Pentacyclic triterpenoids and pharmaceutically acceptable salts thereof, and preparation method and application of pentacyclic triterpenoids and pharmaceutically acceptable salts thereof

Abstract

The invention relates to the technical field of medicinal chemistry, in particular to a pentacyclic triterpenoid compound and pharmaceutically acceptable salt thereof, and a preparation method and application of the pentacyclic triterpenoid compound. The pentacyclic triterpenoid has 3CL protease inhibitory activity, and the structure of the pentacyclic triterpenoid is selected from a formula (I) or a formula (II). R1 is selected from hydroxyl or # imgabs0 # R2, R3 and R4 are respectively and independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C10 aryl, substituted or unsubstituted C3-C10 heteroaryl, or C1-C4 alkylene or olefinic bond and a proper combination of the above groups, and the pentacyclic triterpenoids do not include compounds in which R1 is selected from hydroxyl and R2 is selected from hydrogen. # imgabs1 #

Description

Technical Field

[0001] The present application relates to the technical field of pharmaceutical chemistry, and in particular to a pentacyclic triterpenoid compound and a pharmaceutically acceptable salt thereof, and a preparation method and application thereof. Background Art

[0002] The current treatment of infectious diseases caused by the SARS-CoV-2 virus mainly focuses on symptomatic treatment. There is an urgent need to develop a new drug that can inhibit viral replication and thus play a preventive and therapeutic role.

[0003] Among the many targets against SARS-CoV-2 virus, the main protease / 3CL protease (Mpro / 3CL pro ) plays an extremely critical role in the replication and transcription of progeny viruses and is an enzyme necessary for coronavirus replication, so it has attracted much attention from researchers. pro 3CL has high structural similarity and conservation in various coronaviruses including SARS-CoV-2 virus variants. pro It is considered to be one of the most attractive targets for the development of coronavirus targeted drugs. Therefore, it is necessary to develop a new 3CL protease inhibitor for the prevention and treatment of related target diseases. Summary of the invention

[0004] Based on this, the purpose of the present application includes providing a pentacyclic triterpenoid compound and a pharmaceutically acceptable salt thereof, a preparation method and application thereof, wherein the pentacyclic triterpenoid compound and a pharmaceutically acceptable salt thereof have the effects of inhibiting 3CL pro It can be used to prepare drugs for preventing and / or treating coronavirus infection, and drugs for preventing and / or treating small RNA virus infection.

[0005] A pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof, wherein the pentacyclic triterpenoid compound is selected from the compound of formula (I) or the compound of formula (II);

[0006]

[0007] R 1 Selected from hydroxyl or

[0008] R 2 , R 3 and R 4 are independently selected from: hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C 10 Aryl, substituted or unsubstituted C3~C 10 Heteroaryl, or a suitable combination of C1-C4 alkylene or olefinic bond with the aforementioned groups.

[0009] The pentacyclic triterpenoid compounds do not include R 1 is selected from hydroxyl and R 2 A compound I-1 selected from hydrogen;

[0010]

[0011] The preparation method of the compound of formula (I) comprises the following steps:

[0012]

[0013] Take a compound of formula (I-1) and a compound R 11 -X1 undergoes esterification reaction to obtain a compound of formula (I-2),

[0014] The compound of formula (I-2) and the compound Esterification reaction is carried out to obtain a compound of formula (I-3), or

[0015] Take the compound of formula (I-1) and the compound Carry out esterification reaction to obtain a compound of formula (I-4);

[0016] Take a compound of formula (I-4) and a compound R 14 -X2 undergoes esterification reaction to obtain a compound of formula (I-5);

[0017] in,

[0018] R 12 and R 13 As R 1 Definition of;

[0019] R 11 and R 14 As R 2 Definition of;

[0020] X1 and X2 are independently selected from halogen;

[0021] N1 and N2 are each independently selected from a leaving group.

[0022] The preparation method of the compound of formula (II) comprises the following steps:

[0023]

[0024] Take a compound of formula (I-1) and a compound R 15 -X3 undergoes esterification reaction to obtain a compound of formula (I-6),

[0025] Taking the compound of formula (I-6) and subjecting it to oxidation reaction, oxidizing the hydroxyl group therein to keto group, to prepare the compound of formula (II-1);

[0026] Among them, R 15 The definition of R 3 ;

[0027] X3 is selected from halogen.

[0028] A pharmaceutical composition comprising:

[0029] 1) the pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof as described in any of the above technical solutions; and

[0030] 2) Pharmaceutically acceptable carrier.

[0031] Use of the pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof described in any of the above technical solutions in the preparation of a drug;

[0032] The drug is selected from: 1) a drug for preventing and / or treating coronavirus infection, and 2) a drug for preventing and / or treating small RNA virus infection. DETAILED DESCRIPTION

[0033] The present application will be further described below in conjunction with the embodiments and examples. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. In addition, it should be understood that after reading the content taught in the present application, those skilled in the art may make various changes or modifications to the present application, and these equivalent forms also fall within the protection scope of the claims attached to the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0035] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0036] The terms "and / or", "or / and", and "and / or" used in this article include any one of two or more related listed items, and also include any and all combinations of related listed items, and the arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0037] Herein, "preferred", "preferable", "better", etc. are only used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of this application.

[0038] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0039] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0040] In the present application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0041] In the present application, weight may be μg, mg, g, kg or other mass units known in the chemical industry.

[0042] The term "alkyl" in the present application refers to a monovalent residue formed by the loss of a hydrogen atom from a saturated hydrocarbon containing a primary (normal) carbon atom, or a secondary carbon atom, or a tertiary carbon atom, or a quaternary carbon atom, or a combination thereof. A phrase containing this term, for example, "C1-C6 alkyl" refers to an alkyl group containing 1 to 6 carbon atoms, and each occurrence can be independently C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl or C6 alkyl. Suitable examples include, but are not limited to: methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -C H(CH3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH2CH3)2), 2-methyl-2-butyl (-C(CH3)2CH2CH3), 3-methyl-2-butyl (-CH(CH3)CH(CH3)2), 3-methyl -1-butyl (-CH2CH2CH(CH3)2), 2-methyl-1-butyl (-CH2CH(CH3)CH2CH3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 2-hexyl (-CH(CH3)CH2CH2CH2CH3), 3-hexyl (-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl (-C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl ( -CH(CH3)CH(CH3)CH2CH3), 4-methyl-2-pentyl (-CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (-C(CH3)(CH2CH3)2), 2-methyl-3-pentyl (-CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (-C(CH3)2CH(CH3)2), 3,3-dimethyl-2-butyl and (-CH(CH3)C(CH3)3.

[0043] The term "alkylene" in this application refers to a hydrocarbon group having two monovalent group centers derived from an alkyl group by removing two hydrogen atoms, which may be a saturated branched alkyl group or a saturated straight-chain alkyl group. For example, "C1-C6 alkylene" means that the alkyl portion contains 1 to 6 carbon atoms, and each occurrence may be independently C1 alkylene, C2 alkylene, C3 alkylene, C4 alkylene, C5 alkylene or C6 alkylene. Suitable examples include, but are not limited to, methylene (-CH2-), 1,1-ethyl (-CH(CH3)-), 1,2-ethyl (-CH2CH2-), 1,1-propyl (-CH(CH2CH3)-), 1,2-propyl (-CH2CH(CH3)-), 1,3-propyl (-CH2CH2CH2-) and 1,4-butyl (-CH2CH2CH2CH2-).

