Nucleoside compound and application thereof in treating feline infectious peritonitis

Abstract

The invention relates to a nucleoside compound and application of the nucleoside compound in treatment of feline infectious peritonitis. The compound belongs to a GS-441524 analogue. The compound has a very small toxic effect on normal cells of cats, and has an obvious inhibition effect on feline coronavirus. The compound can be used for preparing a feline coronavirus inhibitor, is used for treating feline infectious peritonitis, has the advantages of good curative effect, high safety and the like, and is very good in water solubility and easier to absorb.

Description

[0001] Related Applications

[0002] This application is a divisional application, and its parent application is an invention patent application with an application date of April 21, 2022 and application number CN202280000808.2. Technical Field

[0003] The invention relates to a nucleoside compound and application thereof in treating feline infectious peritonitis. Background Art

[0004] Feline infectious peritonitis (FIP) is a disease caused by infection with feline coronavirus. It is a chronic, progressive, and fatal infectious disease. The disease is commonly seen in two forms clinically. One is the exudative type characterized by peritonitis and a large amount of ascites, which is also called wet infectious peritonitis. The other is dry infectious peritonitis, which is characterized by uveitis such as obvious fibrin clots and retinal hemorrhage in the eyes, without obvious systemic symptom changes.

[0005] At present, the treatment of feline infectious peritonitis mainly uses immunomodulators, immunosuppressants and antiviral drugs for symptomatic treatment. These drugs have significant side effects and cannot reduce the high mortality rate of the disease. Therefore, it is urgent to develop highly effective and safe drugs.

[0006] Feline coronavirus (FCoV) is an RNA virus, a common infectious virus in cats. Cats infected with feline coronavirus have a 5-10% chance of mutating into feline infectious peritonitis (FIP), the main symptoms of which are peritonitis and large amounts of pleural effusion, and the mortality rate of sick cats is extremely high. Currently, GS-441524 is a drug molecule with good effect in treating feline infectious peritonitis (FIP).

[0007] GS-441524 is a 1'-cyano-substituted adenine C-nucleoside ribose analogue, which exhibits strong antiviral activity against a variety of RNA viruses including SARS coronavirus, and has inhibitory effects against a variety of RNA viruses. GS-441524 is phosphorylated into an active triphosphate metabolite (NTP structural analogue) by cellular kinases in cells. In viral RNA synthesis, the active NTP structural analogue acts as a competitor of natural triphosphate nucleosides and competes with natural nucleosides (NTP) to participate in RNA transcription / replication. When GS-441524 molecules are inserted into the transcription / replication product, transcription / replication will terminate prematurely, thereby inhibiting the viral RNA transcription / replication process. It has been found that it exhibits certain inhibitory activity against Ebola, SARS, Junin virus, respiratory syncytial virus, etc. Summary of the invention

[0008] The water solubility of GS441524 molecule is very poor, and its membrane permeability and bioavailability are also relatively limited. Therefore, the novel nucleoside compounds reported in the present invention have strong water solubility, and the compounds have antiviral effects, especially feline coronavirus.

[0009] The present invention aims to provide a compound having a structure as shown in formula (I) or a pharmaceutically acceptable salt thereof:

[0010]

[0011] In formula (I):

[0012] R 1 Selected from C 1-6 Alkyl, C 1-6 Alkenyl, C 1-6 Alkynyl, C 1-6 Haloalkyl, C 3-7 Cycloalkyl, C 3-7 Heterocyclic, hydroxy substituted C 1-6 Alkyl, amino substituted C 1-6 Alkyl, C 1-6 Alkoxy C 1-6 Alkyl, C 1-6 Alkylamino C 1-6 Alkyl, C 3-7 Cycloalkyl C 1-6 Alkyl, C 3-7 Heterocyclyl C 1-6 Alkyl, C 1-6 Alkylamino, hydroxyl substituted C 1-6 Alkylamino, amino substituted C 1-6 Alkylamino, C 1-6 Alkoxy C 1-6 Alkylamino, C 1-6 Alkylamino C 1-6 Alkylamino, C 3-7 Cycloalkyl C 1-6 Alkylamino, C 3-7 Heterocyclyl C 1-6 Alkylamino.

[0013] In another preferred embodiment, wherein in the formula (I), R 1 Selected from -CH 3 、-CH 2 CH 3 、-CH 2 CH 2 CH 3 ,

[0014] -CH(CH 3 ) 2 、-CH 2 CH2 CH 2 CH 3 、

[0015] -CF 3 、-CH 2 CF 3 、

[0016] -CH 2 OH

[0017] -CH 2 NH 2 、-CH 2 OCH 3 、-CH 2 CH 2 OCH 3 、-CH 2 NHCH 3 、-CH 2 N(CH 3 ) 2 、-CH 2 CH 2 NHCH 3 、

[0018] -CH 2 CH 2 N(CH 3 ) 2 、

[0019] -NHCH 3 -NHCH 2 CH 3 -NHCH 2 CH 2 CH 3 、-NHCH(CH 3 ) 2 、-N(CH 3 ) 2 、-N(CH 3 )CH 2 CH 3 、-N(CH 2 CH 3 ) 2 、

[0020] -NHCH 2 CH 2 OH, -NHCH 2 CH 2 NH 2 、-N(CH 2 CH 2 OH) 2 、-NHCH 2 CH 2 OCH 3 、-N(CH 2 CH 2 OCH 3 ) 2 、-NHCH 2 CH 2 NHCH 3 、-NHCH 2 CH 2 N(CH 3 ) 2 、-N(CH 3 )CH 2 CH 2 NHCH 3 、-N(CH 3 )CH 2 CH 2 N(CH 3 ) 2 ,

