PROTAC molecules targeting SARS-CoV-2 3C protease and their applications

Abstract

The present invention relates to a compound represented by formula (I) or a pharmaceutically acceptable salt or solvent compound thereof, wherein M1 represents a 3-chymotrypsin-like protease inhibitor portion; M2 represents an E3 ubiquitin ligase ligand portion; L represents a ligand having ‑(CH2CH2O) q (CH2) e (NH) f (O) g (CH2) h CO(CH2) i (CO) j The present invention also relates to a method for preparing the above-mentioned compound and its use in preparing 3-chymotrypsin-like protease inhibitors and anti-coronavirus drugs. #imgabs0#

Description

Technical Field

[0001] The present application belongs to the field of medicine, and specifically relates to a class of PROTAC (proteolysis targeting chimeras) compounds targeting the 3C protease of the new coronavirus (SARS-CoV-2), or a pharmaceutically acceptable salt or solvate thereof, and also relates to a method for preparing the above-mentioned compound and its use in the preparation of 3-chymotrypsin-like protease inhibitors, especially anti-coronavirus drugs. Background Art

[0002] The pathogenic virus SARS-CoV-2 mainly attacks the lower respiratory system of the human body, causing viral pneumonia; it may also affect the gastrointestinal system, heart, kidneys, liver and central nervous system, seriously threatening human life and health safety, and bringing huge negative impacts to the entire society. As of the submission of this application, the number of global cases and deaths is still rising sharply.

[0003] Judging from the characteristics of the SARS-CoV-2 outbreak in various regions around the world, the virus has a long incubation period, high concealment (asymptomatic transmission, transmission during the incubation period, mild initial symptoms and similar to colds), and strong infectiousness (various transmission routes), which brings great difficulties to prevention and control. Based on the characteristics of the virus, we need to be prepared to coexist with SARS-CoV-2 for a long time. After widespread transmission, the virus may become endemic in the population. Therefore, the research and development of specific drugs for SARS-CoV-2 will be an important direction for the prevention and control of the new coronavirus in the future.

[0004] 3-chymotrypsin-like protease (3C protease), also called the main protease, is a key enzyme in the virus life cycle. It first releases the protease itself by self-cleaving the polyprotein, and then cuts more than 11 sites on the peptide segment to produce various proteins related to replication and transcription. 3C protease plays an important role in regulating the virus life cycle and gene expression. At the same time, it has no obvious homology with human proteins, so it is an important target for the development of anti-coronavirus drugs.

[0005] GC376 (CAS 1416992-39-6) is a covalent inhibitor of SARS-CoV-2 3C protease, which can inhibit the replication of the new coronavirus in vitro. However, it is difficult for GC376 to completely block the replication of the virus and cannot completely inhibit the virus infection process. Moreover, the existing structural modification methods of GC376 usually cannot give GC376 the ability to completely block viral replication. On the contrary, these modification methods may also cause GC376 to be unable to enter the active protein binding domain of 3C protease, unable to interact with its active protein binding domain, and / or change the mechanism of action of GC376 and 3C protease, thereby causing GC376 to lose its ability to bind to 3C protease, unable to effectively inhibit 3C protease, and even more difficult to achieve the purpose of completely blocking viral replication.

[0006] Therefore, there is an urgent need in the prior art for a compound based on GC376, which can not only achieve 3C protease inhibitory activity equivalent to or stronger than GC376, but also completely block the replication of viruses, especially the new coronavirus, and inhibit its infection process. Summary of the invention

[0007] In order to solve the above technical problems, the present invention combines computational chemistry to fully study the mode of action of GC376 and SARS-CoV-2 3C protease, and connects the ligand of E3 ubiquitin ligase through specific connecting arms of different properties at specific sites of GC376 and its series of derivatives to form PROTAC (proteolysis targeting chimeras, protein degradation targeting chimeras) molecules shown in formula (I). The present invention not only retains the binding ability of GC376 with 3C protease by using specific connecting arms and modifying specific groups at specific sites of GC376, but also enables the obtained ternary structure compound to bind to 3C protease and E3 ubiquitin ligase at the same time, and then recruits ubiquitin molecules to the surface of 3C protease through E3 ligase, causing ubiquitination degradation of 3C protein, thereby blocking the replication of the virus through a completely different mechanism of action from GC376, and inhibiting the purpose of its infection process. The present invention finds through cell experiment results that the compounds of the present invention can effectively inhibit the activity of the new coronavirus, and some compounds can even achieve stronger in vitro inhibition of the new coronavirus activity than GC376, EC 50 The lowest concentration can be as low as 0.08 μM. Since the mechanism of action of the compound of the present invention is completely different from that of GC376, the compound of the present invention provides a new and effective way to block the replication and infection of mutant viruses, especially mutant novel coronavirus strains.