[0044] The term "cycloalkyl" in this application refers to a non-aromatic hydrocarbon containing ring carbon atoms, which can be a monocyclic alkyl, a spirocyclic alkyl, or a bridged cycloalkyl. Phrases containing this term, for example, "C3-C8 cycloalkyl" refers to a cycloalkyl containing 3 to 8 carbon atoms, each occurrence of which can be independently of each other C3 cycloalkyl, C4 cycloalkyl, C5 cycloalkyl, C6 cycloalkyl, C7 cycloalkyl or C8 cycloalkyl. Suitable examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl. In addition, "cycloalkyl" may also contain one or more double bonds, and representative examples of cycloalkyl containing double bonds include cyclopentenyl, cyclohexenyl, cyclohexadienyl and cyclobutadienyl.

[0045] The term "aryl" in this application refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing a hydrogen atom. It can be a monocyclic aromatic group, a condensed aromatic group, or a polycyclic aromatic group. For polycyclic rings, at least one is an aromatic ring system. For example, "C6-C 10 "Aryl" refers to an aromatic group containing 6 to 10 carbon atoms, each occurrence of which can be independently C6 aryl, C7 aryl, C8 aryl, C9 aryl or C 10 Suitable examples include, but are not limited to, benzene, biphenyl, naphthalene, anthracene, phenanthrene, perylene, triphenylene, and derivatives thereof.

[0046] The term "heteroaryl" in the present application means that at least one carbon atom on the basis of an aryl or cyclopentadienyl group is replaced by a non-carbon atom, and the non-carbon atom may be a N atom, an O atom, a S atom, etc. For example, "C3-C 10 The term "heteroaryl" refers to a heteroaryl group containing 3 to 10 carbon atoms, which, at each occurrence, can be independently C3 heteroaryl, C4 heteroaryl, C5 heteroaryl, C6 heteroaryl, C7 heteroaryl, C8 heteroaryl, C9 heteroaryl or C 10Heteroaryl. Suitable examples include, but are not limited to, furan, benzofuran, thiophene, benzothiophene, pyrrole, pyrazole, triazole, imidazole, oxazole, oxadiazole, thiazole, tetrazole, indole, carbazole, pyrroloimidazole, pyrrolopyrrole, thienopyrrole, thienothiophene, furopyrrole, furofuran, thienofuran, benzisoxazole, benzisothiazole, benzimidazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, o-naphthyridine, quinoxaline, phenanthridine, primary idine, quinazoline, and quinazolinone.

[0047] The terms "group" and "radical" are considered interchangeable herein.

[0048] The term "substituted or unsubstituted" in this application means that the defined group may be substituted or unsubstituted. When the defined group is substituted, it is understood that the defined group may be substituted by one or more defined substituents R, and when there are multiple substituents, they may be the same or different from each other. The R is selected from, but not limited to, cyano, isocyano, nitro or halogen, alkyl containing 1-4 C atoms, cycloalkyl containing 3-6 C atoms, -NR'R", silane, carbonyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, haloformyl, formyl, isocyanate, thiocyanate, isothiocyanate, hydroxyl, trifluoromethyl; it is understandable that R' and R" in -NR'R" are independently selected from, but not limited to, hydrogen, cyano, isocyano, nitro or halogen, alkyl containing 1-4 C atoms, cycloalkyl containing 3-6 C atoms.

[0049] The "leaving group" can be exemplified by a halogen atom, a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group and a p-toluenesulfonyloxy group.

[0050] In the present application, "aromatic group", "aryl", "aromatic group", "aromatic series" and "aromatic ring system" have the same meaning and can be interchanged; "heteroaryl", "heteroaromatic group", "heteroaromatic series" and "heteroaromatic ring system" have the same meaning and can be interchanged.

[0051] In the present application, a carbonyl group refers to -C(=O)-, a hydroxyl group refers to -OH, and an olefinic bond refers to -(=)-.

[0052] In the present application, "suitable combinations of the aforementioned groups" refers to all suitable combinations with any of the aforementioned items.

[0053] In the present application, "respectively independently selected from..." means that when more than one hydrogen on a group is replaced by a substituent, the substituents may be of the same or different types, and the substituents selected are each independently of the other.

[0054] In one aspect of the present application, a pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof is provided; the pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof has an inhibitory effect on 3CLpro.

[0055] "Pharmaceutically acceptable" refers to those compounds, materials, compositions and / or dosage forms that are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and animals without excessive toxicity, irritation, allergic response or other problems or complications, commensurate with a reasonable benefit / risk ratio.

[0056] "Pharmaceutically acceptable salts" refer to salts of compounds of the present application, prepared from compounds with specific substituents discovered in the present application and relatively non-toxic acids or bases. When the compounds of the present application contain relatively acidic functional groups, base addition salts can be obtained by contacting such compounds with a sufficient amount of base in a pure solution or a suitable inert solvent. Pharmaceutically acceptable base addition salts include sodium, potassium, calcium, ammonium, organic amine or magnesium salts or similar salts. When the compounds of the present application contain relatively basic functional groups, acid addition salts can be obtained by contacting such compounds with a sufficient amount of acid in a pure solution or a suitable inert solvent. Examples of pharmaceutically acceptable acid addition salts include inorganic acid salts, such as hydrochloric acid, hydrobromic acid, nitric acid, carbonic acid, bicarbonate, phosphoric acid, monohydrogen phosphate, dihydrogen phosphate, sulfuric acid, hydrogen sulfate, hydroiodic acid, phosphorous acid, etc.; and organic acid salts, such as formic acid, acetic acid, propionic acid, isobutyric acid, maleic acid, malonic acid, benzoic acid, succinic acid, suberic acid, fumaric acid, lactic acid, mandelic acid, phthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, tartaric acid and methanesulfonic acid and the like; also include salts of amino acids (such as arginine, etc.), and salts of organic acids such as glucuronic acid. Certain specific compounds of the present application contain basic and acidic functional groups, and thus can be converted into any base or acid addition salt. The pharmaceutically acceptable salts of the present application can be synthesized by conventional chemical methods from parent compounds containing acid radicals or bases. Generally, such salts are prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or an organic solvent, or a mixture of both.

[0057] Specifically, the pentacyclic triterpenoid compound is selected from the compound of formula (I) or the compound of formula (II);

[0058]

[0059] R 1 Selected from hydroxyl or

[0060] R 2 , R 3 and R4 are independently selected from: hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C 10 Aryl, substituted or unsubstituted C3~C 10 Heteroaryl, or a suitable combination of C1-C4 alkylene or olefinic bond and the aforementioned groups;

[0061] The pentacyclic triterpenoid compounds do not include R 1 is selected from hydroxyl and R 2 A compound I-1 selected from hydrogen;

[0062]

[0063] In some embodiments, R 1 Selected from hydroxyl groups.

[0064] In some embodiments, R 1 Selected from

[0065] R 4 Selected from: hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C 10 Aryl, substituted or unsubstituted C3~C 10 Heteroaryl, or olefinic bond with substituted or unsubstituted C6~C 10 Aromatic combinations.

[0066] Furthermore, R 4 Selected from methyl, substituted or unsubstituted phenyl, or substituted or unsubstituted pyridyl; wherein the substituent in the substitution scheme is selected from methoxy or halogen.

[0067] Furthermore, R 4 Selected from Where Y is an olefinic bond, and ring A is a substituted or unsubstituted C6~C 10 Aryl.

[0068] Furthermore, ring A is selected from substituted or unsubstituted phenyl groups.

[0069] Furthermore, ring A is phenyl.

[0070] In some embodiments, R 3 Selected from: hydrogen, substituted or unsubstituted C1-C6 alkyl, or substituted or unsubstituted C3-C8 cycloalkyl.

[0071] In some embodiments, R 3 Selected from: hydrogen, substituted or unsubstituted C1-C4 alkyl, or substituted or unsubstituted C3-C6 cycloalkyl.

[0072] In some embodiments, R 3 is selected from hydrogen, methyl or ethyl.