[0021] In some embodiments of the present invention, the compound of formula (I) or a pharmaceutically acceptable salt thereof is selected from:

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028] One object of the present invention is to provide the compound of the present invention or a pharmaceutically acceptable salt thereof, including each optical isomer, each crystal form, hydrate or solvate.

[0029] Another object of the present invention is to provide a pharmaceutical composition comprising a pharmaceutically acceptable excipient or carrier and a compound of formula (I) of the present invention or a pharmaceutically acceptable salt thereof, including each optical isomer, each crystal form, hydrate or solvate as an active ingredient.

[0030] Another object of the present invention is to provide the use of the compound of the present invention, or each optical isomer thereof, or a pharmaceutically acceptable inorganic or organic salt thereof for preparing a drug for treating a disease caused by feline coronavirus infection, namely feline infectious peritonitis.

[0031] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0033] Figure 1 This is a graph showing the weight changes of a cat before and after two weeks of treatment with the compound of the present invention in water injection;

[0034] Figure 2 This is a graph showing changes in the number of leukocytes in a cat before and after two weeks of treatment with the compound water injection of the present invention;

[0035] Figure 3 This is a graph showing changes in the white blood cell ratio of a cat before and after treatment with the compound of the present invention in two weeks. DETAILED DESCRIPTION

[0036] Certain embodiments of the present invention are now described in detail, examples of which are illustrated by the accompanying structural formulas and chemical formulas. The present invention is intended to cover all substitutions, modifications and equivalent technical solutions, which are all included in the scope of the present invention as defined in the claims. It should be appreciated by those skilled in the art that many methods and materials similar or equivalent to those described herein can be used to practice the present invention. The present invention is in no way limited to the methods and materials described herein. In the event that one or more of the combined documents, patents and similar materials are different from or contradictory to the present application (including but not limited to defined terms, term applications, described technologies, etc.), the present application shall prevail.

[0037] Unless otherwise indicated, the following definitions used herein shall apply. For purposes of the present invention, chemical elements are defined according to the Periodic Table of Chemical Elements, CAS version and Handbook of Chemicals, 75th edition, 1994. In addition, general principles of organic chemistry can be found in "Organic Chemistry", Thomas Sorrell, University Science Books, Sausalito: 1999, and "March's Advanced Organic Chemistry", by Michael B. Smith and Jerry March, John Wiley & Sons, New York: 2007, the entire contents of which are incorporated herein by reference.

[0038] The "pharmaceutically acceptable salts" of the present invention refer to organic salts and inorganic salts of the compounds of the present invention. Pharmaceutically acceptable salts are well known in the art, as described in the literature: SM Berge et al., describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 66: 1-19, 1977. Pharmaceutically acceptable salts formed by non-toxic acids include, but are not limited to: inorganic acid salts formed by reaction with amino groups, such as hydrochlorides, hydrobromides, phosphates, sulfates, perchlorates; organic acid salts, such as acetates, oxalates, maleates, tartrates, citrates, succinates, malonates; or other methods described in books and literature, such as ion exchange methods, to obtain these salts. Other pharmaceutically acceptable salts include adipate, malate, 2-hydroxypropionate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, cyclopentylpropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, picrate, pivalate, propionate, stearate, thiocyanate, p-toluenesulfonate, undecanoate, valerate, and the like. Salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium and N + (C1-4 alkyl) 4The present invention also contemplates quaternary ammonium salts formed by compounds of any N group. Water-soluble or oil-soluble or dispersed products can be obtained by quaternization. Alkali metals or alkaline earth metals that can form salts include sodium, lithium, potassium, calcium, magnesium, etc. Pharmaceutically acceptable salts further include appropriate, non-toxic ammonium, quaternary ammonium salts and amine cations formed by counter-balancing ions, such as halides, hydroxides, carboxylates, sulfates, phosphates, nitrates, C1-S sulfonates and aromatic sulfonates.

[0039] The "solvate" of the present invention refers to an association formed by one or more solvent molecules and the compound of the present invention. Solvents that form solvates include, but are not limited to: water, isopropanol, ethanol, methanol, dimethyl sulfoxide, ethyl acetate, acetic acid and aminoethanol. The term "hydrate" refers to an association formed by the solvent molecule being water.

[0040] In addition, the compounds disclosed in the present invention, including their salts, can also be obtained in the form of their hydrates or in the form of containing their solvents (e.g., ethanol, DMSO, etc.) for their crystallization. The compounds disclosed in the present invention can form solvates inherently or by design with pharmaceutically acceptable solvents (including water); therefore, the present invention is intended to include solvated and unsolvated forms.

