Aza-bicyclo[3.1.0]hexane derivatives, processes for their preparation and uses thereof

Abstract

The application discloses an azabicyclo[3.1.0]hexane derivative and a preparation method and application thereof, and belongs to the field of biological medicines. The application provides a compound shown in the following formula or a stereoisomer, a geometric isomer, a tautomer, a nitroxide, a hydrate, a solvate, a pharmaceutically acceptable salt or a prodrug thereof; wherein R1 is selected from an alkyl group, an alkylamine group and an alkoxy group, R2 is selected from a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group and a heterocyclic alkyl group, and R3 is selected from -CHO or -CH(OH)SO3Na. The compound has high anti-novel coronavirus activity, can effectively treat and prevent novel coronavirus pneumonia, has the advantage of being orally taken, and provides a new idea for developing orally taken anti-novel coronavirus drugs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of biological medicine, and particularly relates to an azabicyclo[3.1.0]hexane derivative and a preparation method and use thereof. BACKGROUND

[0002] COVID-19 is an acute infectious disease caused by the novel coronavirus SARS-CoV-2. The novel coronavirus gene will produce two overlapping transcription translation products, polyproteins 1a and 1ab, in host cells. After the polyproteins are hydrolyzed by the main protease and papain-like protease, a series of protein monomers with biological functions can be produced, thereby completing the replication and packaging of the virus. Antiviral drugs targeting proteases have achieved great success in the development of HIV and HCV drugs, such as the compounds ritonavir, darunavir and telaprevir. Therefore, the main protease of the novel coronavirus is an ideal target for drug development. Currently, the drugs targeting the main protease of the novel coronavirus are basically injectable drugs, and there is an urgent need to develop orally available anti-novel coronavirus drugs.

[0003] Boceprevir is an HCV protease inhibitor developed by the American Schering-Plough Company (the company merged with Merck in November 2009). On May 13, 2011, the US Food and Drug Administration (FDA) approved the drug for marketing, which is used for the treatment of chronic hepatitis C in certain adult patients. The drug is an oral preparation, and the trade name is Victrelis.

[0004] Previous studies have found that the half inhibitory concentration IC50 of boceprevir for the novel coronavirus protease is 12.43 μM, and the half inhibitory concentration EC50 of boceprevir for the novel coronavirus at the cellular level is 15.57 μM. Boceprevir has the advantage of oral preparation, but the antiviral activity still needs to be further improved.

[0005]

[0006] Based on the current research status, there is an urgent need to develop orally available drugs with high anti-novel coronavirus activity. SUMMARY

[0007] Therefore, the purpose of the present application is to provide an azabicyclo[3.1.0]hexane derivative and a preparation method and use thereof, which has high anti-novel coronavirus activity and is orally available.

[0008] To achieve the above-mentioned purpose of the application, the technical solutions of the present application are as follows:

[0009] In one aspect, the present application provides a compound of Formula (I) or a stereoisomer, geometric isomer, tautomer, nitroso, hydrate, solvate, pharmaceutically acceptable salt, or prodrug thereof:

[0010]

[0011] wherein R1is selected from alkyl, alkylamino, alkoxy, R2is selected from substituted or unsubstituted alkyl, cycloalkyl, aryl, heterocyclylalkyl, and R3is selected from -CHO or -CH(OH)SO3Na.

[0012] Further, R1is selected from C 1-8 alkyl, C 1-8 alkylamino, C 1-8 alkoxy, R2is selected from substituted or unsubstituted C 1-8 alkyl, C 3-5 cycloalkyl, phenyl, oxygen and / or nitrogen containing 5-6 membered heterocyclyl.

[0013] Further, R1is selected from C 1-8 alkylamino, C 1-8 alkoxy, R2is selected from substituted or unsubstituted C 1-8 alkyl.

[0014] Further, R1is selected from C 1-8 alkylamino, C 1-8 alkoxy, R2is selected from substituted or unsubstituted C 1-8 alkyl.

[0015] Further, R1is selected from C 1-6 alkylamino, C 1-6 alkoxy, R2is selected from substituted or unsubstituted C 1-6 alkyl, the substituents are selected from at least one of alkyl, alkoxy, haloalkyl, phenyl, arylheterocyclyl, heterocyclyl.

[0016] Further, R1is selected from C 2-5 alkylamino, C 2-5 alkoxy, R2is selected from substituted or unsubstituted C 1-4 alkyl, the substituents are selected from at least one of alkyl, phenyl, arylheterocyclyl, heterocyclyl.

[0017] Further, R1is selected from C 3-4 alkylamino, C 3-4 alkoxy, R2is selected from substituted or unsubstituted C 1-2 alkyl, the substituents are selected from at least one of alkyl, phenyl.