[0073] In some embodiments, R 2 , R 3 and R 4 Each of the following is independently selected from: -H, -D, substituted or unsubstituted C1-C4 alkyl, substituted or unsubstituted C3-C6 cycloalkyl, and substituted or unsubstituted phenyl.

[0074] In some embodiments, the pentacyclic triterpenoid compound is selected from the compound of formula (I) and the definition of each group is selected from any one of the following groups:

[0075] (1)R 1 is hydroxyl group, R 2 is ethyl;

[0076] (2)R 1 for R 4 It is hydroxyl.

[0077] In some embodiments, the pentacyclic triterpenoid compound is selected from the compound of formula (II), R 3 It is ethyl.

[0078] In some embodiments, the pentacyclic triterpenoid compound is selected from the following structures:

[0079]

[0080]

[0081] In yet another aspect of the present application, a method for preparing the pentacyclic triterpenoid compounds described in the first aspect of the present application is provided.

[0082] The preparation method of the compound of formula (I) comprises the following steps:

[0083]

[0084] Take a compound of formula (I-1) and a compound R 11 -X1 undergoes esterification reaction to obtain a compound of formula (I-2), and the compound of formula (I-2) and compound Esterification reaction is carried out to obtain a compound of formula (I-3), or

[0085] Take the compound of formula (I-1) and the compound Carry out esterification reaction to obtain a compound of formula (I-4);

[0086] Take the compound of formula (I-4) and compound R 14 -X2 undergoes esterification reaction to obtain a compound of formula (I-5);

[0087] in,

[0088] R 12 and R 13 As R 1 Definition of;

[0089] R 11 and R 14 As R 2 Definition of;

[0090] X1 and X2 are independently selected from halogen;

[0091] N1 and N2 are each independently selected from a leaving group.

[0092] The preparation method of the compound of formula (II) comprises the following steps:

[0093]

[0094] Take a compound of formula (I-1) and a compound R 15 -X3 undergoes esterification reaction to obtain a compound of formula (I-6),

[0095] Taking the compound of formula (I-6) and subjecting it to oxidation reaction, oxidizing the hydroxyl group therein to keto group, to prepare the compound of formula (II-1);

[0096] Among them, R 15 The definition of R 3 ;

[0097] X3 is selected from halogen.

[0098] In some embodiments, the esterification reaction is carried out in the presence of a base at 20°C to 50°C; optionally, the base for the esterification reaction is selected from one or more of triethylamine, pyridine, diisopropylethylamine, 4-(N,N-dimethyl)aminopyridine and potassium carbonate; optionally, the solvent for the esterification reaction is selected from one or more of dichloromethane, chloroform, N,N-dimethylformamide, tetrahydrofuran and acetonitrile.

[0099] In some embodiments, the oxidation reaction is carried out in the presence of an oxidant PCC at 10°C to 35°C; optionally, the solvent for the oxidation reaction is selected from one or more of dichloromethane, chloroform, N,N-dimethylformamide, tetrahydrofuran and acetonitrile.

[0100] In some embodiments, the esterification reaction is carried out in the presence of a base at 40°C to 80°C; optionally, the base for the esterification reaction is selected from one or more of triethylamine, pyridine, diisopropylethylamine, 4-(N,N-dimethyl)aminopyridine and potassium carbonate; optionally, the solvent for the esterification reaction is selected from one or more of dichloromethane, chloroform, N,N-dimethylformamide, tetrahydrofuran and acetonitrile.

[0101] The present application also relates to a pharmaceutical composition comprising:

[0102] 1) the pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof as described in any of the above technical solutions; and

[0103] 2) Pharmaceutically acceptable carrier.

[0104] "Pharmaceutical composition" refers to a composition that has a pharmaceutical preventive and / or therapeutic effect and can be used in medicine.

[0105] "Pharmaceutically acceptable carrier" refers to a pharmaceutically acceptable material, composition or vehicle, such as a liquid or solid filler, diluent, excipient, solvent or encapsulating material. As used herein, the language "pharmaceutically acceptable carrier" includes buffers, sterile water for injection, solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like that are compatible with drug administration. Each substance must be "pharmaceutically acceptable" in the sense of being compatible with the other ingredients in the formulation and not harmful to the patient. Suitable examples include, but are not limited to: (1) sugars such as lactose, glucose and sucrose; (2) starches such as corn starch, potato starch and substituted or unsubstituted β-cyclodextrins; (3) cellulose and its derivatives such as sodium carboxymethylcellulose, ethylcellulose and cellulose acetate; (4) powdered tragacanth; (5) malt; (6) gelatin; (7) talc; (8) excipients such as cocoa butter and suppository waxes; (9) oils such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn starch, etc. Rice oil and soybean oil; (10) glycols, such as propylene glycol; (11) polyols, such as glycerol, sorbitol, mannitol and polyethylene glycol; (12) esters, such as ethyl oleate and ethyl laurate; (13) agar; (14) buffers, such as magnesium hydroxide and aluminum hydroxide; (15) alginic acid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer's solution; (19) ethanol; (20) phosphate buffered saline; and (21) other non-toxic compatible substances used in pharmaceutical formulations.

[0106] The present application also relates to the use of the above-mentioned pentacyclic triterpenoid compounds or pharmaceutically acceptable salts thereof in the preparation of drugs; the drugs are selected from: 1) drugs for preventing and / or treating coronavirus infections, and 2) drugs for preventing and / or treating small RNA virus infections.

[0107] "Drug" includes any agent, compound, composition or mixture that provides physiological and / or pharmacological effects in vivo or in vitro, and often provides beneficial effects. The scope of the physiological and / or pharmacological effects produced by the "drug" in vivo is not particularly limited, and may be systemic effects or may only produce effects locally. The activity of the "drug" is not particularly limited, and may be an active substance that can interact with other substances, or an inert substance that does not interact.

[0108] The pentacyclic triterpenoid compound or its pharmaceutically acceptable salt in the present application has the activity of inhibiting coronavirus 3CL protease and 3CL protease of small RNA virus. Therefore, the present application also relates to a 3CL protease inhibitor, which comprises the above-mentioned pentacyclic triterpenoid compound or its pharmaceutically acceptable salt, or the above-mentioned pharmaceutical composition (comprising a therapeutically effective amount of pentacyclic triterpenoid compound or its pharmaceutically acceptable salt). In some embodiments, the 3CL protease inhibitor includes a coronavirus 3CL protease inhibitor and a small RNA virus 3CL protease inhibitor.

[0109] The present application also relates to the use of a pharmaceutical composition containing a therapeutically effective amount of the above-mentioned pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof in the preparation of a drug; the drug is selected from: 1) a drug for preventing and / or treating coronavirus infection, and 2) a drug for preventing and / or treating small RNA virus infection.

[0110] The definitions of "pharmaceutical composition", "drug", etc. are consistent with the above.

[0111] "Therapeutically effective amount" refers to the amount of a pharmaceutically active ingredient that will elicit a biological or medical response in an individual to a disease, disorder and / or symptom, for example, the amount of a compound of the present application that brings about a physiologically and / or pharmacologically positive effect in an individual, wherein the physiologically and / or pharmacologically positive effect includes but is not limited to reducing or inhibiting enzyme or protein activity or improving symptoms, alleviating symptoms, slowing or delaying disease progression or preventing disease, etc.

[0112] According to the above application, the present application also provides a method for preventing and / or treating a disease or condition, which comprises administering a therapeutically effective amount of a pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof to a patient in need; that is, administering a therapeutically effective amount of a pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof to a patient; the disease or condition is a 3CL protease-mediated disease or condition, particularly a disease or condition associated with coronavirus infection and / or small RNA virus infection. Coronaviruses include SARS-CoV, MERS-CoV, H229E-CoV, HKU1-CoV, NL63-CoV, OC43-CoV, SARS-CoV-2, and the like.