[0008] Specifically, the present invention is achieved through the following aspects:

[0009] The first aspect of the present invention provides a compound represented by formula (I) or a pharmaceutically acceptable salt or solvate thereof:

[0010]

[0011] Among them, M 1 represents the 3-chymotrypsin-like protease inhibitor moiety;

[0012] M 2 represents the E3 ubiquitin ligase ligand part;

[0013] L has the structure shown in the following formula:

[0014] -(CH 2 CH 2 O) q (CH 2 ) e (NH) f (O) g (CH 2 ) h CO(CH 2 ) i (CO) j - Type L

[0015] Among them, p is an integer of 0-5; q is an integer of 0-5; e is an integer of 0-6; f is an integer of 0-3; g is an integer of 0-3; h is an integer of 0-3; i is an integer of 0-5; and j is an integer of 0-3.

[0016] The second aspect of the present invention provides a pharmaceutical composition, which comprises: the compound described in the first aspect of the present invention or a pharmaceutically acceptable salt or solvate thereof; and a pharmaceutically acceptable carrier.

[0017] The third aspect of the present invention provides a method for preparing the compound of formula (I), which comprises the following steps: (1) introducing a terminal alkynyl group on a 3-chymotrypsin-like protease inhibitor; (2) introducing an azide group on an E3 ubiquitin ligase ligand; and (3) subjecting the terminal alkynyl group to a click chemistry reaction with the azide group, so that the 3-chymotrypsin-like protease inhibitor is covalently linked to the E3 ubiquitin ligase ligand.

[0018] In the fourth aspect of the present invention, there is provided the use of the compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof in the preparation of 3-chymotrypsin-like protease inhibitors, especially anti-coronavirus drugs. DETAILED DESCRIPTION

[0019] Those skilled in the art will appreciate that the following embodiments are provided for illustrative purposes only and are not intended to limit the scope of protection of the present application in any way.

[0020] In this document, unless otherwise specified, the term "3-chymotrypsin-like protease inhibitor" is used to refer to a compound having 3-chymotrypsin-like protease inhibitory activity. As a non-limiting example, compound GC376 and its derivatives are used as 3-chymotrypsin-like protease inhibitors. In this document, unless otherwise specified, the term "3-chymotrypsin-like protease inhibitor moiety (M 1 )" refers to a structural module obtained by replacing one or more hydrogen atoms on a 3-chymotrypsin-like protease inhibitor with a single bond, and the structural module is covalently linked to other structural modules through the single bond.

[0021] In this document, unless otherwise specified, the term "E3 ubiquitin ligase ligand" or "ligand of E3 ubiquitin ligase" refers to a compound that can bind to E3 ubiquitin ligase. Without wishing to be bound by theory, any E3 ubiquitin ligase ligand in the art can be used in the present invention. As a non-limiting example, the E3 ubiquitin ligase ligand can be a VHL ligand or a CRBN ligand. In this document, unless otherwise specified, the term "E3 ubiquitin ligase ligand moiety (M 2 )” refers to a structural module obtained by replacing one or more hydrogen atoms on the E3 ubiquitin ligase ligand with a single bond, which is covalently linked to other structural modules through the single bond.

[0022] In this article, the term “C m-n " means that the part modified by the term has mn carbon atoms (n is greater than m, and both are integers). For example, C 1-6 It means that the modified part has 1-6 carbon atoms, such as 1 carbon atom, 2 carbon atoms, 3 carbon atoms, 4 carbon atoms, 5 carbon atoms or 6 carbon atoms.

[0023] In this article, unless otherwise indicated, the term "cyclic radical" includes aliphatic cyclic radicals and aromatic cyclic radicals, and refers to a saturated or unsaturated ring system consisting of carbon atoms. The term "heterocyclic radical" includes alicyclic and aromatic heterocyclic rings, and refers to a saturated or unsaturated ring system consisting of carbon atoms and 1-3 heteroatoms independently selected from N, O or S, and can be substituted or unsubstituted. As non-limiting examples of cyclic radicals and heterocyclic radicals, furyl, thienyl, pyridyl, oxazolyl, isoxazolyl, pyrazolyl, phenyl, pyrazinyl, pyrimidinyl, pyridazinyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopentenyl and cyclohexenyl can be listed, but are not limited to this.