[0018] Further, R1is selected from C 3-4 alkylamino, C 3-4alkyl. Further, the compound of formula (I) is selected from 1-2 alkyl. Further, the compound of formula (I) is selected from

[0019] Further, the compound of formula (I) is selected from

[0020] Further, the compound of formula (I) is selected from

[0021] The term "alkyl" as used herein, unless otherwise indicated, includes both branched and straight chain saturated aliphatic hydrocarbon groups, including all isomers, having the indicated number of carbon atoms. Commonly used abbreviations for alkyl groups, e.g., methyl, can be represented by "Me" or CH3, ethyl by "Et" or CH2CH3, propyl by "Pr" or CH2CH2CH3, butyl by "Bu" or CH2CH2CH2CH3, and the like. For example, "C 1-4 alkyl" (or "C1-C4alkyl") means a straight or branched chain alkyl group having the indicated number of carbon atoms, including all isomers. C 1-4 alkyl includes n-, i-, s- and t-butyl, n- and i-propyl, ethyl and methyl. The term "C 1-10 alkyl" and the like have similar meanings.

[0022] The term "alkoxy" means a straight chain and branched chain alkyl group of the indicated number of carbon atoms attached through an oxygen bridge.

[0023] The term "halogen" (or "halo") means fluorine, chlorine, bromine and iodine (or fluorinated (F), chlorinated (Cl), brominated (Br) and iodinated (I)).

[0024] The term "aryl" means an aromatic mono- and polycarbocyclic ring system wherein the individual carbocyclic rings are fused or linked by a single bond. Typical aryl groups include phenyl, naphthyl and biphenylene.

[0025] The term "heterocycle" means a ring structure composed of carbon atoms and non-carbon atoms such as nitrogen, oxygen and sulfur. Typical heterocyclic groups include pyridine, quinoline, tropane, phenothiazine, benzodiazepine, furan, pyrazolone and pyrimidine.

[0026] The term "heteroaromatic" refers to a 5- or 6-membered monocyclic aromatic ring or a 7-12 membered bicyclic ring composed of carbon atoms and one or more heteroatoms selected from N, O, and S. Examples of heteroaromatic rings include pyridyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl, thiophenyl (or thienyl), thiazolyl, furanyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, and thiadiazolyl, benzotriazolyl, indolyl, isoindolyl, indazolyl, indolinyl, isoindolinyl, quinoxalinyl, quinazolinyl, cinnolinyl, chromanyl, isochromanyl, tetrahydroquinolinyl, quinolinyl, tetrahydroisoquinolinyl, isoquinolinyl, 2,3-dihydrobenzofuranyl, 2,3-dihydrobenzo-l,4-dioxinyl, imidazo(2,l-b)(l,3)thiazole, and benzo-l,3-dioxolyl.

[0027] Unless expressly stated, all ranges listed herein are inclusive. For example, "n is an integer between 0 and 2" means that n can be 0, 1, or 2.

[0028] The term "pharmaceutically acceptable salt" means a salt prepared from a pharmaceutically acceptable non-toxic base or acid. When the compound of the present application is acidic, its corresponding salt can be readily prepared from an inorganic or organic acid. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, manganous, potassium, sodium, zinc, and the like. Particularly preferred are the ammonium, calcium, magnesium, potassium, and sodium salts. Salts prepared from organic bases include salts of primary, secondary, and tertiary amines, including those derived from natural and synthetic sources. Pharmaceutically acceptable organic non-toxic bases from which salts can be prepared include arginine, betaine, caffeine, choline, N,N'-dibenzylethylene-diamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethyl-morpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, dicyclohexylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine, and the like. When the compound of the present application is basic, its corresponding salt can be readily prepared from an inorganic or organic acid. Such acids include, for example, acetic acid, benzenesulfonic acid, benzoic acid, camphorsulfonic acid, citric acid, ethanesulfonic acid, fumaric acid, gluconic acid, glutamic acid, hydrobromic acid, hydrochloric acid, isethionic acid, lactic acid, maleic acid, malic acid, mandelic acid, methanesulfonic acid, mucic acid, nitric acid, pamoic acid, pantothenic acid, phosphoric acid, succinic acid, sulfuric acid, tartaric acid, p-toluenesulfonic acid, and the like.

[0029] The term "solvate" refers to a complex of variable stoichiometry formed by a solute (i.e., a compound of Formula I) or a pharmaceutically acceptable salt thereof and a solvent, which can be either organic or inorganic. Examples of solvents include, but are not limited to, water, ethanol, and acetic acid. When the solvent is water, the solvate is a hydrate. Hydrates include, but are not limited to, monohydrates, dihydrates, sesqui hydrates, and trihydrates.

[0030] The term "prodrug" is a functional derivative of a compound of the present application that is readily convertible in vivo into the desired compound.