[0113] Application method

[0114] The pentacyclic triterpene derivatives obtained by the present application can be administered to humans orally, rectally, parenterally (intravenously, intramuscularly or subcutaneously), or topically (powders, ointments or drops).

[0115] Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules. In these solid dosage forms, the active compound is mixed with at least one conventional inert excipient (or carrier), such as sodium citrate or dicalcium phosphate, or with the following ingredients: (a) fillers or extenders, for example, starches, lactose, sucrose, glucose, mannitol, and silicic acid; (b) binders, for example, hydroxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone, sucrose, and acacia; (c) humectants, for example, glycerol; (d) disintegrants, for example, agar, calcium carbonate, potato starch or tapioca starch, alginic acid, certain complex silicates, and sodium carbonate; (e) solubilizers, for example, paraffin; (f) absorption accelerators, for example, quaternary ammonium compounds; (g) wetting agents, for example, cetyl alcohol and glyceryl monostearate; (h) adsorbents, for example, kaolin; and (i) lubricants, for example, talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, or mixtures thereof. In the case of capsules, tablets and pills, the dosage forms may also comprise buffering agents.

[0116] Solid dosage forms such as tablets, pills, capsules, pills and granules can be prepared using coatings and shell materials, such as enteric coatings and other materials known in the art. They may contain opacifiers, and the release of the active compound or compounds in such compositions can be delayed in a certain part of the digestive tract. Examples of embedding components that can be used are polymeric substances and waxes. If necessary, the active compound can also be formed into microencapsulated form with one or more of the above-mentioned excipients.

[0117] Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups or tinctures. In addition to the active compound, the liquid dosage form may contain an inert diluent conventionally used in the art, such as water or other solvents, solubilizers and emulsifiers, for example, ethanol, isopropanol, ethyl carbonate, ethyl acetate, propylene glycol, 1,3-butylene glycol, dimethylformamide and oils, in particular cottonseed oil, peanut oil, corn germ oil, olive oil, castor oil and sesame oil or mixtures of these substances.

[0118] Besides these inert diluents, the above composition may also contain adjuvants such as wetting agents, emulsifying and suspending agents, sweetening agents, flavoring agents and perfumes.

[0119] Suspensions, in addition to the active compounds, may contain suspending agents such as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum methanol and agar, or mixtures of these substances, and the like.

[0120] Compositions for parenteral injection may include physiologically acceptable sterile aqueous or anhydrous solutions, dispersions, suspensions or emulsions, and sterile powders for reconstitution into sterile injectable solutions or dispersions. Suitable aqueous and non-aqueous carriers, diluents, solvents or excipients include water, ethanol, polyols and suitable mixtures thereof.

[0121] Dosage forms for topical administration of the compounds of the present application include ointments, powders, sprays and inhalants. The active ingredient is mixed under sterile conditions with a physiologically acceptable carrier and any preservatives, buffers, or propellants that may be required.

[0122] The present application is further described below in conjunction with specific embodiments, but the present application is not limited thereto.

[0123] In the following embodiments, 1 H-NMR was measured using a Varian Mercury AMX 500 instrument. MS was measured using a VG ZAB-HS or VG-7070 and Esquire 3000plus-01005. All solvents were redistilled before use, and the anhydrous solvents used were obtained by drying according to standard methods. Unless otherwise specified, all reactions were carried out under argon protection and tracked by TLC. Post-treatments were performed by washing with saturated brine and drying with anhydrous magnesium sulfate. Unless otherwise specified, the products were purified using silica gel column chromatography, and the silica gel used was 200-300 mesh, GF 254 Produced by Qingdao Ocean Chemical Plant or Yantai Yuanbo Silica Gel Company.

[0124] Betulinic acid: purchased from Anhui Zesheng Technology Co., Ltd., product number: E100232-5g.

[0125] 1. Compound preparation part

[0126] Example 1: Synthesis of Compound A1

[0127]

[0128] In a 50 mL round-bottom flask, betulinic acid (912 mg, 2 mmol) was dissolved in 20 mL of anhydrous N, N-dimethylformamide, and MeI (2 mmol) was added under stirring. The mixture was stirred at room temperature for 5 hours. After the reaction, 50 mL of anhydrous dichloromethane was added. The layers were washed twice with water, then twice with saturated brine, and dried over magnesium sulfate. After filtering to remove magnesium sulfate and concentrating under reduced pressure, white powder A1 (895 mg, 95%) was obtained by column chromatography (PE: EtOAc = 20: 1, v / v / ). 1H NMR (500MHz, CDCl3) δ4.76(s,1H),4.62(s,1H),3.69(s,3H),3.20(dd,J=9.6,3.9Hz,1H),3.02(td,J=9.1,4.1Hz,1H),2.27–2.18( m,3H),1.93–1.88(m,2H),1.70(s,3H),1.66–1.08(m,19H),0.98(s,3H),0.93(s,3H),0.84(s,3H),0.77(s,3H),0.73–0.67(m,3H); 13 C NMR (125MHz, CDCl3) δ176.70,150.62,109.60,79.00,56.57,55.36,51.30,50.56,49.47,46.99,42.40,40.68,38.88,38.72,38.27,37. 21,36.99,34.33,32.19,30.62,29.69,28.00,27.43,25.52,20.89,19.39,18.31,16.14,15.96,15.38,14.73.ESI-MS(m / z)471.6[M+H] + .

[0129] Example 2: Synthesis of Compound A2

[0130]

[0131] The same operation as the preparation of A1 was used, except that EtI was used as the starting material instead of MeI. White powder A2 (931 mg, 96%) was obtained by column chromatography (PE:EtOAc=20:1, v / v / ). 1 H NMR(500MHz,CDCl3)δ4.76(s,1H),4.62(s,1H),4.23–4.09(m,2H),3.20(dd,J=9.7,4.0Hz,1H),3.03(dd,J=9.3,4.2Hz,1H),2.29–2.20(m,3H),1 .96–1.85(m,2H),1.70(s,3H),1.66–1.02(m,19H),1.28(t,J=5.9Hz,3H) ,0.98(s,3H),0.94(s,3H),0.84(s,3H),0.77(s,3H),0.71–0.68(m,3H); 13C NMR (125MHz, CDCl3) δ176.15,150.72,109.55,79.01,59.80,56.41(C-2) ,55.36,50.58,49.41,47.02,42.41,40.73,38.88,38.73,38.26,37.21, 37.06(C-14),34.33,32.18,30.65,29.63,28.00,27.43,25.56,20.92,1 9.40,18.31,16.15,15.98,15.38,14.72,14.37.ESI-MS(m / z)485.7[M+H] + .

[0132] Example 3: Synthesis of Compound A3

[0133]

[0134] In a 50 mL round-bottom flask, betulinic acid (912 mg, 2 mmol) was dissolved in 20 mL of anhydrous dichloromethane, and PCC (6 mmol) was added under stirring. The mixture was stirred at room temperature for 6 hours. After the reaction, 20 mL of anhydrous dichloromethane was added. The layers were washed twice with water, and then with saturated brine, and dried over magnesium sulfate. After filtering to remove magnesium sulfate and concentrating under reduced pressure, white powder A3 (835 mg, 92%) was obtained by column chromatography (PE: EtOAc = 20: 1, v / v / ). 1 H NMR (500MHz, CDCl3) δ4.77 (s, 1H), 4.64 (s, 1H), 3.04 (td, J = 10.8, 4.8Hz), 2 .56–2.38(m,2H),2.34–2.20(m,2H),2.06–1.97(m,2H),1.93(ddd,J=12.5,7 .6,4.4Hz,1H),1.72(s,1H),1.68(s,3H),1.65(d,J=11.4Hz,1H),1.60–1.2 1(m,14H),1.10(s,3H),1.04(s,3H),1.02(s,3H),1.00(s,3H),0.95(s,3H); 13CNMR(125MHz, CDCl3)δ218.90,151.02,110.49,57.08,55.65,50.56,49.90,48.05,47.59,43.20,41.34,40.32,39.21,37.74,37 .63,34.85,34.31,32.80,31.25,30.39,27.35,26.20,22.08,21.71,20.34,20.08,16.67,16.53,15.33.ESI-MS(m / z)455.6[M+H] + .