[0024] As used herein, the term "triazole moiety" refers to a 1,2,3-triazole moiety. One skilled in the art will appreciate that such triazole moieties are the product of an alkyne / azide reaction cycloaddition reaction performed under "click" chemistry conditions. Protein degradation targeting chimera compounds of the present invention having one or more triazole moieties in their linked structure can be prepared using click chemistry reactions. The term 'click chemistry' was coined in 2001 by Professor K. Barry Sharpless to describe a series of chemical reactions defined by their modular nature, high yield, stability of the product in vivo, stereospecificity, high atom economy, and high thermodynamic driving force. There are many 'click' reactions, several of which involve cycloaddition reactions between appropriate functional groups to produce stable cyclic structures.

[0025] In this article, unless otherwise indicated, the term "pharmaceutically acceptable" used refers to those compounds, materials, compositions and / or dosage forms that are suitable for contact with human and animal tissues without excessive toxicity, irritation, allergic reaction or other problems or complications, and are commensurate with a reasonable benefit / risk ratio, within the scope of reasonable medical judgment. For example, the term "pharmaceutically acceptable salt" used herein refers to an acid addition salt or base addition salt formed by a compound shown in formula (I) and a pharmaceutically acceptable free acid or free base. Acid addition salts are obtained from the following acids: such as hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, nitrous acid, phosphorous acid, acetic acid, benzoic acid, citric acid, lactic acid, maleic acid, gluconic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, tartaric acid, fumaric acid, malic acid, oxalic acid, succinic acid, etc. Base addition salts include sodium salts, potassium salts, calcium salts, ammonium salts, or magnesium salts, etc.

[0026] Unless otherwise specified, solid and dashed keys ( and ) represents the absolute configuration of a stereocenter.

[0027] Unless otherwise stated, stereoisomers referred to herein include geometric isomers and enantiomers, all of which are within the scope of the present application.

[0028] Unless otherwise specified, other terms used herein have the meanings commonly understood by those skilled in the art.

[0029] Implementation of the various aspects described herein may be described by the following numbered paragraphs:

[0030] 1. A compound represented by formula (I) or a pharmaceutically acceptable salt or solvate thereof:

[0031]

[0032] in:

[0033] M 1 represents the 3-chymotrypsin-like protease inhibitor moiety;

[0034] M 2 represents the E3 ubiquitin ligase ligand part;

[0035] L has the structure shown in the following formula:

[0036] -(CH 2 CH 2 O) q (CH 2 ) e (NH) f (O) g (CH 2 ) h CO(CH 2 ) i (CO) j - Type L

[0037] Among them, p is an integer of 0-5; q is an integer of 0-5; e is an integer of 0-6; f is an integer of 0-3; g is an integer of 0-3; h is an integer of 0-3; i is an integer of 0-5; and j is an integer of 0-3.

[0038] The inventors combined computational chemistry to find that by using M 1 and M 2 Through the covalent connection of the connecting arm of the specific length and structure, M 1 Smooth access to the active protein binding domain of 3-chymotrypsin-like protease, thereby ensuring that M 1 and M 2 Binding abilities to 3-chymotrypsin-like protease and E3 ubiquitin ligase, respectively.

[0039] 2. The compound according to paragraph 1 or a pharmaceutically acceptable salt or solvate thereof, wherein the 3-chymotrypsin-like protease inhibitor part M 1 With the following formula (M 1a ) shows the structure:

[0040]

[0041] Among them, R 1 and R 2 Independently selected from the group consisting of H, halogen, hydroxyl, carbonyl, sulfonic acid and carboxyl;

[0042] R 3 Selected from C 1-6 Alkyl, C2-6 Alkenyl and C 2-6 The group consisting of alkynyl groups;

[0043] D 1 and D 2 Independently selected from single bonds, C 1-6 Alkyl, C 2-6 Alkenyl, C 2-6 Alkynyl, -O(CH 2 ) is a group consisting of n-, 3-8 membered cyclic groups or heterocyclic groups, wherein n is an integer selected from 1-5.

[0044] 3. The compound as described in paragraph 2 or a pharmaceutically acceptable salt or solvate thereof, wherein R 1 and R 2 Independently selected from the group consisting of H, hydroxyl, carbonyl and sulfonic acid groups;

[0045] R 3 Selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, tert-butyl, isobutyl, pentyl and hexyl;

[0046] D 1 and D 2 Independently selected from single bonds, O(CH 2 )n, a 3-8 membered cyclic group or a heterocyclic group, wherein n is 1 or 2.

