1H), 7.75 (s, 11H), 11.2 (s, 1H).

To a suspension of 1-(3-chloro-2-pyridinyl)-3-(2,2,2-trifluoroethoxy)-1H-pyrazole-5-carboxylic acid (i.e. product of Step C) (7.9 g, 24mmol) stirred in dichloromethane (100 mL) was added N,N-dimethylformamide (4 drops). Oxalyl chloride (4.45 g, 35 mmol) was added dropwise over a period of 45 minutes. The resulting solution was stirred at room temperature for 4 hours and then concentrated under vacuum. The isolated acid chloride was dissolved in dry acetonitrile (10 mL) and added to a suspension of 6-chloro-8-methyl-2H-3,1-benzoxazine-2,4(1H)-dione (i.e. product of Step D) (4.9 g, 23 mmol) stirred in dry acetonitrile (14 mL). Pyridine (10 mL) was added, and the solution heated at reflux 6 hours. After cooling using an ice bath, a precipitate of white solid (9.15 g) was collected. The ¹H NMR spectrum of the collected precipitate showed peaks consistent with the title compound and residual 6-chloro-8-methyl-2H-3,1-benzoxazine-2,4(1H)-dione starting material. A small portion of the collected precipitate was recrystallized from acetonitrile to yield the pure title product melting at 178-180° C.

¹H NMR (DMSO-d₆) δ 1.72 (s, 3H), 4.96 (q, 2H), 7.04 (s, 1H), 7.7 (t, 1H), 7.75 (s, 1H), 7.9 (s, 1H), 8.3 (d, 1H), 8.6 (d, 1H).

To a suspension of the 6-chloro-2-[1-(3-chloro-2-pyridinyl)-3-(2,2,2-trifluoroethoxy)-1H-pyrazol-5-yl]-8-methyl4H-3,1-benzoxazin-4-one (i.e. precipitate product of Step E) (3.53 g, 7.5 mmol) in tetrahydrofuran (15 mL), methylamine (2.0 M solution in TBF, 11 mL, 22 mmol) was added dropwise, and the resulting solution was stirred at room temperature for 45 minutes. Thin layer chromatography then showed the reaction to be complete. Ethyl ether (100 mL) was added, and the reaction mixture was stirred for 2 hours while a precipitate formed. The precipitate was collected by filtration and then recrystallized from acetonitrile to yield a white solid (0.82 g). A second crop of white solid (0.35 g) precipitated from the acetonitrile mother liquor and was collected by filtration. The initial ether/tetrahydrofuran mother liquor was concentrated to dryness, and the residual solid was recrystallized from acetonitrile to yield a third crop of white solid (0.95 g). The three crops were combined, totaling 2.12 g (after drying) of the title compound, a compound of the present invention, isolated as a white solid, melting at 195-197° C.

¹H NMR (CDCl₃) δ 2.18 (s, 3H), 2.92 (d, 3H), 4.66 (q, 2H), 6.15 (q, 1H), 6.6 (s, 1H), 7.2 (s, 1H), 7.25 (s, 1H), 7.35 (t, 1H), 7.8 (d, 1H), 8.45 (d, 1H), 10.0 (s, 1H).

The following Example 17 illustrates an alternative preparation of 1-(3-chloro-2-pyridinyl)-3-(trifluoromethyl)-1H-pyrazole-5-carboxylic acid, which can be used to prepare, for example, 1-(3-chloro-2-pyridinyl)-N-[2-methyl-6-[[(1-methylethyl)amino]carbonyl]-phenyl]-3-(trifluoromethyl)-1H-pyrazole-5-carboxamide, by further steps illustrated in Examples 4.

1,1,1-Trifluoroacetone (7.80 g, 69.6 mmol) was added to 3-chloro-2(1H)-pyridinone hydrazone (alternatively named (3-chloro-pyridin-2-yl)-hydrazine) (10 g, 69.7 mmol) at 20-25° C. After the addition was complete, the mixture was stirred for about 10 minutes. The solvent was removed under reduced pressure and the mixture partitioned between ethyl acetate (100 mL) and saturated aqueous sodium carbonate solution (100 mL). The organic layer was dried and evaporated Chromatography on silica gel (eluted with ethyl acetate) gave the product as an off-white solid (11 g, 66% yield), m.p. 64-64.5° C. (after crystallization from ethyl acetate/hexanes).

IR (nujol) ν 1629, 1590, 1518, 1403, 1365, 1309, 1240, 1196, 1158, 1100, 1032, 992, 800 cm⁻¹. ¹H NMR (CDCl₃) δ 2.12 (s, 3H), 6.91−6.86 (m, 1H), 7.64−7.61 (m, 1H), 8.33−8.32 (m, 2H). MS nm/z 237 (M⁺).