[0135] Example 4: Synthesis of Compound A4

[0136]

[0137] The same operation as the preparation of A3 was used, except that A1 was used as the starting material instead of betulinic acid. White powder A4 (749 mg, 80%) was obtained after column chromatography (PE:EtOAc=20:1, v / v / ). 1 H NMR(500MHz, CDCl3)δ4.76(s,1H),4.63(s,1H),3.70(s,3H),3.02(td,J=10.9,4.4Hz,1H),2.56–2.38(m,2H),2.30–2.22(m,2H),1.96–1.89(m ,3H),1.71(s,1H),1.64(s,3H),1.61(d,J=11.3Hz,1H),1.52–1.17(m, 14H),1.09(s,3H),1.04(s,3H),1.00(s,3H),0.98(s,3H),0.95(s,3H); 13 C NMR (125MHz, CDCl3) δ218.85,177.34,151.22,110.35,57.24,55.70,52.01,50.62,50.10,48.06,47.65,43.16,41.33,40.34,39.05,37 .65,37.62,34.87,34.33,32.82,31.29,30.37,27.31,26.23,22.12,21.75,20.35,20.09,16.65,16.47,15.34.ESI-MS(m / z)469.6[M+H] + .

[0138] Example 5: Synthesis of Compound A5

[0139]

[0140] The preparation procedure was the same as that of A3, except that A2 was used as the starting material instead of betulinic acid. White powder A5 (711 mg, 73%) was obtained by column chromatography (PE:EtOAc=20:1, v / v / ). 1 H NMR(500MHz, CDCl3): δ4.76(s,1H),4.62(s,1H),4.23–4.11(m,2H),3.04(td, J=10.9,4.5Hz,1H),2.57–2.37(m,2H),2.32–2.24(m,2H),1.97–1.88(m,3H),1 .71(s,3H),1.64(s,3H),1.61(d,J=11.3Hz,1H),1.60–1.25(m,14H),1.29(t,J =7.1Hz,3H),1.09(s,3H),1.04(s,3H),1.00(s,3H),0.98(s,3H),0.95(s,3H); 13 C NMR (126MHz, CDCl3): δ218.89,176.80,151.32,110.30,60.52,57.08,55.69,50.64,50.04,48.05,47.68,43.17,41.38,40.35,39.03,37.72 ,37.62,34.87,34.33,32.81,31.33,30.30,27.32,26.26,22.15,21.7 4,20.35,20.09,16.67,16.48,15.33,15.06.ESI-MS(m / z)483.7[M+H] + .

[0141] Example 6: Synthesis of Compound A6

[0142]

[0143] In a 50 mL round-bottom flask, betulinic acid (912 mg, 2 mmol) was dissolved in 20 mL of N, N-dimethylformamide, and 3 mL of pyridine and 1 mL of acetic anhydride were added under stirring. The mixture was stirred at room temperature for 5 hours. After the reaction, 50 mL of anhydrous dichloromethane was added. The layers were washed with water 3 times, then with saturated brine 3 times, and dried over magnesium sulfate. After filtering to remove magnesium sulfate and concentrating under reduced pressure, white powder A6 (847 mg, 85%) was obtained by column chromatography (PE: EtOAc = 20: 1, v / v / ). 1H NMR (500MHz, CDCl3): δ4.76 (s, 1H), 4.64 (s, 1H), 4.50 (dd, J = 10.7, 5.7Hz, 1H), 3.03(td,J=10.7,4.7Hz,1H,2.30(dt,J=12.9,3.4Hz,2H),2.21(td,J=12.3,3.6 Hz,1H),2.07(s,3H),2.05–1.96(m,2H),1.72(s,3H),1.69–1.17(m,19H),1.00 (s,3H),0.96(s,3H),0.88(s,3H),0.87(s,3H),0.85(s,3H),0.84–0.80(m,1H); 13 C NMR (126MHz, CDCl3): δ182.68,171.78,151.09,110.46,81.66,57.10,56.12,51.10,49.97,47.65,43.13,41.40,39.12,39.09,38.51,37.83 ,37.75,34.94,32.86,31.27,30.40,28.66,26.15,24.41,22.04,21.5 6,20.06,18.87,17.18,16.89,16.74,15.37.ESI-MS(m / z)499.6[M+H] + .

[0144] Example 7: Synthesis of Compound A7

[0145]

[0146] The preparation procedure was the same as that of A6, except that A1 was used as the starting material instead of betulinic acid. White powder A7 (860 mg, 84%) was obtained by column chromatography (PE:EtOAc=20:1, v / v / ). 1 H NMR (500MHz, CDCl3): δ4.76 (s, 1H), 4.63 (s, 1H), 4.49 (dd, J = 10.5, 5.8Hz, 1H) ,3.69(s,3H),3.02(td,J=10.9,4.4Hz,1H),2.28–2.18(m,3H),2.06(s,3H),1 .97–1.86(m,2H),1.71(s,3H),1.66–1.01(m,19H),0.98(s,3H,31-H),0.94(s ,3H),0.86(d,J=1.8Hz,6H,29-H,28-H),0.85(s,3H,30-H),0.83–0.77(m,1H); 13C NMR (126MHz, CDCl3): δ177.38,171.73,151.28,110.33,81.65,57.27,56.14,51.97,51.16,50.16,47.70,43.09,41.40,39.10,38.96,38.51,37 .82,37.67,34.96,32.87,31.30,30.37,28.65,26.18,24.41,22.04,21 .60,20.05,18.89,17.20,16.89,16.66,15.38.ESI-MS(m / z)513.6[M+H] + .

[0147] Example 8: Synthesis of Compound A8

[0148]

[0149] The preparation procedure was the same as that of A6, except that A2 was used as the starting material instead of betulinic acid. White powder A8 (747 mg, 71%) was obtained by column chromatography (PE:EtOAc=20:1, v / v / ). 1 H NMR (500MHz, CDCl3): δ4.76 (s, 1H), 4.62 (s, 1H), 4.49 (dd, J = 10.8, 5.6Hz, 1H), 4. 24–4.09(m,2H),3.03(td,J=10.8,4.6Hz,1H),2.29–2.20(m,3H),2.06(s,3H),1. 96–1.87(m,2H),1.71(s,3H),1.66–1.13(m,19H),1.29(t,J=7.1Hz,3H),0.98(s, 3H),0.94(s,3H,27-H),0.86(d,6H,29-H,28-H),0.85(s,3H),0.83–0.79(m,1H); 13 C NMR (126MHz, CDCl3): δ176.84,171.74,151.38,110.28,81.66,60.47,57. 10,56.14,51.18,50.10,47.74,43.10,41.45,39.11,38.94,38.51,37.82 ,37.75,34.96,32.86,31.34,30.31,28.65,26.21,24.41,22.04,21.63,2 0.06,18.88,17.20,16.90,16.67,15.37,15.06.ESI-MS(m / z)527.7[M+H] + .