[0041] The compounds disclosed herein, including their salts, can be prepared in different forms, including but not limited to, amorphous, pulverized and nano-particle forms. In addition, the compounds of the present invention include crystalline forms and can also be polymorphic. Polymorphs include different lattice arrangements of the same elemental composition of the compound. Polymorphs usually have different X-ray diffraction patterns, infrared spectra, melting points, density, hardness, crystal form, optical and electrical properties, stability and solubility. Different factors such as recrystallization solvents, crystallization rate and storage temperature may cause a single crystal form to dominate.

[0042] As described in the present invention, "pharmaceutically acceptable excipients or carriers" include any solvents, diluents, or other liquid excipients, dispersants or suspending agents, surfactants, isotonic agents, thickeners, emulsifiers, preservatives, solid binders or lubricants, etc., suitable for the specific target dosage form. As described in the following documents: In Remington: The Science and Practice of Pharmacy, 21st edition, 2005, ed. DB Troy, Lippincott Williams & Wilkins, Philadelphia, and Encyclopedia of Pharmaceutical Technology, eds. J. Swarbrick and JC Boylan, 1988-1999, Marcel Dekker, New York, the contents of the documents herein are summarized, indicating that different carriers can be applied to the preparation of pharmaceutically acceptable compositions and their known preparation methods. Except for the scope of any conventional carrier medium incompatible with the compound of the present invention, such as any adverse biological effect produced or interaction with any other component of the pharmaceutically acceptable composition in a harmful manner, their use is also considered within the scope of the present invention.

[0043] Substances that can serve as pharmaceutically acceptable excipients or carriers include, but are not limited to: ion exchangers, aluminum, aluminum oxide, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, electrolytes such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, salts such as sodium chloride, zinc salts, colloidal silicon, magnesium trisilicate, polyvinyl pyrrolidone, polyacrylates, waxes, polyethylene-polyoxypropylene-blocking polymers, lanolin, sugars such as lactose, glucose and sucrose; starches such as corn starch and potato starch; cellulose and its derivatives such as Sodium carboxymethylcellulose, ethylcellulose and cellulose acetate; gum powder; malt; gelatin; talc; excipients such as cocoa butter and suppository wax; oils such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycol compounds such as propylene glycol and polyethylene glycol; esters such as ethyl oleate and ethyl laurate; agar; buffers such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethanol; phosphate buffer solution; and other non-toxic suitable lubricants such as sodium lauryl sulfate and magnesium stearate, colorants, release agents, coatings, sweeteners, flavoring agents and fragrances, preservatives and antioxidants. For convenience, local anesthetics, preservatives, buffers, etc. can be directly dissolved in the carrier.

[0044] The term "alkyl" used in the present invention is a saturated straight or branched monovalent hydrocarbon group of 1 to 20 carbon atoms, wherein the alkyl group may be independently optionally substituted with one or more substituents described in the present invention. In some embodiments, the alkyl group contains 1 to 10 carbon atoms, in other embodiments, the alkyl group contains 1 to 8 carbon atoms, in other embodiments, the alkyl group contains 1 to 6 carbon atoms, in other embodiments, the alkyl group contains 1 to 4 carbon atoms, and in other embodiments, the alkyl group contains 1 to 3 carbon atoms. Further examples of alkyl groups include, but are not limited to, methyl (Me, -CH 3 ), ethyl (Et, -CH 2 CH 3 ), n-propyl (n-Pr, -CH 2 CH 2 CH 3 ), isopropyl (i-Pr, -CH(CH 3 ) 2 ), n-butyl (-Bu, -CH 2 CH 2 CH 2 CH 3 ), 2-methylpropyl or isobutyl (i-Bu, -CH 2 CH(CH 3 ) 2 ), 1-methylpropyl or sec-butyl (s-Bu, -CH(CH 3 )CH 2 CH 3 ), tert-butyl (t-Bu, -C(CH 3 ) 3 ), n-pentyl (-CH 2 CH 2 CH 2 CH 2 CH 3 ), 2-pentyl (-CH(CH 3 )CH 2 CH 2 CH 3 ), 3-pentyl (-CH(CH 2 CH 3 ) 2 ), 2-methyl-2-butyl (-C(CH 3 ) 2 CH 2 CH 3 ), 3-methyl-2-butyl (-CH(CH 3 )CH(CH 3 ) 2 ), 3-methyl-1-butyl (-CH 2 CH 2CH(CH 3 ) 2 ), 2-methyl-1-butyl (-CH 2 CH(CH 3 )CH 2 CH 3 ), n-hexyl (-CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 ), 2-hexyl (-CH(CH 3 )CH 2 CH 2 CH 2 CH 3 ), 3-hexyl (-CH(CH 2 CH 3 )(CH 2 CH 2 CH 3 )), 2-methyl-2-pentyl (-C(CH 3 ) 2 CH 2 CH 2 CH 3 ), 3-methyl-2-pentyl (-CH(CH 3 )CH(CH 3 )CH 2 CH 3 ), 4-methyl-2-pentyl (-CH(CH 3 )CH 2 CH(CH 3 ) 2 ), 3-methyl-3-pentyl (-C(CH 3 )(CH 2 CH 3 ) 2 ), 2-methyl-3-pentyl (-CH(CH 2 CH 3 )CH(CH 3 ) 2 ), 2,3-dimethyl-2-butyl (-C(CH 3 ) 2 CH(CH 3 ) 2 ), 3,3-dimethyl-2-butyl (-CH(CH 3 )C(CH 3 ) 3 ), n-heptyl, n-octyl, etc. The term "alkyl" and its prefix "alkane" as used herein include both straight and branched saturated carbon chains.