Triethylamine (20.81 g, 0.206 mol) was added to 3-chloro-2(1H)-pyridinone (2,2,2-trifluoro-1-methylethylidene)hydrazone (i.e. the product of Step A) (32.63 g, 0.137 mol) in dichloromethane (68 mL) at 0° C. Ethyl chlorooxoacetate (18.75 g, 0.137 mol) in dichloromethane (69 mL) was added dropwise to the mixture at 0° C. The mixture was allowed to warm to 25° C. over about 2 hours. The mixture was cooled to 0° C. and a further portion of ethyl chlorooxoacetate (3.75 g, 27.47 mmol) in dichloromethane (14 mL) was added dropwise. After about an additional 1 hour, the mixture was diluted with dichloromethane (about 450 mL), and the mixture was washed with water (2×150 mL). The organic layer was dried and evaporated. Chromatography on silica gel (eluted with 1:1 ethyl acetate-hexanes) gave the product as a solid (42.06 g, 90% yield), m.p. 73.0-73.5° C. (after crystallization from ethyl acetate/hexanes).

IR (nujol) ν 1751, 1720, 1664, 1572, 1417, 1361, 1330, 1202, 1214, 1184, 1137, 1110, 1004, 1043, 1013, 942, 807, 836 cm⁻¹. ¹H NMR (DMSO-d₆, 115° C.) 1.19 (t, 3H), 1.72 (br s, 3H), 4.25 (q, 2H), 7.65 (dd, J=8.3, 4.7 Hz, 1H), 8.20 (dd, J=7.6, 1.5 Hz, 1H), 8.55 (d, J=3.6 Hz, 1H). MS m/z 337 (M⁺).

Ethyl hydrogen ethanedioate (3-chloro-2-pyridinyl)(2,2,2-trifluoro-1-methyl-ethylidene)hydrazide (i.e. the product of Step B) (5 g, 14.8 mmol) in dimethyl sulfoxide (25mL) was added to tetrabutylammonium fluoride hydrate (10 g) in dimethyl sulfoxide (25 mL) over 8 hours. When the addition was complete, the mixture was poured into acetic acid (3.25 g) in water (25 mL). After stirring at 25° C. overnight, the mixture was then extracted with toluene (4×25 mL), and the combined toluene extracts were washed with water (50 mL), dried and evaporated to give a solid. Chromatography on silica gel (eluted with 1:2 ethyl acetate-hexanes) gave the product as a solid (2.91 g, 50% yield, containing about 5% of 3-chloro-2(1H)-pyridinone (2,2,2-trifluoro-1-methylethylidene)hydrazone), m.p. 78-78.5° C. (after recrystallization from ethyl acetate/hexanes).

IR (nujol) ν 3403, 1726, 1618, 1582, 1407, 1320, 1293, 1260, 1217, 1187, 1150, 1122, 1100, 1067, 1013, 873, 829 cm⁻¹. ¹H NMR (CDCl₃) δ 1.19 (s, 3H), 3.20 (½ of ABZ pattern, J=18 Hz, 1H), 3.42 (½ of ABZ pattern, J=18 Hz, 1H), 4.24 (q, 2H), 6.94 (dd, J=7.9,4.9 Hz, 1H), 7.74 (dd, J=7.7, 1.5 Hz, 1H), 8.03 (dd, J=4.7, 1.5 Hz, 1H). MS m/z 319(M⁺).

Sulfuric acid (concentrated, 2 drops) was added to ethyl 1-(3-chloro-2-pyridinyl)-4,5-dihydro-5-hydroxy-3-(trifluoromethyl)-1H-pyrazole-5-carboxylate (i.e. the product of Step C) (1 g, 2.96 mmol) in acetic acid (10 mL) and the mixture was warmed to 65° C. for about 1 hour. The mixture was allowed to cool to 25° C. and most of the acetic acid was removed under reduced pressure. The mixture was partitioned between saturated aqueous sodium carbonate solution (100 mL) and ethyl acetate (100 mL). The aqueous layer was further extracted with ethyl acetate (100 mL). The combined organic extracts were dried and evaporated to give the product as an oil (0.66 g, 77% yield).

IR (neat) ν 3147, 2986, 1734, 1577, 1547, 1466, 1420, 1367, 1277, 1236, 1135, 1082, 1031, 973, 842, 802 cm⁻¹. ¹H NMR (CDCl₃) δ 1.23 (t, 3H), 4.25 (q, 2H), 7.21 (s, 1H), 7.48 (dd, J=8.1, 4.7 Hz, 1H), 7.94 (dd, J=6.6, 2 Hz, 1H), 8.53 (dd, J=4.7, 1.5 Hz, 1H). MS m/z 319 (M⁺).

Potassium hydroxide (0.5 g, 85%, 2.28 mmol) in water (1 mL) was added to ethyl 1-(3-chloro-2-pyridinyl)-3-(trifluoromethyl)-1H-pyrazole-5-carboxylate (i.e. the product of Step D) (0.66 g, 2.07 mmol) in ethanol (3 mL). After about 30 minutes, the solvent was removed under reduced pressure, and the mixture was dissolved in water (40 mL). The solution was washed with ethyl acetate (20 mL). The aqueous layer was acidified with concentrated hydrochloric acid and was extracted with ethyl acetate (3×20 mL). The combined extracts were dried and evaporated to give the product as a solid (0.53 g, 93% yield), m.p. 178-179° C. (after crystallization from hexanes-ethyl acetate).