[0150] Example 9: Synthesis of Compound A9

[0151]

[0152] In a 50 mL round-bottom flask, betulinic acid (912 mg, 2 mmol) was dissolved in 20 mL of N, N-dimethylformamide, and 3 mL of pyridine and 1 mL of acetic anhydride were added under stirring. The mixture was stirred at room temperature for 5 hours. After the reaction, 50 mL of anhydrous dichloromethane was added. The layers were washed with water 3 times, then with saturated brine 3 times, and dried over magnesium sulfate. After filtering to remove magnesium sulfate and concentrating under reduced pressure, white powder A6 (986 mg, 88%) was obtained by column chromatography (PE: EtOAc = 15: 1, v / v). 1 HNMR (500MHz, DMSO-d6): δ12.04(s,1H),7.92(d,2H),7.62(s,1H),7.50(t,J= 6.3Hz,2H),4.67(d,1H),4.59(dd,J=11.4,4.5Hz,1H),4.54(s,1H),2.92(t,J =8.7,3.9Hz,1H),2.12–2.05(m,3H,3-H),1.83–1.73(m,2H),1.62(s,3H),1.5 4–1.04(m,19H),0.93(d,J=4.3Hz,6H),0.86(s,3H),0.83(s,3H),0.78(s,3H); 13 C NMR (126MHz, DMSO-d6): δ177.71,165.81,150.78,133.70,130.65,129.49,12 9.26,110.14,81.44,55.89,55.07,50.13,49.00,47.09,42.53,40.74,38.21 ,38.05,37.16,36.80,36.20,32.16,30.57,29.69,28.25,27.68,25.03,23.8 2,20.95,19.42,18.22,17.08,16.36,16.17,14.85.ESI-MS(m / z)561.7[M+H] + .

[0153] Example 10: Synthesis of Compound A10

[0154]

[0155] The preparation procedure was the same as that of A9, except that A1 was used as the starting material instead of betulinic acid. White powder A10 (975.8 mg, 85%) was obtained by column chromatography (PE:EtOAc=20:1, v / v / ). 1 H NMR (500MHz, CDCl3): δ8.06 (d, J=7.3Hz, 2H), 7.57 (t, J=7.5Hz, 1H), 7.46 (t, J= 7.7Hz,2H),4.79–4.71(m,2H),4.63(s,1H),3.70(s,3H,38-H),3.03(td,J=10. 9,4.7Hz,1H),2.28-2.20(m,3H),1.96–1.87(m,2H),1.72(s,3H,26-H),1.66–1 .04(m,19H),1.02(s,3H),1.01(s,3H),0.96(s,3H),0.94(s,3H),0.92(s,3H); 13 C NMR (126MHz, CDCl3): δ176.69,166.30,150.58,132.70,131.01,129.53,128.3 1,109.65,81.60,56.57,55.51,51.28,50.48,49.47,47.01,42.43,40.73,38. 42,38.28,38.22,37.18,36.98,34.27,32.18,30.61,29.69,28.12,25.49,23. 77,20.94,19.36,18.22,16.80,16.21,15.98,14.72.ESI-MS(m / z)575.7[M+H] + .

[0156] Example 11: Synthesis of Compound A11

[0157]

[0158] The preparation procedure was the same as that of A9, except that A2 was used as the starting material instead of betulinic acid. White powder A11 (1058 mg, 90%) was obtained by column chromatography (PE:EtOAc=20:1, v / v). 1 H NMR (500MHz, CDCl3): δ8.06(d,J=6.8Hz,2H),7.57(t,J=7.4Hz,1H),7.46(t,J=7.7Hz,2H),4.79– 4.71(m,2H),4.63(s,1H),4.24–4.10(m,2H),3.04(td,J=10.8,4.5Hz,1H),2.30–2.22(m,3H,3-H a,18-H),1.98–1.87(m,2H,19-H a ,20-H a ),1.72(s,3H),1.66–1.04(m,19H),1.29(t,J=7.1Hz,3H,47-H),1.02(s,3H,29-H),1.01(s,3H),0.97(s,3H),0.94(s,3H),0.92(s,3H); 13 C NMR (126MHz, CDCl3): δ176.15,166.31,150.68,132.70,131.01,129.53,128.31 ,109.60,81.61,59.78,56.41,55.52,50.50,49.41,47.05,42.44,40.78,38.43, 38.26,38.22,37.18,37.06,34.27,32.17,30.64,29.62,28.12,25.53,23.77,2 0.96,19.37,18.22,16.79,16.22,16.00,14.71,14.37.ESI-MS(m / z)589.8[M+H] + .

[0159] Example 12: Synthesis of Compound A12

[0160]

[0161] The same operation as the preparation of A9 was used, except that benzoyl chloride was replaced by p-methoxybenzoyl chloride, and betulinic acid was replaced by A1. White powder A12 (1025 mg, 85%) was obtained by column chromatography (PE:EtOAc=20:1, v / v).

[0162] 1 H NMR (500MHz, CDCl3): δ7.97(d,J=7.4Hz,2H), 6.90(d,J=7.4Hz,2H), 4.73(d,J=2.3Hz, 1H),4.66(dd,J=9.5,4.1Hz,1H),4.59(s,1H),3.84(s,3H),3.66(s,3H),2.99(td,J=8. 9,4.0Hz,1H),2.24–2.16(m,3H),1.91–1.84(m,2H),1.68(s,3H),1.59(d,J=9.5Hz,1H) ,1.57–0.98(m,19H),0.96(s,3H),0.92(s,3H),0.89(s,3H),0.87(s,3H),0.85(s,3H); 13C NMR (126MHz, CDCl3): δ176.69,166.08,163.18,150.58,131.51,123.47,113.55,109 .65,81.18,56.58,55.52,55.43,51.27,50.48,49.48,47.02,42.43,40.73,38.43,38 .28,38.21,37.17,36.98,34.28,32.19,30.61,29.69(C-4),28.12,25.50,23.82,20 .94,19.36(C-29),18.23(C-8),16.80,16.20,15.98,14.72.ESI-MS(m / z)604.7[M+H] + .

[0163] Example 13: Synthesis of Compound A13

[0164]

[0165] The same operation as the preparation of A9 was used, except that benzoyl chloride was replaced by p-methoxybenzoyl chloride, and betulinic acid was replaced by A2. White powder A13 (1112 mg, 90%) was obtained by column chromatography (PE:EtOAc=20:1, v / v). 1 H NMR (500MHz, CDCl3): δ7.97 (d, J = 7.4Hz, 2H), 6.90 (d, J = 7.4Hz, 2H), 4.72 (d, J = 2.4Hz, 1H), 4. 67(dd,J=9.7,4.3Hz,1H),4.59(s,1H),4.20–4.06(m,2H),3.84(s,3H),3.00(td,J=8.9,4.0Hz ,1H),2.26–2.17(m,3H),1.94–1.82(m,2H),1.68(s,3H),1.59(d,J=9.5Hz,1H),1.25(t,J=5.9 Hz,3H),1.53–0.99(m,19H),0.97(s,3H),0.96(s,3H),0.92(s,3H),0.89(s,3H),0.87(s,3H); 13C NMR (126MHz, CDCl3): δ176.15,166.08,163.18,150.68,131.51,123.47,113.55,1 09.59,81.18,59.78,56.41,55.52,55.43,50.50,49.42,47.05,42.44,40.78,38. 43,38.26,38.21,37.17,37.06,34.28,32.18,30.65,29.62,28.12,25.53,23.83, 20.96,19.37,18.22,16.80,16.21,16.00,14.71,14.36.ESI-MS(m / z)619.8[M+H] + .

