Isoxazol-benzamide compounds as antiparasitic compounds

Abstract

Compounds of formula (I), and pharmaceutically acceptable salts thereof, useful as treatments for parasitic diseases are provided. Also provided are pharmaceutical compositions comprising the compounds or pharmaceutically acceptable salts and methods of using the compounds, pharmaceutically acceptable salts, and pharmaceutical compositions in the treatment of various disorders, including parasitic disease or infection.

Description

ISOXAZOL-BENZAMIDE COMPOUNDS AND USES THEREOF CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.63 / 663,983, filed June 25, 2024; the entire contents of this application are hereby incorporated by reference herein. BACKGROUND

[0002] A number of parasites are known to infest mammals and cause irritation, disease, and health conditions. Parasites and pests such as fleas, ticks, mites, and lice can infest animals such as dogs and cats and cause health issues for the animals and those who come in contact with them. In many applications, long lasting effect against pests is desirable. Long lasting protection is particularly important with companion animals, such as dogs and cats and also mice, guinea pigs, ferrets, and rabbits; and with ranched animals such as cattle, sheep, pigs, and fish, in particular salmon and sea bass.

[0003] Aryl isoxazolines are used in agriculture, forestry, turf, household, wood products, nursery crops protection, and veterinary fields. Within the veterinary field, aryl isoxazolines are used in treatments of companion animals and livestock, including fish. For example, such inhibitors are disclosed in WO 2005 / 085216, WO 2007 / 079162, US 2007 / 066617, US20130131017, WO 2009 / 002809, WO 2009 / 112275, WO 2010 / 003923, WO 2010 / 070068, WO 2012 / 120399, WO 2013 / 079407, and WO 2021 / 127188.

[0004] Notwithstanding the availability of anti-parasitic agents available, there remains a need to improve the efficacy of bioavailable parasitic treatments in a manner that is long-lasting and safe for animal use. SUMMARY

[0005] In some embodiments, the disclosure relates to a compound of formula (I):or a pharmaceutically acceptable salt thereof, wherein: each of R1, R2, R3, and R4are independently selected from the group consisting of H, halo, CN, and CF3;each of X1and X2is independently F or CH3; and provided each of

[0006] In some aspects, at least two of R1, R2, R3, and R4are not –H. In some aspects, at least two of R1, R2, R3, and R4are halo. In some aspects, at least two of R1, R2, R3, and R4are Cl. In some aspects, at least two of R1, R2, R3, and R4are F or Cl.

[0007] In some aspects, at least one of R1, R2, R3, and R4is CF3.

[0008] In some aspects, R1and R4are selected from the group consisting of F or H.

[0009] In some aspects, R2and R3are selected from the group consisting of Cl, CN, or CF3.

[0010] In some aspects, at least one of X1and X2are CH3. In some aspects, X1and X2are CH3.

[0011] In some embodiments, the disclosure relates to a compound selected from Table A, or a pharmaceutically acceptable salt thereof.

[0012] In some aspects, the disclosure relates to an (S)-enantiomer of a compound.

[0013] In some aspects, the disclosure relates to a compound in a non-salt form.

[0014] In some embodiments, the disclosure relates to a pharmaceutical composition comprising a therapeutically effective amount of the compounds of the disclosure, or a pharmaceutically acceptable salt thereof, and one or more pharmaceutically acceptable carriers or vehicles.

[0015] In some embodiments, the disclosure relates to a method of treating a parasitic disease in a subject comprising administering to the subject a compound of the disclosure, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of the disclosure.

[0016] In some embodiments, the disclosure relates to a method of treating or lessening the severity in a subject of a parasitic infection comprising administering to the subject an effective amount of a compound of the disclosure, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of the disclosure.

[0017] In some aspects, the subject is a non-human animal.

[0018] In some embodiments, the disclosure relates to use of a compound the disclosure, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of the disclosure, as a medicament.

[0019] In some embodiments, the disclosure relates to use of a compound of the disclosure, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of the disclosure in the manufacture of a medicament for the treatment of a parasitic disease.

[0020] In one aspect, the disclosure relates to a compound described herein, or a pharmaceutically acceptable salt thereof.

[0021] In another aspect, the disclosure relates to a pharmaceutical composition comprising the compound, or a pharmaceutically acceptable salt thereof, and one or more pharmaceutically acceptable carriers or vehicles.

[0022] In still another aspect, the disclosure relates to a method of treating a parasitic infection or disease in a subject by administering the compound, pharmaceutically acceptable salt, or pharmaceutical composition to the subject.

[0023] In yet another aspect, the disclosure relates to a method of treating a flea or tick infestation in a subject by administering the compound, pharmaceutically acceptable salt, or pharmaceutical composition to the subject. DETAILED DESCRIPTION

[0024] In one aspect, the disclosure relates to a compound of formula (I):or a pharmaceutically acceptable salt thereof, wherein: each of R1, R2, R3, and R4are independently selected from the group consisting of H, halo, CN, and CF3; and provided each ofare excluded. For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75thEd. Additionally, general principles of organic chemistry are described in “Organic Chemistry,” Thomas Sorrell, University Science Books, Sausalito: 1999, and “March’s Advanced Organic Chemistry,” 5thEd.,Ed.: Smith, M.B. and March, J., John Wiley & Sons, New York: 2001, the entire contents of which are hereby incorporated by reference.

[0025] As described herein, the compounds of the disclosure comprise multiple variable groups (e.g., halo, -H, etc.). As one of ordinary skill in the art will recognize, combinations of groups envisioned by this disclosure are those combinations that result in the formation of stable or chemically feasible compounds. The term “stable,” in this context, refers to compounds that are not substantially altered when subjected to conditions to allow for their production, detection, and preferably their recovery, purification, and use for one or more of the purposes disclosed herein. In some embodiments, a stable compound or chemically feasible compound is one that is not substantially altered when kept at a temperature of 40°C or less, in the absence of moisture or other chemically reactive conditions, for at least a week.

[0026] As used herein, the term “halo” means F, Cl, Br or I.

[0027] Unless otherwise specified, the compounds of the disclosure, whether identified by chemical name or chemical structure, include all stereoisomers (e.g., enantiomers and diastereomers), double bond isomers (e.g., (Z) and (E)), conformational isomers, and tautomers of the compounds identified by the chemical names and chemical structures provided herein. In addition, single stereoisomers, double bond isomers, conformational isomers, and tautomers as well as mixtures of stereoisomers, double bond isomers, conformational isomers, and tautomers are within the scope of the disclosure.

[0028] As used herein, the term “compound,” when referring to the compounds of the disclosure, refers to a collection of molecules having identical chemical structures, except that there may be isotopic variation among the constituent atoms of the molecules. The term “compound” includes such a collection of molecules without regard to the purity of a given sample containing the collection of molecules. Thus, the term “compound” includes such a collection of molecules in pure form, in a mixture (e.g., solution, suspension, colloid, or pharmaceutical composition, or dosage form) with one or more other substances, or in the form of a hydrate, solvate, or co-crystal.

[0029] Animals in the context of the invention are understood to include vertebrates. The term vertebrate in this context is understood to comprise, for example fishes, amphibians, reptiles, birds, and mammals including humans. One preferred group of vertebrates according to the invention comprises warm-blooded animals including farm animals, such as cattle, horses, pigs, sheep and goats, poultry such as chickens, turkeys, guinea fowls and geese, fur-bearing animals such as mink, foxes, chinchillas, rabbits and the like, as well as companion animals such as ferrets, guinea pigs, rats, hamster, cats and dogs, and also humans. A further group of preferred vertebrates according to the invention comprises fishes including salmons.

[0030] As used herein, “infestation” or “disease” refers to the presence of parasites that pose a risk of nuisance or harm to humans or animals. The presence can be in the environment (e.g., in animal bedding), on the skin or fur of an animal, in an orifice of the animal, etc. When the infestation is within an animal (e.g., in the blood or other internal tissues), the term infestation or disease is intended to be synonymous with the term, “infection,” as that term is generally understood in the art.

[0031] The compounds of the disclosure are valuable active ingredients for use in pest control. The term “pests” includes ectoparasites and endoparasites on and in animals and in the hygiene field. Particular pests are fleas, ticks, mites, flies, worms, and lice. Even more particular pests are fleas and ticks

[0032] In the context of the present invention, ectoparasites are understood to be in particular insects, acari (mites and ticks), and crustaceans (sea lice). These include insects of the following orders: Lepidoptera, Coleoptera, Homoptera, Hemiptera, Heteroptera, Diptera, Dictyoptera, Thysanoptera, Orthoptera, Anoplura, Siphonaptera, Mallophaga, Thysanura, Isoptera, Psocoptera and Hymenoptera. However, the ectoparasites which may be mentioned in particular are those which trouble humans or animals and carry pathogens, for example flies such as Musca domestica, Musca vetustissima, Musca autumnalis, Fannia canicularis, Sarcophaga carnaria, Lucilia cuprina, Lucilia sericata, Hypoderma bovis, Hypoderma lineatum, Chrysomyia chloropyga, Dermatobia hominis, Cochliomyia hominivorax, Gasterophilus intestinalis, Oestrus ovis, biting flies such as Haematobia irritans irritans, Haematobia irritans exigua, Stomoxys calcitrans, horseflies (Tabanids) with the subfamilies of Tabanidae such as Haematopota spp. (e.g. Haematopotapluvialis) and Tabanus spp, (e.g.Tabanus nigrovittatus) and Chrysopsinae such as Chrysops spp. (e.g. Chrysops caecutiens); Hippoboscids such as Melophagus ovinus (sheep ked); tsetse flies, such as Glossinia spp,; other biting insects like midges, such as Ceratopogonidae (biting midges), Simuliidae (Blackflies), Psychodidae (Sandflies); but also blood- sucking insects, for example mosquitoes, such as Anopheles spp, Aedes spp and Culex spp, fleas, such as Ctenocephalides felis and Ctenocephalides canis (cat and dog fleas), Xenopsylla cheopis, Pulex irritans, Ceratophyllus gallinae, Dermatophiluspenetrans, blood-sucking lice (Anoplurd) such as Linognathus spp, Haematopinus spp, Solenopotes spp, Pediculus humanism but also chewing lice (Mallophaga) such as Bovicola (Damalinia) ovis, Bovicola (Damalinia) bovis and other Bovicola spp.. Ectoparasites also include members of the order Acarina, such as mites (e.g. Chorioptes bovis, Cheyletiella spp., Dermanyssus gallinae, Ortnithonyssus spp., Demodex canis, Sarcoptes scabiei, Psoroptes ovis and Psorergates spp. and ticks. Representatives ticks are, for example, Boophilus, Amblyomma, Anocentor, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, Rhipicentor, Margaropus, Rhipicephalus, Argas, Otobius and Ornithodoros and the like, which preferably infest vertebrates, for example warm-blooded animals including farm animals, such as cattle, horses, pigs, sheep and goats, poultry such as chickens, turkeys, guinea fowls, and geese, fur-bearing animals such as mink, foxes, chinchillas, rabbits and thelike, as well as companion animals such as ferrets, guinea pigs, rats, hamster, cats and dogs, but also humans and fishes.

[0033] The compounds of the disclosure according to the invention are also active against all or individual development stages of animal pests showing normal sensitivity, as well as those showing resistance to widely used parasiticides. This is especially true for resistant insects and members of the order Acarina. The insecticidal, ovicidal and / or acaricidal effect of the active substances of the invention can manifest itself directly, i.e. killing the pests either immediately or after some time has elapsed, for example when moulting occurs, or by destroying their eggs, or indirectly, e.g. reducing the number of eggs laid and / or the hatching rate, good efficacy corresponding to a pesticidal rate (mortality) of at least 50 to 60%.