[0045] The term "alkenyl" used in the present invention refers to an unsaturated aliphatic hydrocarbon group containing a carbon-carbon double bond, including straight and branched groups of 1 to 6 carbon atoms. Preferably, the lower alkenyl group contains 1 to 4 carbon atoms, such as vinyl, 1-propenyl, 1-butenyl or 2-methylpropenyl.

[0046] The term "alkynyl" as used in the present invention refers to a linear or branched monovalent hydrocarbon group of 2 to 12 carbon atoms, wherein at least one position is unsaturated, i.e., one CC is a sp triple bond, wherein the alkynyl group may be independently and optionally substituted by one or more substituents described in the present invention, specific examples include, but are not limited to, ethynyl Propargyl etc.

[0047] The term "alkoxy" as used herein refers to an alkyl group, as defined herein, attached to the main carbon chain via an oxygen atom. Unless otherwise specified, the alkoxy group contains 1-12 carbon atoms. In one embodiment, the alkoxy group contains 1-6 carbon atoms; in another embodiment, the alkoxy group contains 1-4 carbon atoms; in yet another embodiment, the alkoxy group contains 1-3 carbon atoms. Such examples include, but are not limited to, methoxy, ethoxy, propoxy, and the like.

[0048] The term "haloalkyl" or "haloalkoxy" as used herein refers to an alkyl or alkoxy group which may be substituted by one or more halogen atoms which may be the same or different. The alkyl and alkoxy groups have the meanings as described herein, and examples thereof include, but are not limited to, 1,1,1-trifluoro-2-methylprop-2-yl (-C(CH 3 ) 2 CF 3 ), 1,1-difluoro-2-methylpropan-2-yl (-C(CH 3 ) 2 CHF 2 ), 1-fluoro-2-methylpropan-2-yl (-C(CH 3 ) 2 CH 2 F), difluoromethyl (-CHF 2 ), trifluoromethyl (-CF 3 ), trifluoromethoxy (-OCF 3 )、2,2,2-trifluoroethoxy(-OCH 2 CF 3 )、2,2,3,3-tetrafluoropropoxy(-OCH 2 CF 2 CHF 2 ),wait.

[0049] As used herein, the terms "carbocyclyl" or "cycloaliphatic", "carbocycle", "cycloalkyl" refer to monovalent or polyvalent, non-aromatic, saturated or partially unsaturated rings, and do not contain heteroatoms, including monocyclic rings of 3-12 carbon atoms or bicyclic or tricyclic rings of 7-12 carbon atoms. Bicyclic rings with 7-12 atoms may be bicyclic [4,5], [5,5], [5,6] or [6,6] systems, while bicyclic rings with 9 or 10 atoms may be bicyclic [5,6] or [6,6] systems. Depending on the structure, "carbocyclyl" or "cycloaliphatic", "carbocycle", "cycloalkyl" may be a monovalent group or a divalent group, i.e., in certain embodiments of the present invention, it may be used instead of or as a carbocyclylene or cycloalkylene group. Suitable cycloaliphatic groups include, but are not limited to, cycloalkyl, cycloalkenyl and cycloalkynyl groups. Examples of cyclic aliphatic groups further include, but are in no way limited to, cyclopropyl, cyclobutyl, cyclopentyl, 1-cyclopentyl-1-enyl, 1-cyclopentyl-2-enyl, 1-cyclopentyl-3-enyl, cyclohexyl, 1-cyclohexyl-1-enyl, 1-cyclohexyl-2-enyl, 1-cyclohexyl-3-enyl, cyclohexadienyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, adamantyl, etc. And the "carbocyclyl" or "cyclic aliphatic", "carbocycle", "cycloalkyl" can be substituted or unsubstituted, wherein the substituent can be, but is not limited to, oxo (=O), fluorine, chlorine, bromine, iodine, hydroxyl, amino, -C(=O)-NH 2 , carboxyl, -S(=O) t OH, -OS(=O) t -H, -S(=O) t NH 2 , triazolyl, tetrazolyl, -(CR 3b R 3c ) n -NH 2 , alkyl, alkyl-S(=O) t -, haloalkyl, hydroxyalkyl, alkoxy, alkylamino, alkylthio, haloalkoxy, amino, aryl, heteroaryl, alkenyl, alkynyl, heterocyclyl, mercapto, nitro, aryloxy, hydroxyalkoxy, alkanoyl, benzyl, cyclopropyl, phenyl, alkyl-C(=O)-, alkyl-C(=O)-NH-, formamido or alkoxyalkyl, etc.