[0031] In another aspect, the present application provides a method for preparing the above-mentioned compound, comprising the following synthetic route:

[0032]

[0033] wherein R1, R2 have the same definition as aforementioned.

[0034] In another aspect, the present application provides a pharmaceutical composition comprising a compound of Formula (I) or a stereoisomer, geometric isomer, tautomer, nitroso, hydrate, solvate, pharmaceutically acceptable salt or prodrug thereof, and one or more pharmaceutically acceptable carriers, diluents, excipients.

[0035] In the pharmaceutical composition, the term "composition" includes a product comprising the active ingredient and the inert ingredient (pharmaceutically acceptable excipient) constituting the carrier, and any product directly or indirectly obtained by combination, complexation or aggregation of two or more ingredients, or by decomposition of one or more ingredients, or by other types of reactions or interactions of one or more ingredients. Accordingly, the pharmaceutical composition of the present application includes any composition prepared by mixing a compound of Formula I, other active ingredients, and pharmaceutically acceptable excipients.

[0036] The active ingredient can be administered orally in solid dosage forms, such as capsules, tablets, troches, lozenges, granules, and powders, or in liquid dosage forms, such as elixirs, syrups, emulsions, dispersions, and suspensions.

[0037] When the compound of the present application is administered in combination with other therapeutic agents, the same dosage forms as aforementioned can be used. When the drugs are administered in physical combination, the dosage form and the route of administration should be selected according to the compatibility of the combined drugs. The compound of the present application can be administered as the sole active ingredient or in combination with a second active ingredient, which includes an active ingredient known to be useful for increasing the level of erythropoietin in a patient.

[0038] Finally, the present application provides a use of the compound represented by formula (I) or its stereoisomer, geometric isomer, tautomer, nitroxide, hydrate, solvate, pharmaceutically acceptable salt or prodrug thereof, or the above pharmaceutical composition in the preparation of a drug for treating acute infectious diseases caused by SARS-CoV-2.

[0039] The beneficial effects of the present application are:

[0040] A new compound is proposed, which has high anti-SARS-CoV-2 activity and can effectively treat and prevent acute infectious diseases caused by SARS-CoV-2 or related conditions. At the same time, it has the advantage of being orally available, providing a new idea for the development of orally available anti-SARS drugs. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 Compound B prepared for the example and the complex crystal structure of the main protease of the new type of virus;

[0042] Figure 2 Compound A prepared for the example and the complex crystal structure of the main protease of the new type of coronavirus;

[0043] Figure 3 Characterization spectrum of compound A;

[0044] Figure 4 Characterization spectrum of compound B;

[0045] Figure 5 Characterization spectrum of compound C;

[0046] Figure 6 Characterization spectrum of compound D;

[0047] Figure 7 Characterization spectrum of compound E. DETAILED DESCRIPTION

[0048] The following non-limiting examples can enable those of ordinary skill in the art to more fully understand the present application, but in no way limit the present application. The following content is only an exemplary description of the scope of the present application, and those skilled in the art can make various changes and modifications to the application disclosed herein, which should also belong to the scope of the present application.

[0049] The present application will be further described in the following specific examples. The various chemical reagents used in the examples of the present application are obtained by conventional commercial routes unless otherwise specified.

[0050] Example 1 Synthesis of compound A

[0051] Test method:

[0052]

[0053] In a 100 mL round-bottom flask, compound 1 (230 mg, 1.0 mmol), compound 2 (169 mg, 1.0 mmol), HOBT (202 mg, 1.5 mmol) were added, then dichloromethane 50 mL was added, the reaction solution was stirred in ice water bath for 30 minutes. Then DIPEA (348 μL, 2 mmol) was added. EDCI (288 mg, 1.5 mmol) was weighed and dissolved in 10 mL of dichloromethane, and added to the reaction solution with a dropping funnel. After the addition was completed, the ice water bath was removed, and the reaction solution continued to react at room temperature for 18 hours. After the reaction was completed, 30 mL of distilled water was added to the round-bottom flask, and stirred for 10 minutes. The liquid was transferred to a separatory funnel, and the lower organic phase was collected, then the organic phase was washed with 1M HCl and saturated NaCl solution, and the organic phase was dried with anhydrous Na2SO4. After drying for 30 minutes, it was filtered and rotary evaporated. Purified by flash liquid chromatography, eluted with a gradient of 0-100% n-hexane: ethyl acetate, and the target product was collected by spotting, and rotary evaporated to obtain 368 mg of white solid compound 3 with a yield of 96%. 1 H NMR (500 MHz, Methanol-d4) δ 4.24 (s, 1H), 4.18 (s, 1H), 3.97 (d, J = 10.4 Hz, 1H), 3.79 (dd, J = 10.4, 5.4 Hz, 1H), 3.63 (s, 3H), 1.45 (dd, J = 7.5, 5.3 Hz, 1H), 1.36 (d, J = 7.6 Hz, 1H), 1.16 (s, 9H), 0.93 (d, J = 26.7 Hz, 11H), 0.82 (d, J = 2.9 Hz, 3H).