[0034] Compounds of the disclosure can also be used against hygiene pests, especially of the order Diptera of the families Muscidae, Sarcophagidae, Anophilidae and Culicidae; the orders Orthoptera, Dictyoptera (e.g. the family Blattidae (cockroaches), such as Blatella germanica, Blatta orientalis, Periplaneta americana) and Hymenoptera (e.g. the families Formicidae (ants) and Vespidae (wasps).

[0035] The compounds of formula (I) are also effective against ectoparasites of fishes, especially the sub-class of Copepoda (e.g. order of Siphonostomatoida (sea lice), whilst being well tolerated by fish.

[0036] The compounds of formula (I) can also be used against worms of the class Cestoda, including the subclasses Eucestoda and Cestodaria.

[0037] Compounds of the disclosure also have sustainable efficacy on parasitic mites and insects of plants. In the case of spider mites of the order Acarina, they are effective against eggs, nymphs and adults of Tetranychidae (Tetranychus spp. and Panonychus spp). They have high activity against sucking insects of the order Homoptera, especially against pests of the families Aphididae, Delphacidae, Cicadellidae, Psyllidae, Loccidae, Diaspididae and Eriophydidae (e.g. rust mite on citrus fruits); the orders Hemiptera, Heteroptera and Thysanoptera, and on the plant-eating insects of the orders Lepidoptera, Coleoptera, Diptera and Orthoptera. They are similarly suitable as a soil insecticide against pests in the soil.

[0038] The compounds of formula (I) are therefore effective against all stages of development of sucking insects and eating insects on crops such as cereals, cotton, rice, maize, soya, potatoes, vegetables, fruit, tobacco, hops, citrus, avocados and other crops.

[0039] The compounds of formula I are also effective against plant nematodes of the species Meloidogyne, Heterodera, Pratylenchus, Ditylenchus, Radopholus, Rizoglyphus etc.

[0040] The compounds of the disclosure are effective against helminths. Helminths are commercially important because they cause serious diseases in mammals and poultry, e.g. in sheep, pigs, goats, cattle, horses, donkeys, camels, dogs, cats, rabbits, guinea-pigs, hamsters, chicken, turkeys, guinea fowls and other farmed birds, as well as exotic birds. Typical nematodes are: Haemonchus,Trichostrongylus, Ostertagia, Nematodirus, Cooperia, Ascaris, Bunostonum, Oesophagostonum, Charbertia, Trichuris, Strongylus, Trichonema, Dictyocaulus, Capillaria, Heterakis, Toxocara, Ascaridia, Oxyuris, Ancylostoma, Uncinaria, Toxascaris and Parascaris. The trematodes include, in particular, the family of Fasciolideae, especially Fasciola hepatica.

[0041] The pesticidal activity of the compounds of formula (I) according to the disclosure corresponds to a mortality rate of about 50-60% of the pests mentioned, more preferably to a mortality rate over 90%, most preferably to 95-100%. Compounds of the Disclosure

[0042] In one aspect, the disclosure relates to a compound of formula (I):or a pharmaceutically acceptable salt thereof, wherein: each of R1, R2, R3, and R4are independently selected from the group consisting of H, halo, CN, and CF3; aare excluded.

[0043] In some embodiments, each ofare excluded.

[0044] In some embodiments, each ofare excluded.

[0045] In another aspect, the disclosure relates to a compound of formula (IA):or a pharmaceutically acceptable salt thereof, wherein: each of R1, R2, R3, and R4are independently selected from the group consisting of H, halo, CN, and CF3; and provided each ofare excluded.

[0046] In another aspect, the disclosure relates to a compound of formula (IB):or a pharmaceutically acceptable salt thereof, wherein: each of R1, R2, R3, and R4are independently selected from the group consisting of H, halo, CN, and CF3; and provided each ofare excluded.

[0047] In some embodiments, the disclosure relates to a compound of formula (I), wherein at least three of R1, R2, R3, and R4are not H. In some embodiments, the disclosure relates to a compound of formula (I), wherein at least two of R1, R2, R3, and R4are not H. In some embodiments, the disclosure relates to a compound of formula (I), wherein two of R1, R2, R3, and R4are H. In some embodiments, thedisclosure relates to a compound of formula (I), wherein at least two of R1, R2, R3, and R4are halo. In some embodiments, the disclosure relates to a compound of formula (I), wherein at least two of R1, R2, R3, and R4are Cl. In some embodiments, the disclosure relates to a compound of formula (I), wherein at least two of R1, R2, R3, and R4are F or Cl.

[0048] In some embodiments, the disclosure relates to a compound of formula (I), wherein one of R1, R2, R3, and R4are F. In some embodiments, the disclosure relates to a compound of formula (I), wherein one of R1, R2, R3, and R4are Cl. In some embodiments, the disclosure relates to a compound of formula (I), wherein one of R1, R2, R3, and R4is CF3.

[0049] In some embodiments, the disclosure relates to a compound of formula (I), wherein one of R1and R4are F. In some embodiments, the disclosure relates to a compound of formula (I), wherein R1and R4are selected from the group consisting of F or H. In some embodiments, the disclosure relates to a compound of formula (I), wherein R1is selected from the group consisting of H or F. In some embodiments, the disclosure relates to a compound of formula (I), wherein R4is selected from the group consisting of H or F. In some embodiments, the disclosure relates to a compound of formula (I), wherein R1is F and R4is H. In some embodiments, the disclosure relates to a compound of formula (I), wherein R1is H and R4is F. In some embodiments, the disclosure relates to a compound of formula (I), wherein R1is F. In some embodiments, the disclosure relates to a compound of formula (I), wherein R1is H. In some embodiments, the disclosure relates to a compound of formula (I), wherein R4is F. In some embodiments, the disclosure relates to a compound of formula (I), wherein R4is H.

[0050] In some embodiments, the disclosure relates to a compound of formula (I), wherein R2and R3are not H. In some embodiments, the disclosure relates to a compound of formula (I), wherein R2and R3are selected from the group consisting of Cl, CN, or CF3. In some embodiments, the disclosure relates to a compound of formula (I), wherein R2is selected from the group consisting of Cl or CF3. In some embodiments, the disclosure relates to a compound of formula (I), wherein R3is selected from the group consisting of Cl, CN, or CF3. In some embodiments, the disclosure relates to a compound of formula (I), wherein one of R2and R3are Cl. In some embodiments, the disclosure relates to a compound of formula (I), wherein one of R2and R3are CF3. In some embodiments, the disclosure relates to a compound of formula (I), wherein R2is Cl and R3is CF3. In some embodiments, the disclosure relates to a compound of formula (I), wherein R2is CF3and R3is Cl. In some embodiments, the disclosure relates to a compound of formula (I), wherein R2is CF3and R3is CN. In some embodiments, the disclosure relates to a compound of formula (I), wherein R2and R3are Cl. In some embodiments, the disclosure relates to a compound of formula (I), wherein R2is Cl. In some embodiments, the disclosure relates to a compound of formula (I), wherein R2is CF3. In some embodiments, the disclosure relates to a compound of formula (I),wherein R3is Cl. In some embodiments, the disclosure relates to a compound of formula (I), wherein R3is CF3. In some embodiments, the disclosure relates to a compound of formula (I), wherein R3is CN.

[0051] In some embodiments, the disclosure relates to a compound of formula (I), wherein at least one of X1and X2are CH3. In some embodiments, the disclosure relates to a compound of formula (I), wherein at least one of X1and X2are F. In some embodiments, the disclosure relates to a compound of formula (I), wherein X1is F and X2is CH3. In some embodiments, the disclosure relates to a compound of formula (I), wherein X1is CH3and X2is F. In some embodiments, the disclosure relates to a compound of formula (I), wherein X1and X2are CH3. In some embodiments, the disclosure relates to a compound of formula (I), wherein X1and X2are F.

[0052] In some embodiments, the disclosure relates to a compound of formula (I), wherein the compound is an (S)-enantiomer.

[0053] In some embodiments, the disclosure relates to a compound of formula (I), wherein the compound is an (R)-enantiomer.

[0054] In some embodiments, the disclosure relates to a compound selected from Table A, or a pharmaceutically acceptable salt thereof. In other embodiments, the disclosure relates to a compound selected from Table A, i.e., the compound in non-salt form.

[0055] Table A. Compound Structures and Names.

[0056] In other embodiments, the disclosure relates to the foregoing compound in non-salt form. Such compound is considered to be a “compound of the disclosure,” as that term is used herein.Salts, Compositions, Uses, Formulation, Administration and Additional Agents Pharmaceutically acceptable salts and compositions

[0057] As discussed herein, the disclosure provides compounds, and pharmaceutically acceptable salts thereof, that are treatments of parasitic diseases and infections and thus the present compounds, and pharmaceutically acceptable salts thereof, are useful for the treatment of diseases, disorders, and conditions including, but not limited to parasitic diseases, flea infestations, tick infestations, mange, or ear mites. Accordingly, in another aspect of the disclosure, pharmaceutical compositions are provided, wherein these compositions comprise a compound as described herein, or a pharmaceutically acceptable salt thereof, and optionally comprise a pharmaceutically acceptable carrier, adjuvant or vehicle

[0058] As used herein, the term “pharmaceutically acceptable salt” refers to those salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit / risk ratio. A “pharmaceutically acceptable salt” of a compound of this disclosure includes any non-toxic salt that, upon administration to a recipient, is capable of providing, either directly or indirectly, a compound of this disclosure or an inhibitorily active metabolite or residue thereof. The salt may be in pure form, in a mixture (e.g., solution, suspension, or colloid) with one or more other substances, or in the form of a hydrate, solvate, or co-crystal.

[0059] Pharmaceutically acceptable salts are well known in the art. For example, S. M. Berge, et al. describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 1977, 66, 1-19, incorporated herein by reference. Pharmaceutically acceptable salts of the compound of this disclosure include those derived from suitable inorganic and organic acids and bases. Examples of pharmaceutically acceptable, nontoxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like. Salts derived from appropriate bases include alkali metal, alkaline earth metal,ammonium and N+(C1-4alkyl)4salts. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, lower alkyl sulfonate and aryl sulfonate.

[0060] As described herein, the pharmaceutically acceptable compositions of the disclosure additionally comprise a pharmaceutically acceptable carrier, adjuvant, or vehicle, which, as used herein, includes any and all solvents, diluents, or other liquid vehicle, dispersion or suspension aids, surface active agents, isotonic agents, thickening or emulsifying agents, preservatives, solid binders, lubricants, and the like, as suited to the particular dosage form desired. Remington’s Pharmaceutical Sciences, Sixteenth Edition, E. W. Martin (Mack Publishing Co., Easton, Pa., 1980) discloses various carriers used in formulating pharmaceutically acceptable compositions and known techniques for the preparation thereof. Except insofar as any conventional carrier medium is incompatible with the compounds of the disclosure, such as by producing any undesirable biological effect or otherwise interacting in a deleterious manner with any other component(s) of the pharmaceutically acceptable composition, its use is contemplated to be within the scope of this disclosure. Some examples of materials which can serve as pharmaceutically acceptable carriers include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, or potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, polyacrylates, waxes, polyethylene-polyoxypropylene-block polymers, wool fat, sugars such as lactose, glucose and sucrose; starches such as corn starch and potato starch; cellulose and its derivatives such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients such as cocoa butter and suppository waxes; oils such as peanut oil, cottonseed oil; safflower oil; sesame oil; olive oil; corn oil and soybean oil; glycols; such a propylene glycol or polyethylene glycol; esters such as ethyl oleate and ethyl laurate; agar; buffering agents such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer’s solution; ethyl alcohol, and phosphate buffer solutions, as well as other non-toxic compatible lubricants such as sodium lauryl sulfate and magnesium stearate, as well as coloring agents, releasing agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants can also be present in the composition, according to the judgment of the formulator.