IR (nujol) ν 1711, 1586, 1565, 1550, 1440, 1425, 1292, 1247, 1219, 1170, 1135, 1087, 1059, 1031, 972, 843, 816 cm⁻¹. ¹H NMR (DMSO-d₆) δ 7.61 (s, 1H), 7.77 (m, 1H), 8.30 (d, 1H), 8.60 (s, 1H).

Examples 18 and 19 illustrate alternatives to reaction conditions described in Example 10, Step E and Example 8, Step E, respectively.

Methanesulfonyl chloride (1.0 mL, 1.5 g, 13 mmol) was dissolved in acetonitrile (10 mL), and the mixture was cooled to −5° C. A solution of 3-bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid (i.e. the pyrazolecarboxylic acid product of Example 10, Step D) (3.02 g, 10 mmol) and pyridine (1.4 mL, 1.4 g, 17 mmol) in acetonitrile (10 mL) was added dropwise over 5 minutes at −5 to 0° C. A slurry formed during the addition. The mixture was stirred 5 minutes at this temperature, and then a mixture of 2-amino-3-methyl-5-chlorobenzoic acid (i.e. the product of Example 6 Step A) (1.86 g, 10 mmol) and pyridine (2.8 mL, 2.7 g, 35 mmol) in acetonitrile (10 mL) was added, rinsing with more acetonitrile (5 mL). The mixture was stirred 15 minutes at −5 to 0° C., and then methanesulfonyl chloride (1.0 mL, 1.5 mL, 13 mmol) in acetonitrile (5 mL) was added dropwise over 5 minutes at a temperature of −5 to 0° C. The reaction mixture was stirred 15 minutes more at this temperature, then allowed to warm slowly to room temperature, and stirred 4 h. Water (20 mL) was added dropwise, and the mixture was stirred 15 minutes. Then the mixture was filtered, and the solids were washed with 2:1 acetonitrile-water (3×3 mL), then with acetonitrile (2×3 mL), and dried under nitrogen to afford the title product as a light yellow powder, 4.07 g (90.2% crude yield), melting at 203-205° C. HPLC of the product using a Zorbax® RX-C8 chromatography column (4.6 mm×25 cm, eluent 25-95% acetonitrile/ pH 3 water) showed a major peak corresponding to the title compound and having 95.7% of total chromatogram peak area.

¹H NMR (DMSO-d₆) δ 1.72 (s, 3H) 7.52 (s, 1H), 7.72-7.78 (m, 2H), 7.88 (m, 1H), 8.37 (dd, 1H), 8.62 (dd, 1H).

Methanesulfonyl chloride (1.0 mL, 1.5 g, 13 mmol) was dissolved in acetonitrile (10 mL), and the mixture was cooled to −5° C. A solution of 3-chloro-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid (i.e. the carboxylic acid product of Example 8, Step D) (2.58 g, 10 mmol) and pyridine (1.4 mL, 1.4 g, 17 mmol) in acetonitrile (10 mL) was added dropwise over 5 minutes at −5 to 0° C. A slurry formed during the addition. The mixture was stirred 5 minutes at this temperature, and then 2-amino-3-methyl-5-chlorobenzoic acid (i.e. the product from Example 6, Step A) (1.86 g, 10 mmol) was added all at once. Then a solution of pyridine (2.8 mL, 2.7 g, 35 mmol) in acetonitrile (10 mL) was added dropwise in 5 min at −5 to 0° C. The mixture was stirred 15 minutes at −5 to 0° C., and then methanesulfonyl chloride (1.0 mL, 1.5 mL, 13 mmol) in acetonitrile (5 mL) was added dropwise in 5 min at −5 to 0° C. The reaction mixture was stirred 15 minutes at this temperature, then allowed to warm slowly to room temperature, and stirred 4 h. Water (15 mL) was added dropwise, and the mixture was stirred 15 minutes. Then the mixture was filtered, and the solids were washed with 2:1 acetonitrile-water (3×3 mL), then with acetonitrile (2×3 mL), and dried under nitrogen to afford the title product as a pale yellow powder, 3.83 g (94.0% crude yield), melting at 199-201° C. HPLC of the product using a Zorbax® RX-C8 chromatography column (4.6 mm×25 cm, eluent 25-95% acetonitrile/pH 3 water) showed a major peak corresponding to the title compound and having 97.8% of total chromatogram peak area.

¹H NMR (DMSO-d₆) δ 1.72 (s, 3H), 7.48 (s, 1H), 7.74-7.80 (m, 2H), 7.87 (m, 1H), 8.37 (dd, 1H), 8.62 (dd, 1H).