[0054] In a 100 mL round-bottom flask, compound 3 (381 mg, 1.0 mmol) was added, then tetrahydrofuran 10 mL, methanol 10 mL were added, and the reaction solution was stirred in an ice water bath for 30 minutes. Then 1M LiOH solution (3 mL, 3 mmol) was added dropwise to the reaction solution. After the addition was completed, the ice water bath was removed, and the reaction solution continued to react at room temperature for 18 hours. After the reaction was completed, 30 mL of distilled water was added to the round-bottom flask, then 1M hydrochloric acid solution was added to adjust the pH value to 3, 50 mL of ethyl acetate was added to the round-bottom flask, and stirred for 10 minutes. The liquid was transferred to a separatory funnel, and the upper organic phase was collected, then the aqueous phase was extracted with 50 mL of ethyl acetate twice, and the organic phase was combined and dried with anhydrous Na2SO4. After drying for 30 minutes, it was filtered and rotary evaporated to obtain 330 mg of white solid compound 4 with a yield of 90%.

[0055] In a 25 mL round bottom flask, compound 5 (286 mg, 1.0 mmol) was added, followed by trifluoroacetic acid 4 mL and dichloromethane 4 mL, stirred at room temperature for 3 hours, and concentrated by rotary evaporation to obtain compound 6.

[0056] In a 100 mL round bottom flask, compound 4 (367 mg, 1.0 mmol), compound 6 (186 mg, 1.0 mmol), HATU (418 mg, 1.1 mmol) were added, followed by N,N-dimethylformamide 20 mL, and the reaction solution was stirred in an ice water bath for 30 minutes. Then DIPEA (550 μL, 3 mmol) was added dropwise to the reaction solution, and after the dropwise addition was completed, the ice water bath was removed, and the reaction solution was continued to react at room temperature for 18 hours. After the reaction was completed, 30 mL of distilled water and 50 mL of water were added to the round bottom flask, and stirred for 10 minutes. The liquid was transferred to a separatory funnel, and the upper organic phase was collected, and then the organic phase was washed with 1M HCl and saturated NaCl solution, and the organic phase was dried with anhydrous Na2SO4. After drying for 30 minutes, it was filtered and rotary evaporated. Purified by flash liquid chromatography, eluted with a gradient of 0-10% dichloromethane:methanol, and the target product was collected by spotting, and rotary evaporated to obtain 417 mg of white solid compound 7, with a yield of 78%.

[0057] 1 H NMR (500 MHz, Methanol-d4) δ 4.46 (dd, J = 12.1, 3.8 Hz, 1H), 4.19 (d, J = 29.4 Hz, 2H), 3.94 (d, J = 10.3 Hz, 1H), 3.85 (dd, J = 10.2, 5.5 Hz, 1H), 3.64 (s, 3H), 3.19 - 3.12 (m, 1H), 2.56 (tdd, J = 10.6, 8.4, 3.8 Hz, 1H), 2.23 (dddd, J = 15.1, 8.8, 6.9, 2.2 Hz, 1H), 2.11 - 2.01 (m, 1H), 1.74 - 1.64 (m, 2H), 1.47 (dd, J = 7.7, 5.2 Hz, 1H), 1.34 (d, J = 7.7 Hz, 1H), 1.24 - 1.17 (m, 4H), 1.16 (s, 10H), 0.97 (s, 3H), 0.89 (s, 9H), 0.85 (s, 3H).

[0058] In a 100 mL round bottom flask, compound 7 (535 mg, 1.0 mmol) was added, followed by the addition of 10 mL of anhydrous methanol. The reaction was stirred in an ice water bath for 30 minutes. Then, sodium borohydride powder (296 mg, 8 mmol) was added to the reaction. After the addition was complete, the ice water bath was removed and the reaction was allowed to continue at room temperature for 3 hours. After the reaction was complete, 30 mL of distilled water was added to the round bottom flask, followed by the addition of 50 mL of dichloromethane. The liquid was transferred to a separatory funnel and the lower organic phase was collected. The organic phase was washed with saturated NaCl solution and dried over anhydrous Na2S04. After drying for 30 minutes, the mixture was filtered and concentrated to yield 405 mg of white solid compound 8, with a yield of 80%.