[0050] The term "heterocyclyl" as used herein refers to a saturated or partially unsaturated ring system radical containing one or more heteroatoms (O, S or N), wherein the nitrogen and sulfur atoms are optionally oxidized and the nitrogen atom is optionally quaternized as ring atoms. Unless otherwise indicated, the ring system of a "heterocycloalkyl" may be a monocyclic, bicyclic, spirocyclic or polycyclic ring system. A "heterocycloalkyl" may be attached to the rest of the molecule via one or more ring carbons or heteroatoms. Examples of "heterocycloalkyl" include, but are not limited to, pyrrolidine, piperidine, N-methylpiperidine, tetrahydroimidazole, pyrazolidine, butyrolactam, valerolactam, imidazolinone, hydantoin, dioxolane, phthalimide, piperidine, pyrimidine-2,4(1H,3H)-dione, 1,4-dioxane, morpholine, thiomorpholine, thiomorpholine-S-oxide, thiomorpholine-S,S-oxide, piperazine, pyran, pyridone, 3-pyrroline, thiopyran, pyrone, tetrahydrofuran, tetrahydrothiophene, quinuclidine, 2-azaspiro[3.3]heptane, and the like.

[0051] The term "alkylamino" as used herein refers to "N-alkylamino" wherein the amino groups are independently substituted by one or two alkyl groups, wherein the alkyl groups have the meanings as described herein. In some embodiments, the alkylamino group is C 1-6 Alkyl is attached to the nitrogen atom of the lower alkylamino group. In some other embodiments, the alkylamino is C 1-3 Examples include, but are not limited to, N-methylamino, N-ethylamino, and the like.

[0052] Synthesis of compounds:

[0053] The following specifically describes the preparation methods of the compounds of formula (I) of the present invention, but these specific methods do not constitute any limitation to the present invention.

[0054] The compounds of formula (I) described above can be synthesized using standard synthetic techniques or known techniques in combination with the methods described herein. In addition, the solvents, temperatures and other reaction conditions mentioned herein may vary. The starting materials used in the synthesis of the compounds can be synthesized or obtained from commercial sources, such as, but not limited to, Aldrich Chemical Co.

[0055] (Milwaukee, Wis.) or Sigma Chemical Co. (St. Louis, Mo.) The general methods for the preparation of compounds can be modified by using appropriate reagents and conditions to introduce various groups into the formulae provided herein.

[0056] On the one hand, the compounds described herein are based on methods known in the art. However, the conditions of the method, such as reactants, solvents, bases, the amount of compounds used, reaction temperature, reaction time, etc. are not limited to the following explanation. The compounds of the present invention can also be conveniently prepared by optionally combining various synthetic methods described in this specification or known in the art, and such combinations can be easily performed by technicians in the field to which the present invention belongs. On the one hand, the present invention also provides a method for preparing the compound shown in the general formula (I), which is prepared using the following general reaction flow:

[0057]

[0058] Where R 1 and R 2 The definition of is as mentioned above.

[0059] Using compound A as the starting material, a compound of general formula (I) is obtained through a nucleophilic substitution reaction.

[0060] The above features mentioned in the present invention or the features mentioned in the embodiments can be combined in any way. All the features disclosed in the specification of this case can be used in any combination form, and each feature disclosed in the specification can be replaced by any alternative feature that can provide the same, equal or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equal or similar features.

[0061] In the following description, each specific aspect, characteristic and advantage of the above-mentioned compounds, methods and pharmaceutical compositions will be described in detail to make the content of the present invention become very clear. It should be understood that the following detailed description and examples describe specific embodiments and are for reference only. After reading the description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent situations also fall within the scope defined by the application.

[0062] In all embodiments, 1 H-NMR was recorded on a Vian Mercury 400 nuclear magnetic resonance instrument, and chemical shifts were expressed in δ (ppm). The silica gel used for separation was 200-300 mesh unless otherwise specified, and the ratios of the eluents were all by volume.

[0063] The present invention uses the following abbreviations: room temperature (RT, rt); aqueous solution (aq.); petroleum ether (PE); ethyl acetate (EA); dichloromethane (DCM); methanol (MeOH); methyl tert-butyl ether (MTBE); ethanol (EtOH); trifluoroacetic acid (TFA); equivalent (eq); gram / milligram (g / mg); mole / millimole (mol / mmol); liter / milliliter (L / mL); minute (min(s)); hour (h, hr, hrs); nitrogen (N 2); nuclear magnetic resonance (NMR); liquid chromatography-mass spectrometry (LC-MS); thin layer chromatography (TLC); preparative liquid chromatography (pre-HPLC).