[0061] In another aspect, the disclosure features a pharmaceutical composition comprising a compound of the disclosure, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

[0062] In another aspect, the disclosure features a pharmaceutical composition comprising a therapeutically effective amount of a compound, or a pharmaceutically acceptable salt thereof, and one or more pharmaceutically acceptable carriers or vehicles. Uses of Compounds and Pharmaceutically Acceptable Salts and Compositions

[0063] In another aspect, the disclosure features a method of treating a parasitic disease comprising administering to the subject a compound of the disclosure or a pharmaceutically acceptable salt thereof or a pharmaceutical composition thereof.

[0064] In yet another aspect, the disclosure features a method of treating or lessening the severity of a parasitic infection in the subject comprising administering an effective amount of a compound of the disclosure, a pharmaceutically acceptable salt thereof or a pharmaceutical composition thereof.

[0065] In some embodiments, the subject is a non-human animal. In certain embodiments, the subject is a dog. In certain embodiments, the subject is a cat. In some embodiments, the parasitic disease or infection is ticks. In some embodiments, the parasitic disease or infection is fleas. In some embodiments, the parasitic disease or infection is a worm. Compounds, Pharmaceutically Acceptable Salts, and Compositions for Use

[0066] In another aspect, the disclosure features a compound of the disclosure, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, for use as a medicament.

[0067] In another aspect, the disclosure features a compound of the disclosure, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, for use in the treatment of a parasitic disease.

[0068] In another aspect, the disclosure features a compound of the disclosure, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, for use in a method of treating a parasitic disease or infection.

[0069] In some embodiments, the parasitic disease or infection is treated in a non-human animal. In certain embodiments, the parasitic disease or infection is treated in a dog. In certain embodiments, the parasitic disease or infection is treated in a cat. In some embodiments, the parasitic disease or infection is ticks. In some embodiments, the parasitic disease or infection is fleas. In some embodiments, the parasitic disease or infection is a worm.Manufacture of Medicaments

[0070] In another aspect, the disclosure provides the use of a compound of the disclosure, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, for the manufacture of a medicament.

[0071] In another aspect, the disclosure provides the use of a compound of the disclosure, a pharmaceutically acceptable salt thereof, or a pharmaceutical composition thereof for the manufacture of a medicament for use in the treatment of a parasitic infection or disease.

[0072] In yet another aspect, the disclosure provides the use of a compound of the disclosure, a pharmaceutically acceptable salt thereof, or a pharmaceutical composition thereof for the manufacture of a medicament for use in treating a parasitic infection or disease. Administration of Compounds, Pharmaceutically Acceptable Salts, and Compositions

[0073] In certain embodiments of the disclosure, an “effective amount” of a compound of the disclosure, a pharmaceutically acceptable salt thereof, or a pharmaceutical composition thereof is that amount effective for treating or lessening the severity of one or more of the conditions recited above.

[0074] The compounds, salts, and compositions, according to the method of the disclosure, may be administered using any amount and any route of administration effective for treating or lessening the severity of one or more of the parasitic infections or diseases recited herein. The exact amount required will vary from subject to subject, depending on the species, age, and general condition of the subject, the severity of the condition, the particular agent, its mode of administration, and the like. The compounds, salts, and compositions of the disclosure are preferably formulated in dosage unit form for ease of administration and uniformity of dosage. The expression “dosage unit form” as used herein refers to a physically discrete unit of agent appropriate for the subject to be treated. It will be understood, however, that the total daily usage of the compounds, salts, and compositions of the disclosure will be decided by the attending physician within the scope of sound medical judgment. The specific effective dose level for any particular subject or organism will depend upon a variety of factors including the disorder being treated and the severity of the disorder; the activity of the specific compound or salt employed; the specific composition employed; the age, body weight, general health, sex and diet of the subject; the time of administration, route of administration, and rate of excretion of the specific compound or salt employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound or salt employed, and like factors well known in the medical arts. The term “subject” or “patient,” as used herein, means an animal, preferably a mammal.

[0075] The pharmaceutically acceptable compositions of this disclosure can be administered to subjects orally, rectally, parenterally, intracisternally, intravaginally, intraperitoneally, topically (as bypowders, ointments, or drops), bucally, as an oral or nasal spray, or the like, depending on the severity of the condition being treated. In certain embodiments, the compound, salts, and compositions of the disclosure may be administered orally or parenterally at dosage levels of about 0.001 mg / kg to about 1000 mg / kg, one or more times a day, effective to obtain the desired therapeutic effect.

[0076] Liquid dosage forms for oral administration include, but are not limited to, pharmaceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. In addition to the active compound or salt, the liquid dosage forms may contain inert diluents commonly used in the art such as, for example, water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3- butylene glycol, dimethylformamide, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor, and sesame oils), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof. Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

[0077] Injectable preparations, for example, sterile injectable aqueous or oleaginous suspensions may be formulated according to the known art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution, suspension or emulsion in a nontoxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer’s solution, U.S.P. and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil can be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid are used in the preparation of injectables.

[0078] The injectable formulations can be sterilized, for example, by filtration through a bacterial- retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions that can be dissolved or dispersed in sterile water or other sterile injectable medium prior to use.

[0079] In order to prolong the effect of the compounds of the disclosure, it is often desirable to slow the absorption of the compounds from subcutaneous or intramuscular injection. This may be accomplished by the use of a liquid suspension of crystalline or amorphous material with poor water solubility. The rate of absorption of the compound then depends upon its rate of dissolution that, in turn, may depend upon crystal size and crystalline form. Alternatively, delayed absorption of a parenterally administered compound form is accomplished by dissolving or suspending the compound in an oil vehicle. Injectable depot forms are made by forming microencapsule matrices of the compound in biodegradable polymers such as polylactide-polyglycolide. Depending upon the ratio of compound to polymer and the nature of the particular polymer employed, the rate of compound release can becontrolled. Examples of other biodegradable polymers include poly(orthoesters) and poly(anhydrides). Depot injectable formulations are also prepared by entrapping the compound in liposomes or microemulsions that are compatible with body tissues.

[0080] Compositions for rectal or vaginal administration are preferably suppositories which can be prepared by mixing the compound or salt of this disclosure with suitable non-irritating excipients or carriers such as cocoa butter, polyethylene glycol or a suppository wax which are solid at ambient temperature but liquid at body temperature and, therefore, melt in the rectum or vaginal cavity and release the active compound.

[0081] Solid dosage forms for oral administration include capsules, tablets, pills, powders, and granules. In such solid dosage forms, the active compound or salt is mixed with at least one inert, pharmaceutically acceptable excipient or carrier such as sodium citrate or dicalcium phosphate and / or a) fillers or extenders such as starches, lactose, sucrose, glucose, mannitol, and silicic acid, b) binders such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidinone, sucrose, and acacia, c) humectants such as glycerol, d) disintegrating agents such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate, e) solution retarding agents such as paraffin, f) absorption accelerators such as quaternary ammonium compounds, g) wetting agents such as, for example, cetyl alcohol and glycerol monostearate, h) absorbents such as kaolin and bentonite clay, and i) lubricants such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof. In the case of capsules, tablets and pills, the dosage form may also comprise buffering agents.

[0082] Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like. The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings and other coatings well known in the pharmaceutical formulating art. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions that can be used include polymeric substances and waxes. Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like.

[0083] The active compound or salt can also be in microencapsulated form with one or more excipients as noted above. The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings, release-controlling coatings and other coatings well known in the pharmaceutical formulating art. In such solid dosage forms, the active compound orsalt may be admixed with at least one inert diluent such as sucrose, lactose or starch. Such dosage forms may also comprise, as is normal practice, additional substances other than inert diluents, e.g., tableting lubricants and other tableting aids such a magnesium stearate and microcrystalline cellulose. In the case of capsules, tablets and pills, the dosage forms may also comprise buffering agents. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions that can be used include polymeric substances and waxes.

[0084] Dosage forms for topical or transdermal administration of a compound or salt of this disclosure include ointments, pastes, creams, lotions, gels, powders, solutions, sprays, inhalants or patches. The active component is admixed under sterile conditions with a pharmaceutically acceptable carrier and any needed preservatives or buffers as may be required. Ophthalmic formulation, eardrops, and eye drops are also contemplated as being within the scope of this disclosure. Additionally, the disclosure contemplates the use of transdermal patches, which have the added advantage of providing controlled delivery of a compound to the body. Such dosage forms are prepared by dissolving or dispensing the compound in the proper medium. Absorption enhancers can also be used to increase the flux of the compound across the skin. The rate can be controlled by either providing a rate controlling membrane or by dispersing the compound in a polymer matrix or gel.

[0085] As described generally above, the compounds of the disclosure are useful as treatments for parasitic infections and diseases. In one embodiment, the compounds are preventatives of flea and tick infestations. Accordingly, in another aspect, the disclosure provides a method for treating or lessening the severity of a disease, condition, or disorder where a parasite is implicated in the disease state. Synthesis of the Compounds of the Disclosure

[0086] The compounds of the disclosure can be prepared from known materials by the methods described in the Examples, other similar methods, and other methods known to one skilled in the art. As one skilled in the art would appreciate, the functional groups of the intermediate compounds in the methods described below may need to be protected by suitable protecting groups. Protecting groups may be added or removed in accordance with standard techniques, which are well-known to those skilled in the art. The use of protecting groups is described in detail in T.G.M. Wuts et al., Greene’s Protective Groups in Organic Synthesis (4th ed.2006).EXAMPLES General methods.

[0087] All solvents used were commercially available and were used without further purification. Reactions were typically run using anhydrous solvents under an inert atmosphere of nitrogen.

[0088] Proton NMR spectra were recorded using a Bruker plus 400 NMR Spectrometer unless stated otherwise. All deuterated solvents contained typically 0.03% to 0.05% v / v tetramethylsilane, which was used as the reference signal (set at δ 0.00 for both1H and13C).

[0089] Analyses were performed using a Shimadzu HPLC Liquid Chromatography (LC) system, coupled to a Shimadzu LCMS-2020 single quadrupole MS detector. The UV (DAD) acquisition was performed with a scan range of 190-400 nm. The MS was operated with an electro-spray ionization source (ESI) in both positive & negative ion mode. Capillary voltage 0.85 (kV), and desolvation temperature of 250 ºC. Desolvation gas flow 15 (L / min), Cone gas flow 1.5 (L / min). The MS acquisition range was set to 90-900 m / z. MS scan cycle time was 0.4 s. Data acquisition was performed with Shimadzu Lab Solution. Analysis Methods:

[0090] Analytical Method A:

[0091] Column: HALO C182.0 µm, 30 x 3.0 mm; eluent A: H2O + 0.1 vol % TFA, eluent B: CH3CN + 0.05 vol % TFA; gradient: assigned for each compound; flow 1.5 mL / min; temperature: 40°C; PDA scan: 190 - 400 nm.

[0092] Analytical Method B:

[0093] Column: Shim-pack Scepter XR-ODS 2.6 µm, 50 x 3.0 mm; eluent A: H2O + 0.05 vol % NH4HCO3, eluent B: CH3CN; gradient: assigned for each compound; flow 1.2 mL / min; temperature: 40°C; PDA scan: 190 - 400 nm.

[0094] Analytical Method C: Column: Kinetex EVO C18-1002.6 µm, 30 x 3.0 mm; eluent A: H2O + 0.05 vol % NH4HCO3, eluent B: CH3CN; gradient: assigned for each compound; flow 1.5.