[0059] 1 H NMR (500 MHz, Methanol-d4) δ 7.32-7.26 (m, 4H), 7.25-7.21 (m, 1H), 4.49 (dd, J = 9.4, 4.8 Hz, 1H), 4.31 (s, 1H), 4.02 (dtd, J = 11.7, 5.6, 3.4 Hz, 1H), 3.91 (d, J = 3.1 Hz, 2H), 3.56 (d, J = 5.5 Hz, 2H), 3.31-3.28 (m, 1H), 3.08 (dd, J = 14.1, 4.7 Hz, 1H), 2.74 (dd, J = 14.1, 9.4 Hz, 1H), 2.69-2.61 (m, 1H), 2.42-2.33 (m, 1H), 1.98 (ddd, J = 13.9, 11.9, 3.8 Hz, 1H), 1.78 (dq, J = 12.4, 9.1 Hz, 1H), 1.61-1.53 (m, 2H), 1.50 (s, 1H), 1.35 (s, 9H), 1.32 (s, 1H), 1.27 (s, 1H), 1.09 (s, 3H), 1.00 (s, 3H).

[0060] In a 100 mL round bottom flask, compound 8 (507 mg, 1.0 mmol) was added, followed by the addition of 20 mL of dichloromethane. Then, Dess-Martin reagent powder (848 mg, 2 mmol) was added to the reaction. The reaction was allowed to continue at room temperature for 3 hours. After the reaction was complete, the mixture was filtered and concentrated, and then purified using a flash liquid chromatograph with a gradient elution of 0-10% dichloromethane:methanol. The target product was collected on a plate and concentrated to yield 414 mg of white solid compound A, with a yield of 82%.

[0061] 1H NMR (500 MHz, DMSO-d6) δ 9.45 (s, 1H), 8.57 (d, J = 7.7 Hz, 1H), 7.64 (s, 1H), 7.29 - 7.25 (m, 4H), 7.19 (s, 1H), 4.25 (d, J = 16.3 Hz, 2H), 4.18 (ddd, J = 11.6, 7.7, 3.9 Hz, 1H), 3.91 - 3.77 (m, J = 6.9, 6.0 Hz, 2H), 3.18 - 3.06 (m, 2H), 2.89 (dd, J = 14.0, 4.0 Hz, 1H), 2.69 (dd, J = 14.0, 10.1 Hz, 1H), 2.43 - 2.34 (m, 1H), 2.20 - 2.12 (m, 1H), 1.94 - 1.86 (m, 1H), 1.66 - 1.58 (m, 2H), 1.54 (dd, J = 7.8, 4.5 Hz, 1H), 1.38 (d, J = 7.6 Hz, 1H), 1.28 (s, 9H), 1.22 (s, 2H), 1.04 (s, 3H), 0.92 (s, 3H). Synthesis of compound B of Example 2

[0062] Test method:

[0063]

[0064] In a 100 mL round bottom flask was added compound 9 (230 mg, 1.0 mmol), compound 2 (169 mg, 1.0 mmol), HOBT (202 mg, 1.5 mmol), then added dichloromethane 50 mL, the reaction liquid was stirred in ice water bath for 30 minutes. Then added DIPEA (348 μL, 2 mmol). Weighed EDCI (288 mg, 1.5 mmol) was dissolved in 10 ml dichloromethane, added to the reaction liquid with a dropping funnel. After the addition was completed, the ice water bath was removed, and the reaction liquid continued to react at room temperature for 18 hours. After the reaction was completed, 30 mL of distilled water was added to the round bottom flask, and stirred for 10 minutes. The liquid was transferred to a separatory funnel, and the lower organic phase was collected, then the organic phase was washed with 1M HCl and saturated NaCl solution, and the organic phase was dried with anhydrous Na2SO4. After drying for 30 minutes, it was filtered and rotary evaporated. Purified by flash liquid chromatography, eluted with a gradient of 0-100% n-hexane: ethyl acetate, collected the target product by spotting plate, and rotary evaporated to obtain 358 mg of white solid compound 10 with a yield of 86%. 1H NMR (500 MHz, Methanol-d4) δ 7.22 - 7.06 (m, 6H), 4.39 (dd, J = 8.3, 6.2 Hz, 1H), 4.22 (s, 1H), 3.82 (d, J = 10.3 Hz, 1H), 3.67 (s, 1H), 3.61 (s, 3H), 3.54 (dd, J = 10.4, 5.4 Hz, 1H), 2.92 (dd, J = 13.9, 6.2 Hz, 1H), 2.68 (dd, J = 13.9, 8.3 Hz, 1H), 1.42 (dd, J = 7.5, 5.3 Hz, 1H), 1.34 (d, J = 7.4 Hz, 1H), 1.29 (s, 2H), 1.25 (s, 9H), 1.19 (s, 2H), 0.95 (s, 3H), 0.87 (s, 3H).