[0064] Example 1: Preparation of Compound 32:

[0065]

[0066] Step 1: Add 1.32 g of tert-butoxyacetic acid and 0.84 g of sodium bicarbonate to 30 mL of DMSO and stir at room temperature for 20 min until dissolved. Add 12.0 g of raw material A at room temperature and heat to 65°C to react overnight. The raw material disappears and the product is generated. Stop the reaction, extract with EA / water until there is almost no product in the water layer, wash the organic phase with saturated brine, dry and concentrate it, and elute with DCM / MeOH=30 / 1 to obtain 1.1 g of white solid B1.

[0067] 1 HNMR (400 MHz, DMSO-d 6 )δ8.05–7.86(m,3H),6.92(d,J=4.4Hz,1H),6.82(d,J=4.4Hz,1H),6.36(d,J=6.0Hz,1H),5.42(d,J=5.8Hz,1H) ,4.68(t,J=5.4Hz,1H),4.38(d,J=9.8Hz,1H),4.28–4.14(m,2H),4.00(s,2H),3.96–3.89(m,1H),1.12(s,9H).

[0068] Step 2: Dissolve 500 mg of the raw material compound B1 in 10 mL of DCM, add 3 mL of TFA dropwise under an ice bath, and react at room temperature for 1 hour. LCMS shows that the reaction is complete. The product is generated. Stop the reaction, concentrate at low temperature to remove the solvent, and distill twice with DCM to obtain a colorless oil. Slurry with 10 mL of MTBE to obtain a white solid, and then slurry with 5 mL of DCM twice. Concentrate and drain to obtain a white solid of 600 mg of the trifluoroacetate salt of compound 32.

[0069] The synthesis of similar compounds can give the compounds listed in Table 1:

[0070] Table 1. Compounds 1-106:

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] Representative compounds 1 H-NMR data

[0080]

[0081] 1 H NMR (500 MHz, DMSO-d 6 )δ7.93(s,3H),6.91(d,J=4.5Hz,1H),6.81(d,J=4.5Hz,1H),6.33(d,J=6.0Hz,1H),5.39(d,J=5.8Hz,1H),4.71–4.68(m,1H),4.31 (dd,J=12.0,2.9Hz,1H),4.26–4.21(m,1H),4.17(dd,J=12.1,5.2Hz,1H),3.98–3.93(m,1H),2.56–2.52(m,1H),1.08–1.03(m,6H).

[0082]

[0083] 1 H NMR (500 MHz, DMSO-d 6 )δ8.05–7.80(m,3H),6.93(d,J=4.6 Hz,1H),6.82(d,J=4.5 Hz,1H),6.34(d,J=6.1 Hz,1H),5.42(d,J=5.9 Hz,1H),4.74–4.68(m,1H),4.48–4.41(m,1H),4.33–4.23(m,2H),4.01–3.93(m,1H),3.80–3.67(m,2H).

[0084]

[0085] 1 H NMR (500 MHz, DMSO-d 6)δ8.02–7.78(m,3H),6.91(d,J=4.6 Hz,1H),6.79(d,J=4.5 Hz,1H),6.34(d,J=6.0 Hz,1H),5.38(d,J=6.0 Hz,1H),4.67(t,J=5.4 Hz,1H),4.38–4.29(m,1H),4.26–4.12(m,2H),3.98–3.88(m,1H),3.21–3.09(m,1H),2.20–2.06(m,4H),1.98–1.86(m,1H),1.84–1.73(m,1H).

[0086]

[0087] 1 H NMR(500 MHz,DMSO-d 6 )δ8.04–7.78(m,3H),6.92(d,J=4.5 Hz,1H),6.81(d,J=4.6 Hz,1H),6.34(d,J=6.0 Hz,1H),5.39(d,J=5.9 Hz,1H),4.74–4.65(m,1H),4.36–4.28(m,1H),4.27–4.21(m,1H),4.20–4.14(m,1H),4.00–3.91(m,1H),2.76–2.66(m,1H),1.85–1.71(m,2H),1.69–1.45(m,6H).

[0088]

[0089] 1 H NMR(500MHz,DMSO-d 6 )δ8.06–7.79(m,3H),6.93(d,J=4.5Hz,1H),6.82(d,J=4.5Hz,1H),6.34(d,J=6.0Hz,1H),5.38(d,J=5.9Hz,1H),4.74–4.68(m,1H),4.31(dd,J=12.2,2.9Hz,1H),4.26–4.21(m,1H),4.15(dd,J=12.2,5.0Hz,1H),4.00–3.94(m,1H),2.30–2.22(m,1H),1.81–1.54(m,5H),1.34–1.11(m,5H).

[0090]

[0091] 1HNMR (400 MHz, DMSO-d 6 )δ8.05–7.77(m,3H),6.91(d,J=3.4Hz,1H),6.81(d,J=3.4Hz,1H),6.29(d,J=5.9Hz,1H),5. 44–5.31(m,2H),4.76–4.65(m,1H),4.44–4.33(m,1H),4.30–4.16(m,2H),4.06–3.88(m,3H).