[0095] Analytical Method D: Column: Shim‐pack Scepter C18‐1203.0 µm, 33 x 3.0 mm; eluent A: H2O + 0.05% NH4HCO3, eluent B: CH3CN; gradient: assigned for each compound; flow 1.5 mL / min; temperature: 40°C; PDA scan: 190 - 400 nm.

[0096] Analytical Method E: Column: Shim‐pack Scepter C18‐1202.0 µm, 33 x 3.0 mm; eluent A: H2O + 0.05% NH4HCO3, eluent B: CH3CN; gradient: assigned for each compound; flow 1.5 mL / min; temperature: 40°C; PDA scan: 190 - 400 nm.

[0097] Analytical Method F: Column: HALO 90A C182.0 µm, 30 x 3.0 mm; eluent A: H2O + 0.1 vol % FA, eluent B: CH3CN + 0.1 vol % FA; gradient: assigned for each compound; flow 1.2 mL / min; temperature: 40°C; PDA scan: 190 - 400 nm.

[0098] Analytical Method G: Column: HALO 90A C182.0 µm, 30 x 3.0 mm; eluent A: H2O + 0.05 vol % TFA, eluent B: CH3CN + 0.05 vol % TFA; gradient: assigned for each compound; flow 1.2 mL / min; temperature: 40°C; PDA scan: 190 - 400 nm.

[0099] Analytical Method H: Column: HALO C182.7 µm, 30 x 2.1 mm; eluent A: H2O + 0.1 vol % TFA, eluent B: CH3CN + 0.1 vol % TFA; gradient: assigned for each compound; flow 1.5 mL / min; temperature: 40°C; PDA scan: 190 - 400 nm. Abbreviations

[0100] Unless otherwise noted, or where the context dictates otherwise, the following abbreviations shall be understood to have the following meanings: Abbreviation Meaning NMR Nuclear magnetic resonance ESI-MS Electrospray mass spectrometry LCMS Liquid chromatography-mass spectrometry HPLC High performance liquid chromatography SFC Supercritical fluid chromatography GC Gas chromatography ESI Electrospray ionization m / z Mass-to-charge ratio T temperature rt room temperature equiv equivalents kg kilogram G grams mg milligrams L liter(s) mL milliliters μL microliters nL nanoliters mol mole M molarity mmol millimoles h hours min minutes ms millisecond mm millimeters μm micrometers nm nanometerMHz megahertz Hz Hertz J coupling constant s singlet d doublet m multiplet t triplet δ chemical shift Rtretention time N normal (concentration) M molar (concentration) mM millimolar (concentration) μM micromolar (concentration) AcOH acetic acid DAST(diethylamino)sulfur trifluoride DEAdiethylamine DIPEAN-diisopropylethylamine DMF N,N-dimethylformamide DMSO dimethylsulfoxide EtOAc ethyl acetate EtOH ethanol FA formic acid iPrOH iso-propanol HATU 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxid hexafluorophosphate MeOH methanol NCS N-chlorosuccinimide PE petroleum ether TFA trifluoroacetic acid THF tetrahydrofuran Example 1 (S)-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3- yl)-N-(2-((2,2-difluoropropyl)amino)-2-oxoethyl)-2-methylbenzamide (Example 1a) and (R)-4-(5-(5- chloro-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-N-(2- ((2,2-difluoropropyl) amino)-2-oxoethyl)-2-methylbenzamide (Example 1b)Step 1: 4-fluoro-3-(trifluoromethyl)-5-(3,3,3-trifluoroprop-1-en-2-yl) aniline.

[0101] To a solution of 3-bromo-4-fluoro-5-(trifluoromethyl) aniline (30.0 g, 116 mmol) in THF(250 mL) and H2O (60 mL) were added 4,4,6-trimethyl-2-(3,3,3-trifluoroprop-1-en-2-yl)-1,3,2- dioxaborinane (30.9 g, 139 mmol), Cs2CO3(75.8 g, 232 mmol) and Pd(dppf)Cl2(8.51 g, 11.6 mmol). The resulting reaction mixture was stirred at 80°C for 16 h. Upon completion of reaction, the mixture was concentrated under reduced pressure and then extracted with PE. The combined organic layers were washed with H2O (2 x), dried over anhydrous Na2SO4, filtered, and then concentrated under reduced pressure. The crude product was used in the next step without further purification.

[0102] LC-MS (method A): Rt= 0.83 min; MS (ESI+): m / z = 274 (M+H)+. Step 2: methyl (E)-4-((hydroxyimino)methyl)-2-methylbenzoate.

[0103] To a solution of methyl 4-formyl-2-methylbenzoate (50.0 g, 281 mmol) in EtOH (500 mL) were added NH2OH·HCl (23.4 g, 337 mmol) and AcONa (27.6 g, 337 mmol). The resulting mixture was stirred at 60°C for 2 h under nitrogen atmosphere. Upon completion of the reaction, the mixture was allowed to cool down to rt. The precipitated solids were collected by filtration, washed with H2O, and then dried under reduced pressure to afford methyl 4-[(1E)-(hydroxyimino) methyl]-2-methylbenzoate.

[0104] LC-MS (method A): Rt = 0.78 min; MS (ESI+): m / z = 194 (M+H)+. Step 3: methyl (Z)-4-(chloro(hydroxyimino)methyl)-2-methylbenzoate.

[0105] To a solution of methyl 4-[(1E)-(hydroxyimino) methyl]-2-methylbenzoate (50.0 g, 259 mmol) in DMF (400 mL) was added NCS (49.4 g, 311 mmol), and the resulting reaction mixture was stirred at rt for 1 h. The mixture was used in the next step.

[0106] LC-MS (method A): Rt = 0.96 min; MS (ESI+): m / z = 228 (M+H)+. Step 4: rac-methyl-4-(5-(5-amino-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5- dihydroisoxazol-3-yl)-2-methylbenzoate.

[0107] To a stirred solution of methyl (Z)-4-(chloro(hydroxyimino)methyl)-2-methylbenzoate (crude) in DMF (400 mL) were added 4-fluoro-3-(trifluoromethyl)-5-(3,3,3-trifluoroprop-1-en-2-yl) aniline (crude) and DIEA (66.8 g, 518 mmol) dropwise at rt. Then, the resulting mixture was stirred at rt for 2 h. Upon completion of the reaction, H2O (1 L) was added, and the resulting mixture was extracted with EtOAc (3 x). The combined organic layers were washed with H2O (6 x), brine, dried over anhydrous Na2SO4 and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (EtOAc / PE ~17 / 100) to afford 4-(5-(5-amino-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)- 4,5-dihydroisoxazol-3-yl)-2-methylbenzoate.

[0108] LC-MS (method A): Rt= 0.94 min; MS (ESI+): m / z = 465 (M+H)+.1H NMR (400 MHz, DMSO-d6): δ [ppm] = 7.89-7.88 (m, 1H), 7.78-7.69 (m, 2H), 7.19-7.17 (m, 1H), 6.98-6.96 (m, 1H), 5.76- 5.74 (m, 2H), 4.43 (d, 1H), 4.19 (d, 1H), 3.85 (s, 3H), 2.56 (s, 3H).Step 5: 4-(5-(5-amino-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol- 3-yl)-2-methylbenzoic acid.

[0109] To solution of rac-methyl 4-(5-(5-amino-2-fluoro-3-(trifluoromethyl) phenyl)-5- (trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2-methylbenzoate (76.0 g, 163 mmol) in THF (400 mL) was added LiOH (18.8 g, 817 mmol) in H2O (150 mL). The resulting mixture was stirred at 60°C for 16 h. Upon completion of the reaction, the solvent was evaporated under reduced pressure, and the pH of the solution was adjusted to 4 (HCl, 2 M). The aqueous phase was extracted with EtOAc (2 x). The combined organic layers were washed with H2O (3 x), brine , dried over anhydrous Na2SO4 and concentrated in vacuo to afford rac-4-(5-(5-amino-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3- yl)-2-methylbenzoic acid (95% yield).

[0110] LC-MS (method A): Rt =0.63 min; MS (ESI+): m / z = 451 (M+H)+.1H NMR (400 MHz, DMSO-d6): δ [ppm] = 13.05 (s, 1H), 7.88 (d, J = 8.1 Hz, 1H), 13.01 (br, 1H), 7.88 (d, 1H), 7.71-7.68 (m, 2H), 7.19-7.17 (m, 1H), 5.75-5.73 (br, 2H), 4.47-4.16 (m, 2H), 2.56 (s, 3H). Step 6: rac-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5- dihydroisoxazol-3-yl)-2-methylbenzoic acid.

[0111] To a solution of rac-4-(5-(5-amino-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)- 4,5-dihydroisoxazol-3-yl)-2-methylbenzoic acid (50.0 g, 111 mmol) in AcOH (550 mL) were added conc. HCl (138 mL) and NaNO2 (10.9 g, 159 mmol) in H2O (~10 mL) at 0°C. The reaction was stirred by mechanical stirrer at 0°C for 15 min, then CuCl (24.2 g, 222 mmol) was added in portions at 0°C, and the resulting mixture was stirred at rt overnight. Upon completion of the reaction, H2O (800 mL) was added, and the mixture was extracted with EtOAc (2 x). The combined organic layers were washed with H2O (4 x), dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (EtOAc / PE, ~13 / 100), and then by reverse phase C18 column chromatography [column: C18, 330 g; mobile phase A: H2O (0.1% FA), mobile phase B: CH3CN; flow rate: 100 mL / min; gradient: 5% B to 60 % B in 30 min; wave length: 254 / 220 nm] to afford rac-4-(5- (5-chloro-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2- methylbenzoic acid (39% yield).

[0112] LC-MS (method B): Rt= 1.0 min; MS (ESI+): m / z = 470 (M+H)+. Step 7: (S)-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5- dihydroisoxazol-3-yl)-2-methylbenzoic acid.

[0113] The racemic mixture was separated by chiral-SFC [column: CHIRAL ART Cellulose-SB 5*25 cm, 10 µm; mobile phase A: CO2, mobile phase B: iPrOH (+ 0.1% FA); flow rate: 146 mL / min; gradient: isocratic 20% B; temperature: 35°C; back pressure: 100 bar; wave length: 220 nm; Rt1 = 3.4 min;Rt2= 4.1 min] to afford (S)-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5- dihydroisoxazol-3-yl)-2-methylbenzoic acid (ee value: >99%).

[0114] LC-MS (method C): Rt= 1.1 min; MS (ESI+): m / z = 68 (M-H)+. Step 8: tert-butyl (2-((2,2-difluoropropyl) amino)-2-oxoethyl) carbamate.

[0115] To a solution of (tert-butoxycarbonyl) glycine (20.0 g, 114 mmol) in DMF (120 mL) were added HATU (52.1 g, 137 mmol), DIEA (58.9 g, 457 mmol) and 2,2-difluoropropan-1-amine hydrochloride (18.0 g, 137 mmol). Then the resulting mixture was stirred at rt for 4 h. Upon completion of the reaction, H2O (400 mL) was added, and the resulting mixture was extracted with EtOAc (2 x). The combined organic layers were washed with H2O (6 x), brine, dried over anhydrous Na2SO4, filtered, and then concentrated under reduced pressure. The residue was purified by reverse phase C18 column chromatography [column: C18, 330 g; mobile phase A: H2O (10 mmol / L NH4HCO3), mobile phase B: CH3CN; flow rate: 100 mL / min; gradient: 5% B to 70 % B in 30 min; wave length: 200 nm] to afford tert-butyl (2-((2,2-difluoropropyl) amino)-2-oxoethyl) carbamate (96% yield).