[0065] In a 100 mL round bottom flask, compound 10 (416 mg, 1.0 mmol) was added, then tetrahydrofuran 10 mL, methanol 10 mL, the reaction solution was stirred in ice water bath for 30 minutes. Then 1 M LiOH solution (3 mL, 3 mmol) was added dropwise to the reaction solution. After the dropwise addition was completed, the ice water bath was removed, and the reaction solution was continued to react at room temperature for 18 hours. After the reaction was completed, 30 mL of distilled water was added to the round bottom flask, then 1 M hydrochloric acid solution was added to adjust the pH value to 3, 50 mL of ethyl acetate was added to the round bottom flask, and stirred for 10 minutes. The liquid was transferred to a separatory funnel, and the upper organic phase was collected, then the aqueous phase was extracted with 50 mL of ethyl acetate twice, and the organic phase was combined and dried with anhydrous Na2SO4. After drying for 30 minutes, filtration and rotary evaporation gave 382 mg of white solid compound 11 with a yield of 95%.

[0066] In a 25 mL round bottom flask, compound 5 (286 mg, 1.0 mmol) was added, then trifluoroacetic acid 4 mL and dichloromethane 4 mL were added, stirred at room temperature for 3 hours, and concentrated by rotary evaporation to give compound 6.

[0067] In a 100 mL round bottom flask was added compound 11 (402 mg, 1.0 mmol), compound 6 (186 mg, 1.0 mmol), HATU (418 mg, 1.1 mmol), then added N,N- dimethylformamide 20 mL, the reaction was stirred in ice water bath for 30 minutes. Then DIPEA (550 μL, 3 mmol) was added dropwise to the reaction, after the dropwise addition was completed, the ice water bath was removed, and the reaction was continued to react at room temperature for 18 hours. After the reaction was completed, 30 mL distilled water and 50 mL water were added to the round bottom flask, and stirred for 10 minutes. The liquid was transferred to a separatory funnel, the upper organic phase was collected, then the organic phase was washed with 1 M HC1 and saturated NaCl solution, and the organic phase was dried with anhydrous Na2S04. After drying for 30 minutes, it was filtered and rotary evaporated. Purified by flash liquid chromatography, eluted with a gradient of 0-10% dichloromethane:methanol, and the target product was collected by spotting on a plate and rotary evaporated to give 399 mg of white solid compound 12, with a yield of 70%.

[0068] 1 H NMR (500 MHz, Methanol-d4) δ 7.21 - 7.06 (m, 6 H), 4.45 (dd, J = 11.8, 3.9 Hz, 1 H), 4.37 (dd, J = 9.4, 4.8 Hz, 1 H), 4.25 (s, 1 H), 3.83 - 3.74 (m, 2 H), 3.64 (s, 3 H), 3.60 (s, 1 H), 3.23 (d, J = 2.4 Hz, 1 H), 2.95 (dd, J = 14.1, 4.6 Hz, 1 H), 2.62 (ddd, J = 12.6, 8.9, 3.8 Hz, 1 H), 2.59 - 2.50 (m, 1 H), 2.24 (dddd, J = 12.0, 8.8, 6.2, 3.0 Hz, 1 H), 2.12 - 2.02 (m, 1 H), 1.79 - 1.65 (m, 2 H), 1.48 (dd, J = 7.7, 4.9 Hz, 1 H), 1.39 (d, J = 7.6 Hz, 1 H), 1.23 (s, 9 H), 1.16 (s, 1 H), 0.99 (s, 3 H), 0.95 (s, 1 H), 0.90 (s, 3 H).

[0069] In a 100 mL round bottom flask, compound 12 (570 mg, 1.0 mmol) was added, followed by the addition of 10 mL of anhydrous methanol. The reaction was stirred in an ice water bath for 30 minutes. Then, sodium borohydride powder (296 mg, 8 mmol) was added to the reaction. After the addition was complete, the ice water bath was removed and the reaction was allowed to continue at room temperature for 3 hours. After the reaction was complete, 30 mL of distilled water was added to the round bottom flask, followed by the addition of 50 mL of dichloromethane. The liquid was transferred to a separatory funnel and the lower organic phase was collected. The organic phase was washed with saturated NaCl solution and dried over anhydrous Na2S04. After drying for 30 minutes, the mixture was filtered and concentrated to yield 461 mg of white solid compound 13, with a yield of 80%.