[0092]

[0093] 1 H NMR (500 MHz, DMSO-d 6 )δ8.02–7.78(s,3H),6.90(d,J=4.5Hz,1H),6.78(d,J=4.5Hz,1H),6.30–6.24(m,1H),5.39–5.31(m,1H),4.73–4.66(m,1H),4.36–4. 18(m,2H),4.16–4.07(m,1H),4.00–3.94(m,1H),3.28–3.17(m,2H),2.85–2.74(m,3H),2.35–2.24(m,2H),2.14(s,3H),2.06(s,3H).

[0094] Example 2: Solubility Test

[0095] Experimental method: Determined by referring to high performance liquid chromatography (Chinese Pharmacopoeia 2020 Edition, Part IV, General Rules 0512).

[0096] a. Take about 1-2 mg of the compound, place it in a 10 ml volumetric flask, add 1 ml of water, shake vigorously for 30 seconds every 5 minutes, observe for 30 minutes, if the sample is not completely dissolved, filter it through a 0.45 μm filter membrane, and take the filtrate as the test solution.

[0097] b. Take an appropriate amount of reference substance, dissolve it in solvent (DMSO: methanol = 10:90) and quantitatively dilute it to make a solution containing 0.1 mg per 1 ml as the reference substance solution.

[0098] c. Accurately measure 20 μl of each reference substance and test substance solution, inject them into the liquid chromatograph respectively, and calculate the peak area according to the external standard method. The obtained data is shown in Table 2. Calculation formula: Where: A 供 : Main peak area of ​​the test solution; A 对 : Main peak area of ​​reference solution; W 对 : Reference substance weight, mg; V 对: dilution volume of reference substance solution, ml; S: content of reference substance, %.

[0099] d. Chromatographic conditions: Octadecylsilane bonded silica gel was used as filler (Welch Ultimate XB-C18, 4.6×150 mm, 5 μm column is suitable); 0.05% H 3 PO 4 Solution (take H 3 PO 4 0.5ml, diluted with water to 1000ml) as mobile phase A, acetonitrile as mobile phase B, linear gradient elution according to the following table; column temperature 30℃, detection wavelength 254nm.

[0100]

[0101] Table 2. Solubility of the compounds of the present invention in water

[0102] Note: “+” represents 1≤solubility of the compound of the present invention / solubility of GS-441524<10; “++” represents 10≤solubility of the compound of the present invention / solubility of GS-441524<100; “+++” represents solubility of the compound of the present invention / solubility of GS-441524≥100.

[0103] Compared with GS-441524, the compound of the present invention has higher solubility in water, so the compound of the present invention is more easily absorbed by the organism.

[0104] serial number Solubility serial number Solubility serial number Solubility serial number Solubility 1 ++ 2 ++ 4 ++ 6 ++ 11 ++ 13 ++ 15 ++ 26 ++ 30 +++ 32 ++ 33 +++ 35 ++ 39 +++ 40 ++ 55 +++ 61 ++ 79 +++ 81 ++ 85 +++ 88 ++ 97 +++ GS-441524 0.05mg / mL

[0105] Example 3: Efficacy experiment of compounds 1, 32, and 85 on feline infectious peritonitis

[0106] Experimental methods:

[0107] Dissolve 15 mg of compound 1, 32, and 85 in 5 mL of solution (water: propylene glycol: PEG = 2:1:1) to prepare injection solution, and inject it. The injection solution can be stored at room temperature. Use a 2 mL disposable veterinary syringe to draw the corresponding volume of injection solution and expel the air upward. When injecting, choose a site with softer skin, loose subcutaneous tissue and fewer blood vessels, such as the neck or inner thigh for subcutaneous injection. The dosage is 2 mg / kg body weight once a day. Blood is collected every three days and blood routine and corresponding biochemical indicators are measured. The experiment ends when the cat's biochemical indicators return to normal. The indicator data measured in the experiment are body weight data, white blood cell data and white blood cell ratio data. The experimental subjects of each compound are 15 cats diagnosed with feline infectious peritonitis.

[0108] Figure 1The figure shows the weight changes of 15 cats in each group suffering from feline infectious peritonitis before and after two weeks of treatment with aqueous injections prepared with compounds 1, 32 and 85 respectively (vertical axis unit: kilograms, white columns represent before treatment, black columns represent after treatment, the first and second bars of each group of data are compound 1, the third and fourth bars are compound 32, and the fifth and sixth bars are compound 85).

[0109] from Figure 1 In the figure, we can see the changes in the body weight of cats treated with aqueous injections of compounds 1, 32 and 85 two weeks before and after treatment. The weight of the cats after treatment was greater than that before treatment.

[0110] Figure 2 The graph shows the changes in the number of leukocytes in 15 experimental cats before and after two weeks of treatment with water injections of compounds 1, 32 and 85 (vertical axis unit: 1×10 9 / L, white columns represent before treatment, black columns represent after treatment, the first and second columns of each group of data are compound 1, the third and fourth columns are compound 32, and the fifth and sixth columns are compound 85).

[0111] from Figure 2 It can be seen that the number of white blood cells in cats treated with aqueous injections of compounds 1, 32 and 85 respectively increased significantly.