[0116] 1H NMR (400 MHz, DMSO-d6): δ [ppm] = 8.16 (t, 1H), 6.97 (t, 1H), 3.60-3.46 (m, 4H), 1.57 (t, 3H), 1.38 (s, 9H). LC-MS (method C): Rt = 0.70 min; MS (ESI+): m / z = 253 (M+H)+. Step 9: 2-amino-N-(2,2-difluoropropyl) acetamide hydrochloride.

[0117] To a solution of tert-butyl (2-((2,2-difluoropropyl) amino)-2-oxoethyl) carbamate (28.0 g, 111 mmol) in dioxane (200 mL) was added HCl (80 mL). The resulting mixture was stirred at rt for 3 h. Upon completion of the reaction, the solvent was removed in vacuo, and the residue was triturated with EtOAc (200 mL) to afford 2-amino-N-(2,2-difluoropropyl) acetamide hydrochloride (62% yield).

[0118] 1H NMR (400 MHz, DMSO-d6): δ [ppm] = 8.95 (t, 1H), 8.31 (s, 3H), 3.663.53 (m, 4H), 1.66 (s, 1H), 1.61 (s, 1H), 1.56 (s, 1H). LC-MS (method C): Rt = 0.17 min; MS (ESI+): m / z = 153 (M+H)+. Step 10: (S)-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl) phenyl)-5-(trifluoromethyl)-4,5- dihydroisoxazol-3-yl)-N-(2-((2,2-difluoropropyl) amino)-2-oxoethyl)-2-methylbenzamide.

[0119] To a stirred solution of (S)-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl) phenyl)-5- (trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2-methylbenzoic acid (20.0 g, 42.6) in DMF (100 mL) were added HATU (19.4 g, 51.1 mmol), DIEA (27.5 g, 213 mmol) and 2-amino-N-(2,2-difluoropropyl) acetamide hydrochloride (9.45 g, 51.1 mmol). Then, the resulting mixture was stirred at rt for 3 h. Upon completion of the reaction, H2O (600 mL) was added, and the resulting mixture was extracted with EtOAc (3 x). The combined organic layers were washed with H2O (6 x), brine, dried over anhydrous Na2SO4, filtered, and then concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (EtOAc / hexanes, ~53:100) to afford Example 1a (81% yield) as a colorlesssolid. XRPD showed that the product was crystalline samples.

[0120] LC-MS (method C, 0.01-1.20 min 10-90% B, 1.20-1.80 min 90% B, 1.80-1.82 min 90-10%): Rt= 1.1 min; MS (ESI+): m / z = 604 (M+H)+.1H NMR (400 MHz, DMSO-d6): δ [ppm] = 8.60 (t, J = 5.6 Hz, 1H), 8.37 (t, J = 6.0 Hz, 1H), 8.15-8.14 (m, 1H), 8.03-8.01 (m, 1H), 7.67-7.65 (m, 2H), 7.51-7.48 (m, 1H), 4.57-4.37 (m, 2H), 3.90 (d, J = 5.6 Hz, 2H), 3.62-3.53 (m, 2H), 2.41 (s, 3H), 1.58 (t, 3H).

[0121] Example 1b was prepared analogously by the methodology described for Example 1a.

[0122] 1H NMR (400 MHz, DMSO-d6): δ [ppm] = 8.60 (t, J = 5.6 Hz, 1H), 8.37 (t, J = 6.0 Hz, 1H), 8.15-8.14 (m, 1H), 8.03-8.01 (m, 1H), 7.67-7.65 (m, 2H), 7.51-7.48 (m, 1H), 4.57-4.37 (m, 2H), 3.90 (d, J = 5.6 Hz, 2H), 3.62-3.53 (m, 2H), 2.41 (s, 3H), 1.58 (t, 3H). Example 2 (S)-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3- yl)-N-(2-((2-fluoro-2-methylpropyl)amino)-2-oxoethyl)-2-methylbenzamide (Example 2a) and (R)-4- (5-(5-chloro-2-fluoro-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-N-(2- ((2-fluoro-2-methylpropyl)amino)-2-oxoethyl)-2-methylbenzamide (Example 2b)Step 1: tert-butyl (2-((2-fluoro-2-methylpropyl)amino)-2-oxoethyl)carbamate.

[0123] To a solution of 2-(tert-butoxycarbonylamino)acetic acid (1.8 g, 10.3 mmol) in DMF were added 2-fluoro-2-methyl-propan-1-amine hydrochloride (1.31 g, 10.3 mmol), HATU (3.91 g, 10.3 mmol) and DIPEA (1.33 g, 10.3 mmol, 1.79 mL). The mixture was stirred for 1 h at rt. Then the mixture was treated with H2O and extracted with EtOAc. The organic layer was dried over anhydrous Na2SO4. After filtration, the solvent was evaporated under reduced pressure, and the resulting residue was purified by prep-HPLC [column: XBridge prep-OBD C18 column, 30*150 mm, 5 μm; mobile phase A: H2O (10 mmol / L FA), mobile phase B: CH3CN; flow rate: 60 mL / min; gradient: 57% B to 87% B in 7 min] to afford tert-butyl N-[2-[(2-fluoro-2-methyl-propyl)amino]-2-oxo-ethyl]carbamate (78% yield) as a brownish oil.

[0124] MS (ESI+): m / z = 249 (M+H)+. Step 2: 2-amino-N-(2-fluoro-2-methylpropyl)acetamide.

[0125] To a solution of tert-butyl N-[2-[(2-fluoro-2-methyl-propyl)amino]-2-oxo-ethyl]carbamate(200 mg, 805 μmol) in CH2Cl2(2 mL) was added TFA (1 mL). The mixture was stirred for 3 h at rt, before it was concentrated under reduced pressure to get 2-amino-N-(2-fluoro-2-methyl-propyl)acetamide as a brownish oil.

[0126] MS (ESI+): m / z = 149 (M+H)+. Step 3: (S)-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5- dihydroisoxazol-3-yl)-N-(2-((2-fluoro-2-methylpropyl)amino)-2-oxoethyl)-2-methylbenzamide.

[0127] To a solution of 4-[(5S)-5-[5-chloro-2-fluoro-3-(trifluoromethyl)phenyl]-5-(trifluoromethyl)- 4H-isoxazol-3-yl]-2-methyl-benzoic acid (50.0 mg, 106 μmol) in DMF (1 mL) were added 2-amino-N-(2- fluoro-2-methyl-propyl)acetamide (24.0 mg, 160 μmol), HATU (49 mg, 128 μmol) and DIPEA (69.0 mg, 532 μmol, 92.7 μL).The mixture was stirred at rt for 1 h. H2O was added, and the mixture was extracted with EtOAc (3 x). The combined organic layers were washed with H2O, and then concentrated under reduced pressure. The crude product was purified by prep-HPLC [column: XBridge prep-OBD C18 Column, 30*150 mm, 5μm; mobile phase A: H2O (10 mmol / L NH4HCO3 + 0.05%NH3·H2O), mobile phase B: CH3CN; flow rate: 60 mL / min; gradient: 24% B to 54% B in 8 min; wave length: 254 / 220 nm; Rt = 6.9 min] to afford 4-[(5S)-5-[5-chloro-2-fluoro-3-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H- isoxazol-3-yl]-N-[2-[(2-fluoro-2-methyl-propyl)amino]-2-oxo-ethyl]-2-methyl-benzamide (34% yield) as a colorless solid.

[0128] LC-MS (method D, 0.01-1.20 min 40-95% B, 1.20-1.80 min 95% B): Rt = 1.0 min; MS (ESI+): m / z = 600 (M+H)+.1H-NMR (400 MHz, CDCl3): δ [ppm] = 8.07-8.04 (m, 1H), 7.73-7.71 (m, 1H), 7.59- 7.48 (m, 3H), 6.62-6.57 (m, 1H), 6.28-6.20 (m, 1H), 4.22-4.18 (m, 3H), 3.88 (d, 1H), 3.55-3.48 (m, 2H), 2.52 (s ,3H), 1.42 (s, 3H), 1.37 (s, 3H). Step 4: (R)-4-(5-(5-chloro-2-fluoro-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5- dihydroisoxazol-3-yl)-N-(2-((2-fluoro-2-methylpropyl)amino)-2-oxoethyl)-2-methylbenzamide.

[0129] To a solution of 4-[(5R)-5-[5-chloro-2-fluoro-3-(trifluoromethyl)phenyl]-5-(trifluoromethyl)- 4H-isoxazol-3-yl]-2-methyl-benzoic acid (50.0 mg, 106 μmol) in DMF (1 mL) were added 2-amino-N-(2- fluoro-2-methyl-propyl)acetamide (24.0 mg, 160 μmol), HATU (49.0 mg, 128 μmol) and DIPEA (69.0 mg, 532 μmol, 92.7 μL). The mixture was stirred at rt for 1 h. H2O was added, and the resulting mixture was extracted with EtOAc (3 x). The combined organic layers were washed with H2O and concentrated under reduced pressure. The crude product was purified via prep-HPLC [column: XBridge prep-OBD C18 column, 30*150 mm, 5 μm; mobile phase A: H2O (10 mmol / L NH4HCO3+ 0.05%NH3·H2O), mobile phase B: CH3CN; flow rate: 60 mL / min mL / min; gradient: 35% B to 65% B in 8 min; wave length: 254 / 220 nm; Rt= 7.5 min] to afford Example 2a (24% yield) as a colorless solid.

[0130] LC-MS (method D, 0.01-1.20 min 40-95% B, 1.20-1.80 min 95% B): Rt= 1.0 min; MS (ESI+):m / z = 600 (M+H)+.1H NMR (400 MHz, CDCl3): δ [ppm] = 8.07-8.05 (m, 1H), 7.73-7.71 (m, 1H), 7.58- 7.51 (m, 3H), 6.59-6.54 (m, 1H), 6.23-6.17 (m, 1H), 4.23-4.18 (m, 3H), 3.88 (d, 1H), 3.55-3.48 (m, 2H), 2.53 (s, 3H), 1.42 (s, 3H), 1.37 (s, 3H).

[0131] Example 2b was prepared analogously by the methodology described for Example 2a.

[0132] 1H NMR (400 MHz, CDCl3): δ [ppm] = 8.07-8.05 (m, 1H), 7.73-7.71 (m, 1H), 7.58-7.51 (m, 3H), 6.59-6.54 (m, 1H), 6.23-6.17 (m, 1H), 4.23-4.18 (m, 3H), 3.88 (d, 1H), 3.55-3.48 (m, 2H), 2.53 (s, 3H), 1.42 (s, 3H), 1.37 (s, 3H). Example 3 (S)-4-(5-(5-cyano-2-fluoro-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)- N-(2-((2,2-difluoropropyl)amino)-2-oxoethyl)-2-methylbenzamide (Example 3)

[0133] To a solution of 4-[(5S)-5-[5-chloro-2-fluoro-3-(trifluoromethyl)phenyl]-5-(trifluoromethyl)- 4H-isoxazol-3-yl]-N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-benzamide (60.0 mg, 100 μmol) in H2O (0.1 mL) and 1,4-dioxane (0.4 mL) were added XPhos (10.0 mg, 20.0 μmol), Pd2(dba)3(18.0 mg, 20.0 μmol) and tetrapotassium hexacyanoferrate trihydrate (111 mg, 300 μmol). The reaction mixture was stirred for 2 h at 80°C under nitrogen atmosphere. After this time, the reaction was allowed to cool down to rt, was treated with H2O, and then extracted with EtOAc (3x). The combined organic layers were dried over anhydrous Na2SO4, filtered, and then concentrated under reduced pressure. The crude product was further purified by prep-HPLC [column: YMC-Actus Triart C18ExRs, 30*150 mm, 5 μm; mobile phase A: H2O (10 mmol / L NH4HCO3), mobile phase B: CH3CN; flow rate: 60 mL / min; gradient: 48% B to 78% B in 7 min] to afford 4-[(5S)-5-[5-cyano-2-fluoro-3-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H- isoxazol-3-yl]-N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-benzamide (50% yield) as a colorless solid.