[0070] 1 H NMR (500 MHz, Methanol-d4) δ 7.21 - 7.06 (m, 6H), 4.45 (dd, J = 11.8, 3.9 Hz, 1H), 4.37 (dd, J = 9.4, 4.8 Hz, 1H), 4.25 (s, 1H), 3.83 - 3.74 (m, 2H), 3.64 (s, 3H), 3.60 (s, 1H), 3.23 (d, J = 2.4 Hz, 1H), 2.95 (dd, J = 14.1, 4.6 Hz, 1H), 2.62 (ddd, J = 12.6, 8.9, 3.8 Hz, 1H), 2.59 - 2.50 (m, 1H), 2.24 (dddd, J = 12.0, 8.8, 6.2, 3.0 Hz, 1H), 2.12 - 2.02 (m, 1H), 1.79 - 1.65 (m, 2H), 1.48 (dd, J = 7.7, 4.9 Hz, 1H), 1.39 (d, J = 7.6 Hz, 1H), 1.23 (s, 9H), 1.16 (s, 1H), 0.99 (s, 3H), 0.95 (s, 1H), 0.90 (s, 3H).

[0071] In a 100 mL round bottom flask, compound 13 (542 mg, 1.0 mmol) was added, followed by the addition of 20 mL of dichloromethane. Then, Dess-Martin reagent powder (848 mg, 2 mmol) was added to the reaction. The reaction was allowed to continue at room temperature for 3 hours. After the reaction was complete, the mixture was filtered and concentrated. The mixture was purified using a flash liquid chromatograph with a gradient elution of 0-10% dichloromethane:methanol. The target product was collected on a plate and concentrated to yield 410 mg of white solid compound B, with a yield of 76%.

[0072] 11H NMR (500 MHz, Methanol-d4) δ 7.21 - 7.06 (m, 6H), 4.45 (dd, J = 11.8, 3.9 Hz, 1H), 4.37 (dd, J = 9.4, 4.8 Hz, 1H), 4.25 (s, 1H), 3.83 - 3.74 (m, 2H), 3.64 (s, 3H), 3.60 (s, 1H), 3.23 (d, J = 2.4 Hz, 1H), 2.95 (dd, J = 14.1, 4.6 Hz, 1H), 2.62 (ddd, J = 12.6, 8.9, 3.8 Hz, 1H), 2.59 - 2.50 (m, 1H), 2.24 (dddd, J = 12.0, 8.8, 6.2, 3.0 Hz, 1H), 2.12 - 2.02 (m, 1H), 1.79 - 1.65 (m, 2H), 1.48 (dd, J = 7.7, 4.9 Hz, 1H), 1.39 (d, J = 7.6 Hz, 1H), 1.23 (s, 9H), 1.16 (s, 1H), 0.99 (s, 3H), 0.95 (s, 1H), 0.90 (s, 3H).

[0073] Synthesis of compound C of example 3

[0074] The synthesis of compound C was performed as for compounds A and B, only the structure of the starting material was changed to obtain the corresponding structure of compound C. The final yield was 42%.

[0075] 1H NMR (500 MHz, DMSO-d6) δ 9.45 (s, 1H), 8.57 (d, J = 7.7 Hz, 1H), 7.64 (s, 1H), 7.29 - 7.25 (m, 4H), 7.19 (s, 1H), 4.25 (d, J = 16.3 Hz, 2H), 4.18 (ddd, J = 11.6, 7.7, 3.9 Hz, 1H), 3.91 - 3.77 (m, J = 6.9, 6.0 Hz, 2H), 3.18 - 3.06 (m, 2H), 2.89 (dd, J = 14.0, 4.0 Hz, 1H), 2.69 (dd, J = 14.0, 10.1 Hz, 1H), 2.43 - 2.34 (m, 1H), 2.20 - 2.12 (m, 1H), 1.94 - 1.86 (m, 1H), 1.66 - 1.58 (m, 2H), 1.54 (dd, J = 7.8, 4.5 Hz, 1H), 1.38 (d, J = 7.6 Hz, 1H), 1.28 (s, 9H), 1.22 (s, 2H), 1.04 (s, 3H), 0.92 (s, 3H).

[0076] Synthesis of compound D of example 4

[0077] In a 100 mL round bottom flask, compound A (505 mg, 1.0 mmol), sodium bisulfite (124 mg, 1.2 mmol) were added. Then 4 mL ethyl acetate, 2 mL ethanol and 0.8 mL water were added to the round bottom flask. The reaction was carried out at 40 °C for 3 hours. After the reaction was completed, the reaction mixture was filtered and concentrated to get a light yellow oily liquid. Then 10 mL ethyl acetate was added, and white solid D was obtained after filtration with a yield of 68%.

[0078] Example 5 Synthesis of compound E

[0079] In a 100 mL round bottom flask, compound C (539 mg, 1.0 mmol), sodium bisulfite (124 mg, 1.2 mmol) were added. Then 4 mL ethyl acetate, 2 mL ethanol and 0.8 mL water were added to the round bottom flask. The reaction was carried out at 40 °C for 3 hours. After the reaction was completed, the reaction mixture was filtered and concentrated to get a light yellow oily liquid. Then 10 mL ethyl acetate was added, and white solid E was obtained after filtration with a yield of 72%.