[0112] Figure 3 The figure shows the changes in the white-to-ball ratio of 15 experimental cats two weeks before and after the treatment with water injections of compounds 1, 32, and 85, respectively (the white columns represent before treatment, the black columns represent after treatment, and the first and second columns of each group of data are compound 1, the third and fourth columns are compound 32, and the fifth and sixth columns are compound 85).

[0113] from Figure 3 It can be seen that the white-globulin ratios of 15 cats suffering from feline infectious peritonitis corresponding to compounds 1, 32, and 85 respectively reached normal values ​​after being treated with water injections prepared with compounds 1, 32, and 85 for two weeks.

[0114] In this experiment, 15 cats in each of the three groups with feline infectious peritonitis were cured and there was no recurrence. The series of compounds reported in this patent have very good water solubility, which is very different from the traditional GS441524 oily injection. It has higher absorption efficiency, is easier to disperse in the body, and the dosage is significantly lower than the traditional injection.

[0115] Example 4: In vitro anti-feline infectious peritonitis virus (FIPV) activity of the compounds

[0116] Experimental methods:

[0117] CRFK cells with good growth status were taken and inoculated on 96-well plates. When the cells grew to 80%-90% confluence, 0.1MOI feline coronavirus (FIPV) and different concentrations of test compounds (0.3125μM, 0.625μM, 1.25μM, 2.5μM, 5μM, 10μM, 20μM and 40μM) were added to each well. Cell control and virus control were set at the same time. All wells contained 1% DMSO. After incubation at 37°C for 72h, the cells were treated with CellTiter-Glo luminescent cell viability detection reagent (Promega, Madison, WI, USA), and the half effective concentration (EC) of the compound for virus inhibition was calculated using GraphPad prism 7 software. 50 )value.

[0118] Table 3, In vitro inhibitory activity of the compounds of the present invention against feline infectious peritonitis virus (FIPV)

[0119] Compound 4 14 16 18 32 <![CDATA[EC 50 (μM)]]> 0.65 2.95 0.81 0.35 6.21

[0120] As can be seen from Table 3, compounds 4, 14, 16, 18 and 32 of the present invention can inhibit the replication of feline infectious peritonitis virus (FIPV) in vitro, among which compounds 4, 16 and 18 have significant antiviral activity, EC 50 They are 0.65 μM, 0.81 μM and 0.35 μM respectively.

Claims

1. A compound having a structure as shown in formula (I) or a pharmaceutically acceptable salt thereof: in: R 1 Selected from C 1-6 Alkyl, C 1-6 Alkenyl, C 1-6 Alkynyl, C 1-6 Haloalkyl, C 3-7 Cycloalkyl, C 3-7 Heterocyclic, hydroxy substituted C 1-6 Alkyl, amino substituted C 1-6 Alkyl, C 1-6 Alkoxy C 1-6 Alkyl, C 1-6 Alkylamino C 1-6 Alkyl, C 3-7 Cycloalkyl C 1-6 Alkyl, C 3-7 Heterocyclyl C 1-6 Alkyl, C 1-6 Alkylamino, hydroxyl substituted C 1-6 Alkylamino, amino substituted C 1-6 Alkylamino, C 1-6 Alkoxy C 1-6 Alkylamino, C 1-6 Alkylamino C 1-6 Alkylamino, C 3-7 Cycloalkyl C 1-6 Alkylamino, C 3-7 Heterocyclyl C 1-6 Alkylamino.

2. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, characterized in that: The R 1 Selected from -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)2, -CH2CH2CH2CH3, -CF3, -CH2CF3, -CH2OH, -CH2NH2, -CH2OCH3, -CH2CH2OCH3, -CH2NHCH3, -CH2N(CH3)2, -CH2CH2NHCH3, -CH2CH2N(CH3)2, -NHCH3、-NHCH2CH3、-NHCH2CH2CH3、-NHCH(CH3)2、-N(CH3)2、-N(CH3)CH2CH3、-N(CH2CH3)2、 -NHCH2CH2OH、-NHCH2CH2NH2、-N(CH2CH2OH)2、-NHCH2CH2OCH3、-N(CH2CH2OCH3)2、-NHCH2CH2NHCH3、-NHCH2CH2N(CH3)2、、-N(CH3)CH2CH2NHCH3、-N(CH3)CH2CH2N(CH3)2、 3. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, characterized in that: The compound has one of the following structures:

4. A pharmaceutical composition, characterized in that A pharmaceutical composition comprising a pharmaceutically acceptable excipient or carrier and a compound according to any one of claims 1 to 3 or a pharmaceutically acceptable salt thereof as an active ingredient, wherein the active ingredient includes each optical isomer, each crystal form, hydrate or solvate thereof.

5. as any one compound among claim 1-3 or its pharmaceutically acceptable salt, purposes in treating the disease caused by feline coronavirus infection, or purposes in the medicine for preparing the disease caused by treating feline coronavirus infection.

6. The use of a pharmaceutical composition as claimed in claim 4 in a medicine for treating a disease caused by a feline coronavirus infection, or in a medicine for preparing a disease caused by a feline coronavirus infection.

7. The use according to claim 5 or 6, characterized in that The disease caused by the feline coronavirus infection is feline infectious peritonitis.

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