[0134] LC-MS (method E, 0.01-1.70 min 30-70% B, 1.70-2.30 min 70-95% B, 2.30-2.80 min 95% B): Rt = 1.59 min; MS (ESI+): m / z = 595 (M+H)+.1H NMR (400 MHz, CDCl3): δ [ppm] = 8.41 (d, 1H), 8.07 (d, 1H), 7.58-7.56 (m, 2H), 7.52 (d, 1H), 6.63-6.58 (d, 1H), 6.40-6.35 (m, 1H), 4.27-4.19 (m, 3H), 3.89 (d, 1H), 3.78-3.70 (td, 2H), 2.52 (s, 3H).1.66 (t, 3H).Example 4 (S)-4-(5-(5-cyano-2-fluoro-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)- N-(2-((2-fluoro-2-methylpropyl)amino)-2-oxoethyl)-2-methylbenzamide (Example 4)

[0135] To a solution of 4-[(5S)-5-[5-chloro-2-fluoro-3-(trifluoromethyl)phenyl]-5-(trifluoromethyl)- 4H-isoxazol-3-yl]-N-[2-[(2-fluoro-2-methyl-propyl)amino]-2-oxo-ethyl]-2-methyl-benzamide (60.0 mg, 100 μmol) in H2O (0.1 mL) and dioxane (0.4 mL) were added XPhos (10.0 mg, 20.0 μmol), Pd2(dba)3 (18.3 mg, 20.0 μmol) and tetrapotassium hexacyanoferrate trihydrate (111 mg, 300 μmol). The reaction mixture was stirred for 2 h at 80°C under nitrogen atmosphere. After this time, the reaction was allowed to cool down to rt, was treated with H2O, and then extracted with EtOAc (3x). The combined organic layers were dried over anhydrous Na2SO4, filtered, and then concentrated under reduced pressure. The crude product was further purified by prep-HPLC [column: YMC-Actus Triart C18ExRs, 30*150 mm, 5 μm; mobile phase A: H2O (10 mmol / L NH4HCO3), mobile phase B: CH3CN; flow rate: 60 mL / min; gradient: 48% B to 78% B in 7 min] to afford 4-[(5S)-5-[5-cyano-2-fluoro-3-(trifluoromethyl)phenyl]-5-(trifluoromethyl)- 4H-isoxazol-3-yl]-N-[2-[(2-fluoro-2-methyl-propyl)amino]-2-oxo-ethyl]-2-methyl-benzamide (16% yield) as a colorless solid.

[0136] LC-MS (method D, 0.01-1.20 min 10-95% B, 1.20-1.80 min 95% B): Rt= 1.127 min; MS (ESI+): m / z = 591 (M+H)+.1H NMR (400 MHz, CDCl3): δ [ppm] = 8.41 (d, 1H), 8.07 (d, 1H), 7.58-7.52 (m, 3H), 6.58-6.55 (m, 1H), 6.19-6.15 (m, 1H), 4.27-4.18 (m, 3H), 3.89 (d, 1H), 3.56-3.49 (m, 2H), 2.53 (s, 3H), 1.43 (s, 6H), 1.37 (s, 3H). Example 5 N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-4-[rel-(5S)-5-(3,5-dichloro-2-fluoro-phenyl)- 5-(trifluoromethyl)-4H-isoxazol-3-yl]benzamide (Example 5a) and N-[2-(2,2-difluoropropylamino)- 2-oxo-ethyl]-2-methyl-4-[rel-(5R)-5-(3,5-dichloro-2-fluoro-phenyl)-5-(trifluoromethyl)-4H-isoxazol- 3-yl]benzamide (Example 5b)Step 1: 1,5-dichloro-2-fluoro-3-(3,3,3-trifluoroprop-1-en-2-yl)benzene.

[0137] A mixture of (3,5-dichloro-2-fluoro-phenyl)boronic acid (1.90 g, 8.64 mmol), 2-bromo-3,3,3- trifluoro-prop-1-ene (2.27 g, 13.0 mmol, 1.35 mL), Pd(dppf)Cl2(705 mg, 864 µmol) and Cs2CO3(8.45 g, 25.9 mmol) in toluene (15 mL) was stirred for 16 h at 80°C under nitrogen atmosphere. The mixture was allowed to cool down to rt. Then, the mixture was extracted with hexanes, and the resulting solution was used in the next step without further purification.

[0138] GCMS (ESI+): m / z = 258 (M)+. Step 2: methyl 4-(5-(3,5-dichloro-2-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2- methylbenzoate.

[0139] To a stirred solution of methyl 4-[(E)-hydroxyiminomethyl]-2-methyl-benzoate (1.40 g, 7.25 mmol) in DMF (12 mL) was added NCS (1.45 g, 10.9 mmol) portion wise at rt. The resulting mixture was stirred for 1 h at 40°C. To the above mixture was added 1,5-dichloro-2-fluoro-3-[1- (trifluoromethyl)vinyl] benzene (2.68 g, 7.25 mmol) and DIEA (4.68 g, 36.2 mmol) dropwise at 0°C. Then, the resulting mixture was stirred for additional 1 h at rt. After this time, the mixture was treated with H2O and extracted with EtOAc (3 x). The combined organic layers were washed with brine, dried over anhydrous Na2SO4 and concentrated in vacuo. The residue was purified by column chromatography on silica gel (0- 50% EtOAc in PE) to afford methyl 2-methyl-4-[rac-(5R)-5-(3,5-dichloro-2-fluoro-phenyl)-5- (trifluoromethyl)-4H-isoxazol-3-yl]benzoate (30% yield) as a yellowish oil.

[0140] GCMS (ESI+): m / z = 449 (M)+. Step 3: 4-(5-(3,5-dichloro-2-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2- methylbenzoic acid.

[0141] A mixture of methyl 2-methyl-4-[rac-(5R)-5-(3,5-dichloro-2-fluoro-phenyl)-5- (trifluoromethyl)-4H-isoxazol-3-yl]benzoate (1.10 g, 2.20 mmol) and LiOH (527 mg, 22.0 mmol) in THF (10 mL) and H2O (10 mL) was stirred for 4 h at 50°C. After this time, the mixture was acidified to pH ~ 7 with HCl (1 M) and poured into H2O. The aqueous layer was separated and extracted with EtOAc (3 x). The combined organic layers were washed with brine, dried over anhydrous Na2SO4and filtered, and concentrated under reduced pressure to afford 2-methyl-4-[rac-(5R)-5-(3,5-dichloro-2-fluoro-phenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]benzoic acid (94% yield).

[0142] LC-MS (method F, 0.01-1.00 min 5-100% B, 1.00-1.40 min 100% B): Rt= 1.034 min; MS (ESI+): m / z = 436 (M+H)+. Step 4: N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-4-[rel-(5S)-5-(3,5-dichloro-2-fluoro- phenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]benzamide (Example 5a) and N-[2-(2,2- difluoropropylamino)-2-oxo-ethyl]-2-methyl-4-[rel-(5R)-5-(3,5-dichloro-2-fluoro-phenyl)-5- (trifluoromethyl)-4H-isoxazol-3-yl]benzamide (Example 5b).

[0143] A mixture of 4-[5-(3,5-dichloro-2-fluoro-phenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]-2- methyl-benzoic acid (400 mg, 825 μmol), 2-amino-N-(2,2-difluoropropyl)acetamide (177 mg, 990 μmol) and DIEA (533 mg, 4.13 mmol) in CH2Cl2 (5 mL) was stirred for 10 min at rt. To the above mixture was added T3P (394 mg, 1.24 mmol) at rt. The resulting mixture was stirred for 1 h at rt. After this time, the mixture was poured into H2O and extracted with CH2Cl2 (3 x). The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The crude product was purified by column chromatography on silica gel (0-50% EtOAc in PE) to afford the racemic product. The two enantiomers were separated by chiral-SFC [column: CHIRAL ART Cellulose-SB, 2*25 cm, 5 μm; mobile phase A: hexanes, mobile phase B: EtOH; flow rate: 20 mL / min; gradient: isocratic 15; wave length: 254 / 220 nm; Rt1 = 12.2 min; Rt2 = 14.4 min] to afford N-[2-(2,2-difluoropropylamino)-2-oxo- ethyl]-2-methyl-4-[rel-(5S)-5-(3,5-dichloro-2-fluoro-phenyl)-5-(trifluoromethyl)-4H-isoxazol-3- yl]benzamide (23% yield) and N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-4-[rel-(5R)-5-(3,5- dichloro-2-fluoro-phenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]benzamide (24% yield).

[0144] Example 5a: LC-MS (method G, 0.01-1.70 min 30-70% B, 1.70-2.30 min 70-95% B, 2.30- 2.8095% B): Rt = 1.483 min; MS (ESI+): m / z = 570 (M+H)+.1H NMR (400 MHz, DMSO-d6): δ [ppm] = 8.60 (t, 1H), 8.36 (t, 1H), 8.06-8.04 (m, 1H), 7.70-7.61 (m, 3H), 7.49 (d, 1H), 4.57-4.22 (m, 2H), 3.90 (d, 2H), 3.56-3.52 (m, 2H), 2.40 (s, 3H), 1.58 (t, 3H).

[0145] Example 5b: LC-MS (method G, 0.01-1.70 min 30-70% B, 1.70-2.30 min 70-95% B, 2.30- 2.8095% B): Rt = 1.482 min; MS (ESI+): m / z = 570 (M+H)+.1H NMR (400 MHz, DMSO-d6): δ [ppm] = 8.60 (t, 1H), 8.36 (t, 1H), 8.06-8.04 (m, 1H), 7.70–7.62 (m, 3H), 7.49 (d, 1H), 4.56–4.28 (m, 2H), 3.90 (d, 2H), 3.62-3.57 (m, 2H), 2.40 (s, 3H), 1.58 (t, 3H). Example 6 N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-4-[rel-(5S)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)- 4H-isoxazol-3-yl]-2-(trifluoromethyl)benzamide (Example 6a) and N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-4-[rel-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)- 4H-isoxazol-3-yl]-2-(trifluoromethyl)benzamide (Example 6b)Step 1: 1,3-dichloro-5-[1-(trifluoromethyl)vinyl] benzene.

[0146] To a solution of 1-bromo-3,5-dichloro-benzene (10.0 g, 44.3 mmol) in THF (100 mL) and H2O (25 mL) were added 4,4,6-trimethyl-2-[1-(trifluoromethyl) vinyl]-1,3,2-dioxaborinane (11.8 g, 53.1 mmol), Cs2CO3(28.9 g, 88.5 mmol) and Pd(dppf)Cl2(3.62 g, 4.43 mmol). Then the resulting mixture was stirred at 80°C for 16 h under nitrogen atmosphere. Upon completion of reaction, the mixture was allowed to cool down to rt and was then concentrated under reduced pressure. H2O was added, and the mixture was extracted with PE (3 x). The combined organic layers were washed with H2O, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The crude product was used in the next step without further purification.

[0147] GCMS (ESI+): m / z = 240 (M)+. Step 2: methyl 4-[(E)-hydroxyiminomethyl]-2-(trifluoromethyl) benzoate.