[0080] Table 1. Characterization parameters of compounds A-E

[0081]

[0082]

[0083]

[0084] Results detection

[0085] 1. Evaluation of compounds on proteasome inhibitory activity

[0086] Test method:

[0087] The 10 mM bortezomib, compound A-E solutions were diluted with PBS solution to 100 μM, 20 μM, 4 μM, 0.8 μM, 0.16 μM, 0.032 μM, 0.0064 μM, 0.00128 μM solutions, respectively.

[0088] Add 10 μL of different concentrations of compound solution to a black 96-well plate, 3 holes for each concentration, and then add 30 μL of 3 μM new coronavirus main protease solution. At the same time, set up the control group: the negative control group is to add 10 μL of PBS solution and 30 μL of 3 μM new coronavirus main protease solution, and repeat 3 holes; the blank control group is to add 40 μL of PBS buffer solution, and repeat 3 holes. Then put the black 96-well plate into a 37-degree incubator for 30 minutes. Then add 10 μL of 20 μM substrate (DABCYL-TSAVLQSGFRKME-EDANS) solution to each hole, and immediately measure the fluorescence value (Ex 340nM, Em 490nM) per minute for 60 minutes with an enzyme marker. Each hole is measured for 61 times.

[0089] Draw the protease reaction curve graph with time as the horizontal coordinate and fluorescence value as the vertical coordinate using GraphPad Prism software, and calculate the enzyme reaction rate V in 30 minutes. The enzyme reaction rate of the negative control is V max , the enzyme reaction rate after adding different concentrations of compounds is V x , and the fluorescence change rate of the blank control is V0. Then the inhibition rate of different concentrations of compounds on the enzyme reaction activity is 1-(V x -V0) / (V max -V0)×100%. Then use GraphPad Prism analysis to get the IC 50 value of the compound on the main protease after plotting.

[0090] 2. Inhibition effect of compounds on new coronavirus at cell level

[0091] Test method:

[0092] Dilute 10 mM of boscalid, compound A-E solutions with PBS solution to 200 μM, 40 μM, 8 μM, 1.6 μM, 0.32 μM, 0.064 μM, 0.0128 μM, 0.00256 μM solutions with DMEM medium respectively. Dilute 100% DMSO to 1% DMSO medium solution as a blank control.

[0093] Dilute SARS-Cov-2 virus to 0.01 MOI with DMEM in a biological safety cabinet. Take the 96-well plate full of Vero cells to the biological safety cabinet. Add 100 μL of 0.01 MOI virus solution to each well of the 96-well plate, and add 100 μL of DMEM to 3 wells (as uninfected group), and put into a CO2 incubator for 2 h. In the biological safety cabinet, aspirate the virus supernatant and wash with PBS, and then add 100 μL of different compound medium solution and 100 μL of 1% DMSO medium solution to different wells. At the same time, add 1% DMSO medium solution to the uninfected group and the drug-free group. Each concentration gradient is repeated 3 times. Take the cell culture plate out of the biological safety cabinet and put it into a CO2 incubator for incubation at 37°C with 5% CO2. After 48 h, lyse the cells, extract RNA, and perform RT-PCR to detect the Ct value.

[0094] The results are shown in Table 2.

[0095] Table 2.

[0096]

[0097] It can be seen that the compound provided by the present application has high anti-SARS-CoV-2 activity, and as an oral drug, it is significantly higher than the existing drug remdesivir.

[0098] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A compound of formula (I) or a pharmaceutically acceptable salt thereof; wherein R2 is tert-butyl, R3 is -CH(OH)SO3Na; R2 is benzyl, R3 is selected from -CHO or -CH(OH)SO3Na. wherein R1is selected from C 2-5 alkyl, C 2-5 alkoxy; 2. The compound or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that, The following synthetic routes are used: wherein R1, R2 have the same definition as in any one of claims 1-3. The compound of formula (I) is selected from 3. The compound of claim 2, or a pharmaceutically acceptable salt thereof, wherein, The compound of formula (I) is selected from 4. Process for the preparation of a compound according to any one of claims 1 to 3, characterized in that, A pharmaceutical composition comprising a compound or a pharmaceutically acceptable salt thereof according to any one of claims 1-3, and one or more pharmaceutically acceptable carriers, diluents, excipients.

6. Use of a compound or a pharmaceutically acceptable salt thereof according to any one of claims 1-3, or a pharmaceutical composition according to claim 5, in the manufacture of a medicament for the treatment of acute infectious disease caused by SARS-CoV-2.

5. A pharmaceutical composition, characterized by, ​ ​

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