[0166] Example 14: Synthesis of Compound A14

[0167]

[0168] The same operation as the preparation of A9 was used, except that p-chlorobenzoyl chloride was used instead of benzoyl chloride, and A1 was used instead of betulinic acid. White powder A14 (1094 mg, 90%) was obtained by column chromatography (PE:EtOAc=20:1, v / v / ). 1 H NMR (500MHz, CDCl3): δ7.99(d,J=8.6Hz,2H),7.43(d,J=8.4Hz,2H),4.80-4.70(m,2H),4.63(s,1H),3.70(s,3H),3.03(td,J=10.9,4.6Hz, 1H),2.29–2.19(m,3H),1.98–1.86(m,2H),1.72(s,3H),1.66–1.03(m,19H),1.00(d,J=1.5Hz,6H),0.96(s,3H),0.93(s,3H),0.92(s,3H); 13C NMR (126MHz, CDCl3): δ176.19,164.95,150.08,138.63,130.42,128.93,128.1 6,109.16,81.48,56.07,55.00,50.79,49.98,48.97,46.51,41.93,40.23,37. 90,37.77,37.70,36.67,36.48,33.76,31.68,30.11,29.19,27.63,24.99,23. 26,20.44,18.87,17.72,16.30,15.70,15.48,14.22.ESI-MS(m / z)609.8[M+H] + .

[0169] Example 15: Synthesis of Compound A15

[0170]

[0171] The same operation as the preparation of A9 was used, except that benzoyl chloride was replaced by p-chlorobenzoyl chloride and betulinic acid was replaced by A2. White powder A15 (1144 mg, 92%) was obtained by column chromatography (PE:EtOAc=20:1, v / v).

[0172] 1 H NMR (500MHz, CDCl3): δ7.99 (d, J=8.7Hz, 2H), 7.43 (d, J=8.6Hz, 2H), 4.80–4. 70(m,2H),4.63(s,1H),4.24–4.10(m,2H),3.04(td,J=10.8,4.5Hz,1H),2.30 –2.22(m,3H),1.97–1.88(m,2H),1.72(s,3H),1.66–1.04(m,19H),1.30(t,J= 7.1Hz,3H),1.01(s,3H),1.00(s,3H),0.97(s,3H),0.93(s,3H),0.92(s,3H); 13C NMR (126MHz, CDCl3): δ175.64,164.96,150.18,138.63,130.42,128.94,128.16 ,109.10,81.48,59.29,55.91,55.00,50.00,48.91,46.55,41.94,40.28,37.91, 37.75,37.71,36.67,36.56,33.76,31.67,30.15,29.13,27.63,25.03,23.26,2 0.47,18.88,17.71,16.30,15.71,15.50,14.21,13.87.ESI-MS(m / z)623.8[M+H] + .

[0173] Example 16: Synthesis of Compound A16

[0174]

[0175] The same operation as the preparation of A9 was used, except that pyridine-4-carbonyl chloride was used instead of benzoyl chloride, and A1 was used instead of betulinic acid. White powder A16 (1023 mg, 89%) was obtained by column chromatography (PE:EtOAc=20:1, v / v / ).

[0176] 1 H NMR (500MHz, CDCl3): δ8.80(d,J=5.2Hz,2H),7.86(d,J=6.0Hz,2H),4.81–4.72(m,2H),4.63(d,J=2.4Hz,1H),3.70(s,3H,46-H),3.03(td,J=10.9,4 .4Hz,1H),2.29–2.20(m,3H),1.97–1.87(m,2H),1.72(s,3H),1.65–1.04( m,19H),1.01(s,3H),1.00(s,3H),0.96(s,3H),0.94(s,3H),0.92(s,3H); 13C NMR (126MHz, CDCl3): δ176.17,164.29,150.07,137.68,122.38,109.16,8 2.33,56.07,54.98,50.79,49.98,48.97,46.50,41.93,40.22,37.87,37.7 5,37.71,36.66,36.48,33.74,31.67,30.11,29.19,27.63,24.98,23.18, 20.45,18.87,17.71,16.26,15.70,15.48,14.21.ESI-MS(m / z)576.7[M+H] + .

[0177] Example 17: Synthesis of Compound A17

[0178]

[0179] The same operation as the preparation of A9 was used, except that pyridine-4-carbonyl chloride was used instead of benzoyl chloride, and A2 was used instead of betulinic acid. White powder A17 (1060 mg, 90%) was obtained by column chromatography (PE:EtOAc=20:1, v / v).

[0180] 1 H NMR (500MHz, CDCl3): δ8.80(d,J=5.2Hz,2H),7.86(d,J=6.0Hz,2H),4.80–4.73(m, 2H),4.63(s,1H),4.25–4.09(m,2H),3.04(td,J=10.9,4.5Hz,1H),2.30–2.23(m,3H ),1.97–1.88(m,2H),1.72(s,3H,26-H),1.67–1.12(m,19H),1.29(t,J=7.1Hz,3H), 1.01(s,3H,29-H),1.01(s,3H,28-H),0.97(s,3H,31-H),0.94(s,3H),0.92(s,3H); 13C NMR (126MHz, CDCl3): δ175.63,164.28,150.01,137.70,122.39,109.10,82. 35,59.30,55.90,54.98,50.00,48.90,46.53,41.94,40.28,37.87,37.73,3 7.71,36.66,36.55,33.74,31.66,30.14,29.12,27.63,25.01,23.18,20.47 ,18.88,17.70,16.26,15.71,15.50,14.20,13.87.ESI-MS(m / z)590.8[M+H] + .

[0181] Example 18: Synthesis of Compound A18

[0182]

[0183] The same operation as the preparation of A9 was used, except that cinnamoyl chloride was used as the starting material instead of benzoyl chloride. White powder A18 (1078 mg, 92%) was obtained by column chromatography (PE:EtOAc=15:1, v / v / ). 1 H NMR (500MHz, DMSO-d6): δ12.10(brs,1H),7.73(dd,J=6.7,2.9Hz,2H),7.65(s,1H),7.62( s,1H),7.45–7.41(m,2H),6.64(s,1H),6.60(s,1H),4.71(d,J=2.6Hz,1H),4.58(s,1H),4. 53(dd,J=11.6,4.7Hz,1H),2.96(td,J=10.6,4.9Hz,1H),2.16–2.09(m,3H),1.85–1.76(m ,2H),1.67(s,3H,26-H),1.58–1.07(m,19H),0.97(s,3H),0.90(s,3H),0.87-0.83(m,9H); 13C NMR (126MHz, DMSO-d6): δ177.21,165.95,150.29,144.22,134.00,128.88,128 .33,118.50,109.65,80.17,55.39,54.60,49.63,48.50,46.60,42.02,40.24,3 7.75,37.59,37.55,36.65,36.30,33.71,31.66,30.07,29.19,27.68,25.03,23 .43,20.44,18.93,17.73,16.53,15.90,15.68,14.34.ESI-MS(m / z)587.7[M+H] + .

[0184] Example 19: Synthesis of Compound A19

[0185]

[0186] The same operation as the preparation of A9 was used, except that cinnamoyl chloride was used instead of benzoyl chloride, and A2 was used instead of betulinic acid. White powder A19 (1140 mg, 95%) was obtained by column chromatography (PE:EtOAc=20:1, v / v). 1 H NMR (500MHz, CDCl3): δ7.67(s,2H),7.64(s,1H),7.54–7.51(m,2H,44-H,46-H),7.38(dd,J =5.0,1.9Hz,1H,45-H),6.45(s,1H),6.42(s,1H),4.74(d,J=2.3Hz,2H),4.64–4.59(m,1H) ,3.67(s,3H),3.00(td,J=10.9,4.7Hz,1H),2.25–2.16(m,3H),1.94–1.84(m,2H),1.69(s, 3H),1.63–0.99(m,19H),0.97(s,3H),0.93(s,3H),0.92(s,3H),0.89(s,3H),0.88(s,3H); 13C NMR (126MHz, CDCl3): δ176.24,166.39,150.13,143.80,134.12,128.40,127.59 ,118.44,109.19,80.58,56.12,55.03,50.81,50.03,49.02,46.56,41.96,40.27 ,37.98,37.82,37.61,36.70,36.53,33.82,31.73,30.16,29.23,27.56,25.04,2 3.36,20.47,18.90,17.76,16.21,15.76,15.52,14.25.ESI-MS(m / z)601.7[M+H] + .