[0148] To a solution of methyl 4-formyl-2-(trifluoromethyl) benzoate (5.00 g, 21.5 mmol) in EtOH (50 mL) were added NH2OH·HCl (1.80 g, 25.8 mmol) and AcONa (2.12 g, 25.8 mmol). The resulting mixture was stirred at 60°C for 2 h under nitrogen atmosphere. Upon completion of the reaction, the mixture was allowed to cool down to rt. The precipitated solids were collected by filtration, washed with H2O, and then dried in vacuo to afford methyl 4-[(E)-hydroxyiminomethyl]-2-(trifluoromethyl) benzoate.

[0149] LC-MS (method F, 0.01-1.10 min 5-100% B, 1.10-1.40 min 100% B): Rt = 0.67 min; MS (ESI+): m / z = 248 (M+H)+. Step 3: methyl 4-[(Z)-C-chloro-N-hydroxy-carbonimidoyl]-2-(trifluoromethyl) benzoate.

[0150] To a solution of methyl 4-[(E)-hydroxyiminomethyl]-2-(trifluoromethyl) benzoate (5.13 g, 20.8 mmol) in DMF (50 mL) was added NCS (3.33 g, 24.9 mmol), and the reaction mixture was stirred at rt for 1 h. The resulting mixture was used in the next step directly without further operation. Step 4: methyl 4-[rac-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]-2- (trifluoromethyl)benzoate.

[0151] To a stirred solution of methyl 4-[(Z)-C-chloro-N-hydroxy-carbonimidoyl]-2-(trifluoromethyl) benzoate (crude) in DMF (50 mL) were added 1,3-dichloro-5-[1-(trifluoromethyl) vinyl] benzene (crude)and DIEA (4.70 g, 36.4 mmol) dropwise at rt. Then the resulting mixture was stirred at rt for 2 h. Upon completion of the reaction, H2O was added, and the resulting mixture was extracted with EtOAc (3 x). The combined organic layers were washed with H2O, brine, dried over anhydrous Na2SO4and concentrated under reduced pressure. The crude product was purified by column chromatography on silica gel (0-20% EtOAc in PE) to afford methyl 4-[rac-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]- 2-(trifluoromethyl)benzoate.

[0152] LC-MS (method F, 0.01-1.10 min 5-100% B, 1.10-1.40 min 100% B): Rt= 1.1 min; MS (ESI+): m / z = 484 (M-H)-. Step 5: 4-[rac-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]-2- (trifluoromethyl)benzoic acid.

[0153] To a solution of methyl 4-[rac-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H-isoxazol- 3-yl]-2-(trifluoromethyl) benzoate (2.00 g, 4.11 mmol) in THF (16 mL) was added LiOH (493 mg, 20.6 mmol) in H2O (8 mL). The resulting mixture was stirred at 60°C for 16 h. Upon completion of the reaction, the solvent was evaporated under reduced pressure, and the pH value of resulting mixture was adjusted to 4 (with HCl (2 M)). The mixture was extracted with EtOAc (3 x), and the combined organic layers were washed with H2O and brine, dried over anhydrous Na2SO4 and concentrated under reduced pressure to afford 4-[rac-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]-2-(trifluoromethyl) benzoic acid.

[0154] LC-MS (method F, 0.01-1.10 min 5-100% B, 1.10-1.40 min 100% B): Rt = 0.99 min; MS (ESI+): m / z = 470 (M-H)-. Step 6: N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-4-[rel-(5S)-5-(3,5-dichlorophenyl)-5- (trifluoromethyl)-4H-isoxazol-3-yl]-2-(trifluoromethyl) benzamide (Example 6a) and N-[2-(2,2- difluoropropylamino)-2-oxo-ethyl]-4-[rel-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H- isoxazol-3-yl]-2-(trifluoromethyl)benzamide (Example 6b).

[0155] To a stirred solution of 4-[rac-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H-isoxazol-3- yl]-2-(trifluoromethyl)benzoic acid (200 mg, 424 μmol) in DMF (2 mL) were added HATU (193 mg, 508 μmol), DIEA (273 mg, 2.12 mmol) and 2-amino-N-(2,2-difluoropropyl)acetamide (77.3 mg, 508 μmol). The resulting mixture was stirred at rt for 1 h. After this time, H2O was added, and the resulting mixture was extracted with EtOAc (3 x). The combined organic layers were washed with H2O and brine, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by prep- TLC (EtOAc / PE 2:1), and the two enantiomers were separated by chiral HPLC [column: CHIRAL ART Cellulose-SJ 3*25 cm, 5 µm; mobile phase A: CO2, mobile phase B: MeOH (+ 1% 2 M NH3·MeOH); flow rate: 90 mL / min; gradient: isocratic 14% B; temperature: 35°C; back pressure: 100 bar; wave length: 220nm; Rt1= 3.6 min; Rt2= 4.4 min] to afford N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-4-[rel-(5S)-5-(3,5- dichlorophenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]-2-(trifluoromethyl)benzamide (28% yield) and N- [2-(2,2-difluoropropylamino)-2-oxo-ethyl]-4-[rel-(5R)-5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H- isoxazol-3-yl]-2-(trifluoromethyl)benzamide (31% yield).

[0156] Example 6a: LC-MS (method C, 0.01-1.20 min 10-90% B, 1.20-1.80 min 90% B, 1.80-1.82 min 90-10%): Rt= 0.98 min; MS (ESI+): m / z = 606 (M+H)+.1H NMR (400 MHz, DMSO-d6): δ [ppm] = 8.90 (t, 1H), 8.37 (t, 1H), 8.10 (d, 1H), 8.04 (s, 1H), 7.83 (t, 1H), 7.73 (d, 1H), 7.64 (d, 2H), 4.56-4.38 (m, 2H), 3.92 (d, 2H), 3.65-3.52 (m, 2H), 1.58 (t, 3H).

[0157] Example 6b: LC-MS (method C, 0.01-1.20 min 10-90% B, 1.20-1.80 min 90% B, 1.80-1.82 min 90-10%): Rt = 0.98 min; MS (ESI+): m / z = 606 (M+H)+.1H NMR (400 MHz, DMSO-d6): δ [ppm] = 8.90 (t, 1H), 8.37 (t, 1H), 8.10 (d, 1H), 8.04 (s, 1H), 7.83 (s, 1H), 7.73 (d, 1H), 7.64 (d, 2H), 4.56-4.38 (m, 2H), 3.92 (d, 2H), 3.65-3.52 (m, 2H), 1.58 (t, 3H). Example 7 (S)-4-(5-(3-chloro-2-fluoro-5-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3- yl)-N-(2-((2,2-difluoropropyl)amino)-2-oxoethyl)-2-methylbenzamide (Example 7a ) and (R)-4-(5-(3- chloro-2-fluoro-5-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-N-(2-((2,2- difluoropropyl)amino)-2-oxoethyl)-2-methylbenzamide (Example 7b)Step 1: 1-chloro-2-fluoro-5-(trifluoromethyl)-3-[1-(trifluoromethyl)vinyl]benzene.

[0158] To a solution of [3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-(hydroxymethyl)borinic acid (30 g, 117.01 mmol) in THF (300 mL) and H2O (75 mL) was added 2-bromo-3,3,3-trifluoro-prop-1-ene (24.56 g, 140.41 mmol, 14.57 mL) , cyclopentyl(diphenyl)phosphane; dichloropalladium; iron (8.56 g, 11.70 mmol) and dicesium; carbonate (76.25 g, 234.02 mmol) . The reaction mixture was stirred at 80 ℃ for 16 h. After filtration, the filtrate was concentrated under reduced pressure. The crude product was purified via silica gel column chromatography, eluted with ethyl acetate in petroleum ether from 0% to 60% to afford to get 1-chloro-2-fluoro-5-(trifluoromethyl)-3-[1-(trifluoromethyl)vinyl]benzene (25 g, 85.45 mmol, 73.03% yield) as a yellow oil. Step 2: Methyl 4-[(E)-hydroxyiminomethyl]-2-methyl-benzoate

[0159] To a solution of methyl 4-formyl-2-methylbenzoate (200.00 g, 1122.40 mmol) in 2-Me-THF(2.0 L, 10 V) were added with NH2OH.HCl (93.59 g, 1346.88 mmol, 1.2 eq.) and AcONa (110.48 g, 1346.88 mmol, 1.2 eq.). Then the resulting mixture was stirred at 70°C for 1 h. Sample was taken for IPC (by HPLC analysis), the criterion was: starting material ≤1.0% (results：starting material= N.D.). Upon completion of the reaction, the mixture was allowed to cool down to 25°C. H2O (2.0 L, 10 V) was added to the reactor, then the resulting mixture was stirred at 25°C for 1 h. The mixture was settled and separated to collect the organic phase. The organic phase was concentrated to no obvious fraction under reduced pressure. Het (2.0 L, 10 V) was added to the reactor, then the resulting mixture was stirred at 25°C for 1 h. The mixture was filtered, and the filter cake was collected. After drying, the desired product methyl 4-[(E)- hydroxyiminomethyl]-2-methyl-benzoate (211.30 g, purity 99.18%, yield 97.22%) as an off-white solid was obtained. Step 3: Methyl 2-methyl-4-[rac-(5R)-5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-5- (trifluoromethyl)-4H-isoxazol-3-yl]benzoate

[0160] To a solution of methyl 4-[(E)-hydroxyiminomethyl]-2-methyl-benzoate (10 g, 51.76 mmol) in DMF (100 mL) was added NCS (6.91 g, 51.76 mmol, 4.19 mL) . The reaction mixture was stirred at 50℃ for 1 h, and 1-chloro-2-fluoro-5-(trifluoromethyl)-3-[1-(trifluoromethyl)vinyl]benzene (15.14 g, 51.76 mmol) , DIEA (6.68 g, 51.76 mmol) was added. The resulting mixture was stirred at room temperature for 16 h.

[0161] The reaction was added into water, extracted with ethyl acetate. The combined organic layers were dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The crude product was purified via silica gel column chromatography, eluted with ethyl acetate in petroleum ether from 0% to 80% to afford to get methyl 2-methyl-4-[rac-(5R)-5-[3-chloro-2-fluoro-5- (trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-isoxazol-3-yl]benzoate (12 g, 24.81 mmol, 47.92% yield) as a yellow oil. Step 4: 4-[-5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-isoxazol-3-yl]-2- methyl-benzoic acid

[0162] A solution of methyl 4-[(5S)-5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-5- (trifluoromethyl)-4H-isoxazol-3-yl]-2-methyl-benzoate (6 g, 12.40 mmol) in THF (15 mL) was treated with LiOH (297.05 mg, 12.40 mmol) in H2O (15 mL) for 18h at rt .

[0163] The mixture was neutralized to pH 6 with HCL(1mol / L). The resulting mixture was extracted with EA (3 x 70ml). The combined organic layers were dried over anhydrous sodium sulfate . After filtration, the filtrate was concentrated under reduced pressure to afford 4-[-5-[3-chloro-2-fluoro-5- (trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-isoxazol-3-yl]-2-methyl-benzoic acid (4.89 g, 10.41 mmol, 83.93% yield) as a white solid.Step 5: 4-[5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-isoxazol-3-yl]-N- [2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-benzamide

[0164] To a solution of 4-[5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H- isoxazol-3-yl]-2-methyl-benzoic acid (300 mg, 638.66 μmol) in DMF (5 mL) was added HATU (291.40 mg, 766.39 μmol), DIEA (494.32 mg, 3.83 mmol) and 2-amino-N-(2,2-difluoropropyl)acetamide (145.75 mg, 957.98 μmol). The reaction mixture was stirred at 25 °C for 2 hours. The reaction was monitored with LCMS.

[0165] The resulting mixture was treated with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by Prep-TLC(EA:PE=1:1) to afford the racemic product 4-[5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-isoxazol-3- yl]-N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-benzamide (260 mg, 386.64 μmol, 60.54 % yield, 89.8% purity) as an off-white solid.

[0166] LC-MS (Method H, 0.01-0.85 min 5-95% B, 0.85-1.35 min 95-95% B, 1.35-1.37 min 95-5% B ): Rt = 0.814 min; MS (ESI+): m / z = 604.15 (M+H)+

[0167] 1H NMR (400 MHz, DMSO) δ 8.60 (t, J = 6.0 Hz, 1H), 8.39 – 8.31 (m, 2H), 7.91 (d, J = 6.0, 1H), 7.68 – 7.64 (m, 2H), 7.52 – 7.80 (m, 1H), 4.57 (d, J = 18.5 Hz, 1H), 4.42 (d, J = 18.5 Hz, 1H), 3.90 (d, J = 5.9 Hz, 2H), 3.57 (td, J = 14.0, 6.2 Hz, 2H), 2.40 (s, 3H), 1.58 (t, J = 19.2 Hz, 1H).

[0168] 4-[5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-isoxazol-3-yl]-N- [2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-benzamide (240 mg, 397.44 μmol) was further separated via prep-chiral-HPLC with following conditions:

[0169] Column: CHIRALPAK IE, 2*25 cm, 5 μm; Mobile Phase A: Hex--HPLC, Mobile Phase B: EtOH: DCM=1: 1--HPLC; Flow rate: 20 mL / min; Gradient (B%): isocratic 15% B; Wavelength: 254 / 220 nm; RT1(min): 2.031; RT2(min): 2,619; Sample Solvent: EtOH—HPLC to afford N-[2-(2,2- difluoropropylamino)-2-oxo-ethyl]-2-methyl-4-[rel-(5S)-5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]- 5-(trifluoromethyl)-4H-isoxazol-3-yl]benzamide (55.4 mg, 90.73 μmol, 22.83 % yield, 98.9% purity) as a white solid. (Example 7a, 1st peak) and N-[2-(2,2-difluoropropylamino)-2-oxo-ethyl]-2-methyl-4-[rel- (5R)-5-[3-chloro-2-fluoro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-isoxazol-3-yl]benzamide (55.2 mg, 88.94 μmol, 22.38 % yield, 97.3% purity) as a white solid. (Example 7B, 2nd peak). Example 8

[0170] The activity of the compounds of the invention may be determined by a variety of methods, including in vitro and in vivo methods.Example A: In vitro evaluation of ingestion activity against adult cat fleas

[0171] To prepare the test blood mixture for feeding fleas, the test substance is dissolved in dimethyl sulphoxide and diluted with citrated cattle blood to the desired concentration. To assemble the test set-up, about 20 unfed adult male and female cat fleas (Ctenocephalides felis) are placed into a chamber which is closed at the top and bottom with gauze. A metal cylinder is sealed at one end with parafilm membrane, placed with the sealed base onto the chamber, and filled with the test blood mixture, which can be imbibed by the fleas through the parafilm membrane. The blood cylinder part of the assembled test set-up is contained at about 37°C in an isolated air heated container above the isolating carrier plate holding the flea chambers. The flea chamber part is kept at rt. After 48 h, insecticidal activity against fleas is determined. 100% means that all the fleas have been killed or rendered moribund; 0% means that none of the fleas have been affected at the dose administered. From a dose response curve, the respective EC50 was calculated (4- parameter logistic curve fitting). A substance shows good insecticidal activity against Ctenocephalides felis if the EC50 is below an application rate of 20 ppm.

[0172] In this test for example, the following compounds from the preparation examples showed EC50 < 1 ppm: Examples 1a, 1b, 2a, 2b, 3, 4, 5a, 6a, and 7a.

[0173] In this test for example, the following compounds from the preparation examples showed EC50 < 20 ppm: Examples 1a, 1b, 2a, 2b, 3, 4, 5a, 5b, 6a, 6b, and 7a.

[0174] For the data above, where single isomers were tested, without knowing the absolute configuration of the isomer, the data indicates that the test article is one isomer or another, for example, Example 1a or its enantiomer. Example B: In vitro evaluation of contact activity against adult Brown Dog ticks

[0175] In vitro contact tests with ticks are conducted with adult males and females of Rhipicephalus sanguineus. For the coating of the test vials, the test substance is dissolved and diluted in acetone p.a. to the desired concentration. The solution is then homogeneously applied to the inner walls and base of a glass vial by turning and rocking on an orbital shaker until complete evaporation of the solvent. For example, with 900 ppm solution of test substance an area-based dose of 5 µg / dm² is achieved. After the solvent is completely evaporated, 5 -10 adult ticks are applied to each coated test vial, which is then sealed with a perforated plastic lid and incubated in a horizontal position in the dark at rt and ambient humidity. Acaricidal activity is determined after 48 h. For this, ticks are moved to the base of the test vial by gentle knocking, and test vials are then incubated on a hotplate at 45-50°C for no longer than 5 min. Ticks which remain motionless on the base of the test vial or move uncoordinated without deliberately climbing up to avoid the heat are considered dead or moribund, respectively. An acaricidal activity of 100% means all ticks were dead or moribund. An acaricidal activity of 0% means none of the ticks wasfound dead or moribund. From a dose response curve, the respective EC50was calculated (4-parameter logistic curve fitting). A substance shows good acaricidal activity against Rhipicephalus sanguineus if the EC50is below an application rate of 5 µg / dm².

[0176] In this test for example, the following compounds from the preparation examples showed EC50 < 5 µg / dm2: Examples 1a, 2a, 5a, and 7a.

[0177] For the data above, where single isomers were tested, without knowing the absolute configuration of the isomer, the data indicates that the test article is one isomer or another, for example, Example 1a or its enantiomer. Example C: In vitro evaluation of systemic activity against female engorged Cattle ticks

[0178] To prepare the test compound mixture for injecting ticks, the test substance is dissolved in dimethyl sulphoxide and diluted with the same solvent to the desired concentration.1 µl of the test mixture is injected into each abdomen of 5 engorged adult female cattle ticks (Rhipicephalus (Boophilus) microplus). The ticks are individually transferred into the single compartments of 5x5 replica plates and kept in a climate-controlled chamber (28°C, 85% rel. hum.). Acaricidal activity against cattle ticks is assessed after 7 days by assessment of laid fertile eggs. Eggs which do not appear normal may be stored in a climate-controlled cabinet [28°C, 85% rel h.] until larval hatch after 42 days. An acaricidal activity of 100% means that none of the ticks has laid eggs or laid eggs were infertile; 0% means that all the eggs are fertile. From a dose response curve the respective EC50was calculated (4-parameter logistic curve fitting). A substance shows good systemic acaricidal activity against Rhipicephalus microplus if the EC50is below an application rate of 10 µg / tick.

[0179] In this test for example, the following compounds from the preparation examples showed EC50< 0.5 µg / tick: Examples 1a, 6a, and 7a.

[0180] For the data above, where single isomers were tested, without knowing the absolute configuration of the isomer, the data indicates that the test article is one isomer or another, for example, Example 1a or its enantiomer. Example C: PK determination following administration to beagle dogs

[0181] Behavior of single oral or intravenous dose of the desired compound was assessed in beagle dogs. The animals (n = 3) received the compound by oral gavage (1 mg / kg) or intravenous dose (0.2 mg / kg). Blood samples were collected at (2, 5, 15,) 30 minutes and 1, 2, 4, 8, 12, 24, 48, 72, 96, 168, 336, 504, 672, 1032, 1344, 1680, 2016, 2352, 2688, and 3024 h post dose. A portion of each whole blood sample was processed to plasma. Test article concentrations in plasma and whole blood were determined using LC- MS / MS.

[0182] In this test for example, the following compounds from the preparation examples showed t1 / 2 ~27 d: Examples 1a. Example D: Efficacy determination following administration to beagle dogs

[0183] Behavior of single intravenous administration of 0.4 mg / kg of the desired compound was assessed in beagle dogs (n = 3). On a weekly basis animals were infested with either Amblyomma Americanum, Dermacentor variabilis or Rhipicephalus sanguineus depending on the evaluated efficacy results. Blood samples were collected at 0, 0.25, 4, 8 h post dose and at time of tick infestation and tick removal. (Blood sample preparation as described in example C). Efficacy data were evaluated with the software Phoenix, current version (Phoenix 64; Certara L.P., Princeton, NJ, USA) using the Least-Squares Regression PKPD Model.

[0184] EC90 were evaluated as followed:

[0185] In this test for example, the following compounds from the preparation examples showed EC90 ~ 82 µg / L against Amblyomma Americanum: Examples 1a.

[0186] In this test for example, the following compounds from the preparation examples showed EC90~ 90 µg / L against Dermacentor variabilis: Examples 1a.

[0187] In this test for example, the following compounds from the preparation examples showed EC90 ~ 48 µg / L against Rhipicephalus sanguineus: Examples 1a.

[0188] Many modifications and variations of the embodiments described herein may be made without departing from the scope, as is apparent to those skilled in the art. The specific embodiments described herein are offered by way of example only.

Claims

CLAIMS What is claimed is:

1. A compound of formula (I):or a pharmaceutically acceptable salt thereof, wherein: each of R1, R2, R3, and R4are independently selected from the group consisting of H, halo, CN, and CF3; each of X1and X2is independently F or CH3; and provided each ofe excluded.

2. The compound of claim 1, wherein at least two of R1, R2, R3, and R4are not –H.

3. The compound of claims 1 and 2, wherein at least two of R1, R2, R3, and R4are halo.

4. The compound of any of claims 1 to 3, wherein at least two of R1, R2, R3, and R4are Cl.

5. The compound of any of claims 1 to 3, wherein at least two of R1, R2, R3, and R4are F or Cl.

6. The compound of any of claims 1 to 5, wherein at least one of R1, R2, R3, and R4is CF3.

7. The compound of any of claims 1 to 6, wherein R1and R4are selected from the group consisting of F or H.

8. The compound of any of claims 1 to 7, wherein R2and R3are selected from the group consisting of Cl, CN, or CF3.

9. The compound of any of claims 1 to 8, wherein at least one of X1and X2are CH3.

10. The compound of any of claims 1 to 9, wherein X1and X2are CH3.

11. A compound selected from Table A, or a pharmaceutically acceptable salt thereof.

12. The compound of any of claims 1 to 11, wherein the compound is an (S)-enantiomer.

13. The compound of any one of claims 1 to 12, wherein the compound is in a non-salt form.

14. A pharmaceutical composition comprising a therapeutically effective amount of the compound of any one of claims 1 to 12, or a pharmaceutically acceptable salt thereof, or the compound of claim 13 and one or more pharmaceutically acceptable carriers or vehicles.

15. A method of treating a parasitic disease in a subject comprising administering to the subject the compound of any one of claims 1 to 12, or a pharmaceutically acceptable salt thereof, the compound of claim 13 or the pharmaceutical composition of claim 14.

16. A method of treating or lessening the severity in a subject of a parasitic infection comprising administering to the subject an effective amount of the compound of any one of claims 1 to 12, or a pharmaceutically acceptable salt thereof, the compound of claim 13 or the pharmaceutical composition of claim 14.

17. The method of claim 15, wherein the subject is a non-human animal.

18. Use of the compound of any one of claims 1 to 12, or a pharmaceutically acceptable salt thereof, the compound of claim 13, or the pharmaceutical composition of claim 14, as a medicament.

19. Use of the compound of any one of claims 1 to 12, or a pharmaceutically acceptable salt thereof, the compound of claim 13, or the pharmaceutical composition of claim 14 in the manufacture of a medicament for the treatment of a parasitic disease.

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