[0187] Example 20: Synthesis of Compound A20

[0188]

[0189] The same operation as the preparation of A9 was used, except that cinnamoyl chloride was used instead of benzoyl chloride, and A1 was used instead of betulinic acid. White powder A20 (1101 mg, 94%) was obtained by column chromatography (PE:EtOAc=20:1, v / v). 1 H NMR (500MHz, CDCl3): δ7.67(s,2H),7.64(s,1H),7.56–7.50(m,2H),7.41–7.35(m,1H),6.4 5(s,1H),6.42(s,1H),4.74(d,J=2.3Hz,2H),4.65–4.58(m,1H),4.21–4.08(m,2H),3.01(t d,J=10.8,4.6Hz,1H),2.27–2.18(m,3H),1.96–1.84(m,2H),1.69(s,3H),1.63–0.99(m,19 H),1.27(t,J=7.1Hz,3H),0.97(s,3H),0.93(s,3H),0.91(s,3H),0.89(s,3H),0.87(s,3H); 13C NMR (126MHz, CDCl3): δ175.69,166.39,150.23,143.80,134.12,128.40,127.59,1 18.44,109.13,80.58,59.32,55.96,55.04,50.05,48.96,46.59,41.97,40.32,37 .99,37.80,37.61,36.70,36.60,33.83,31.72,30.19,29.16,27.56,25.08,23.37 ,20.50,18.91,17.75,16.21,15.77,15.53,14.23,13.91.ESI-MS(m / z)587.7[M+H] + .

[0190] 2. In vitro activity test

[0191] 2.1 Experimental Principle

[0192] In vitro enzyme activity assay based on fluorescence resonance energy transfer (FRET) to evaluate the activity of compounds against SARS-CoV-2 3CL pro of the inhibitory activity.

[0193] 2.2. Experimental materials (Table 1)

[0194] Table 1

[0195]

[0196]

[0197] 2.3. Experimental instruments and equipment (Table 2)

[0198] Table 2

[0199] Instrument Name brand model Echo Nano Upgrade Sonic Wave Shift System Labcyte Echo 650 Flexstation 3 Microplate Reader MolecMar Devices FLEX3 Centrifuge Eppendorf 5810

[0200] Experimental procedures

[0201] The volume of the entire enzymatic reaction system is 120 μL, and the protease SARS-CoV-2 3CL proThe final concentration of the substrate (Dacyl-KTSAVLQSGFRKME-Edans) was 10 μM, and the final concentration of the compound was 20 μM, 4 μM, 0.8 μM, and 0.16 μM. The buffer of the reaction system included 50 mM Tris pH 7.3 and 1 mM EDTA. In the experiment, 40 μL of SARS-CoV-2-3CL was added to a black 96-well plate. pro The sample was mixed with 40 μL of compound samples of different concentrations, incubated at room temperature for 10 minutes, and 40 μL of substrate diluent was added and quickly placed in the BioTek Synergy-H1 microplate reader for reading. The excitation light and emission light were 340 nm and 490 nm, respectively. The test time was 5 minutes, and the fluorescence value was read every 1 minute. The final result was to fit the reaction rate with the fluorescence reading within 5 minutes, and compared with the control group (DMSO), and the inhibition rate was calculated. The calculation formula is as follows:

[0202] 3CL pro Inhibition rate (%) = (V ct -V comd ) / V ct ×100%

[0203] Among them, V ct is the fluorescence intensity increase value of the control group, V Comd Add values ​​for the fluorescence intensity of the test sample.

[0204] Compounds against SARS-CoV-2 3CL pro The results of inhibition rate activity evaluation are shown in Table 3:

[0205] Table 3 Effects of some compounds on SARS-CoV-2 3CL pro Inhibitory activity

[0206]

[0207]

[0208] 2.5 Experimental results

[0209] For the 3CL protease with P132H mutation in the SARS-CoV-2 Omicron strain, multiple betulinic acid derivatives showed strong inhibitory activity.

[0210] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0211] The technical features of the above-mentioned implementation modes and examples can be combined in any appropriate manner. To make the description concise, not all possible combinations of the technical features in the above-mentioned implementation modes and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0212] The above-described embodiments only express several implementation methods of the present application, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can also be made, which all belong to the protection scope of the present application. In addition, it should be understood that after reading the above-mentioned teaching content of the present application, those skilled in the art can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the protection scope of the present application. It should also be understood that the technical solutions obtained by those skilled in the art on the basis of the technical solutions provided in the present application through logical analysis, reasoning or limited experiments are all within the protection scope of the claims attached to the present application. Therefore, the protection scope of the patent of the present application shall be based on the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof, characterized in that: The pentacyclic triterpenoid compound is selected from the compound of formula (I) or the compound of formula (II); R 1 Selected from hydroxyl or R 2 , R 3 and R 4 are independently selected from: hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C 10 Aryl, substituted or unsubstituted C3~C 10 Heteroaryl, or a suitable combination of C1-C4 alkylene or olefinic bond and the aforementioned groups; The pentacyclic triterpenoid compounds do not include R 1 is selected from hydroxyl and R 2 A compound I-1 selected from hydrogen; 2. The pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: R 1 Selected from R 4 Selected from: hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C 10 Aryl, substituted or unsubstituted C3~C 10 Heteroaryl, or olefinic bond with substituted or unsubstituted C6~C 10 Aromatic combinations.

3. The pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof according to claim 2, characterized in that: R 2 , R 3 and R 4 Each of the following is independently selected from the group consisting of: hydrogen, substituted or unsubstituted C1-C4 alkyl, substituted or unsubstituted C3-C6 cycloalkyl, and substituted or unsubstituted phenyl.

4. The pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: The pentacyclic triterpenoid compound is selected from the compound of formula (I) and the definition of each group is selected from any one of the following groups: (1)R 1 is hydroxyl group, R 2 is ethyl; (2)R 1 for R 4 It is hydroxyl.

5. The pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: The pentacyclic triterpenoid compound is selected from the compound of formula (II), R 3 It is ethyl.

6. The pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 5, characterized in that: The pentacyclic triterpenoid compound is selected from the following structures:

7. A method for preparing a compound of formula (I) according to any one of claims 1 to 6, characterized in that: The steps include: Take a compound of formula (I-1) and a compound R 11 -X1 undergoes esterification reaction to obtain a compound of formula (I-2), The compound of formula (I-2) and the compound Esterification reaction is carried out to obtain a compound of formula (I-3), or Take the compound of formula (I-1) and the compound Carry out esterification reaction to obtain a compound of formula (I-4); Take a compound of formula (I-4) and a compound R 14 -X2 undergoes esterification reaction to obtain a compound of formula (I-5); in, R 12 and R 13 As R 1 Definition of; R 11 and R 14 As R 2 Definition of; X1 and X2 are independently selected from halogen; N1 and N2 are each independently selected from a leaving group.

8. A method for preparing a compound of formula (II) according to any one of claims 1 to 6, characterized in that: The steps include: Take a compound of formula (I-1) and a compound R 15 -X3 undergoes esterification reaction to obtain a compound of formula (I-6), Taking the compound of formula (I-6) and subjecting it to oxidation reaction, oxidizing the hydroxyl group therein to keto group, to prepare the compound of formula (II-1); Among them, R 15 The definition of R 3 ; X3 is selected from halogen.

9. A pharmaceutical composition, characterized in that include: 1) The pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 6; and 2) Pharmaceutically acceptable carrier.

10. Use of the pentacyclic triterpenoid compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 6 in the preparation of a medicament; The drug is selected from: 1) a drug for preventing and / or treating coronavirus infection, and 2) a drug for preventing and / or treating picornavirus infection.

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