[0047] 4. The compound or pharmaceutically acceptable salt or solvate thereof as described in paragraph 2 or 3, wherein R 1 and R 2 Together with the carbon it is located, it forms any of the following structures: HOCH 2 -、HCO-、 HO(NaO 3 S)CH-、HO(HO 3 S)CH-.

[0048] In this regard, the corresponding structure on the GC376 compound is HO(NaO 3 S)CH-. The present inventors combined computational chemistry and unexpectedly found that the R 1 and R 2 Modified to be independently selected from the group consisting of H, halogen, hydroxyl, carbonyl, sulfonic acid and carboxyl, in particular R 1 and R 2 Together with the carbon it is located, it forms any of the following structures: HOCH 2 -、HCO-、HO(NaO 3 S)CH-、HO(HO 3 S)CH- can achieve 3C protease inhibitory activity similar to or even stronger than that of GC376.

[0049] 5. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 2-4, wherein D 1 and D 2 Independently selected from single bonds, -O(CH 2 )-, furanyl, thienyl, pyridyl, oxazolyl, isoxazolyl, pyrazolyl, phenyl, pyrazinyl, pyrimidinyl, pyridazinyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopentenyl and cyclohexenyl.

[0050] 6. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 2-5, wherein D 1 and D 2 Independently selected from single bonds, -O(CH 2 )-, phenyl and cyclohexyl.

[0051] 7. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 2-6, wherein -D 1 -D 2 - is selected from the group consisting of a single bond, The group composed of.

[0052] 8. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 2-7, wherein -D 1 -D 2 - is selected from the group consisting of a single bond, The group composed of.

[0053] The inventors have found that 1 -D 2 - is a single bond or contains a 3-8 membered cyclic group or heterocyclic group (especially phenyl or cycloalkyl), a stronger 3C protease inhibitory activity can also be achieved. In particular, when the substituent on the 3-8 membered cyclic group or heterocyclic group is in the para position, a significantly stronger 3C protease inhibitory activity can be achieved.

[0054] 9. A compound as described in any one of paragraphs 2-8 or a pharmaceutically acceptable salt or solvate thereof, wherein M 1 With the following formula (M 1b ) shows the structure:

[0055]

[0056] Wherein, each group is as defined in the corresponding paragraph.

[0057] 10. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 1-9, wherein the 3-chymotrypsin-like protease is the 3-chymotrypsin-like protease of the new coronavirus.

[0058] Without wishing to be bound by theory, the 3-chymotrypsin-like protease of the present invention can be the 3-chymotrypsin-like protease of any virus. As a non-limiting example, the 3-chymotrypsin-like protease is the 3-chymotrypsin-like protease of the new coronavirus.

[0059] 11. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 1-10, wherein M 1 Any of the structures shown below:

[0060]

[0061] 12. The compound according to paragraph 11 or a pharmaceutically acceptable salt or solvate thereof, wherein M 1 Any of the structures shown below:

[0062]

[0063]

[0064] 13. The compound or pharmaceutically acceptable salt or solvate thereof according to any one of paragraphs 1 to 12, wherein the E3 ubiquitin ligase ligand is a VHL ligand or a CRBN ligand having the following structure:

[0065]

[0066] 14. The compound according to paragraph 13 or a pharmaceutically acceptable salt or solvate thereof, wherein the E3 ubiquitin ligase ligand portion M 2 Any of the structures shown below:

[0067]

[0068] 15. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 1 to 14, wherein the compound has a structure shown in the following formula (II):

[0069]

[0070] Wherein, each group is as defined in the corresponding paragraph.

[0071] 16. A compound or a pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 1-15, wherein p is an integer of 1-2; q is an integer of 0-3; e is an integer of 2-5; f is an integer of 0-1; g is an integer of 0-1; h is an integer of 0-1; i is an integer of 0-2; and j is an integer of 0-1.

[0072] 17. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 1-16, wherein the total number of carbon atoms in L is selected from integers of 7-9.

[0073] The present inventors have found that controlling the total number of carbon atoms in L to an integer of 7-9 so that L has a specific length helps to ensure that M 1 and M 2 Binding abilities to 3-chymotrypsin-like protease and E3 ubiquitin ligase, respectively.

[0074] 18. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 1-17, wherein L has one of the structures shown below:

[0075] -(CH 2 CH 2 O) 3 (CH 2 ) 2 CO-Formula L 1-1

[0076] -CH 2 CH 2 O(CH 2 ) 2 NHCO(CH 2 ) 2 CO-Formula L 1-2

[0077] -(CH 2 ) 5 OCH 2 CO-Formula L 1-3 .

[0078] 19. The compound or pharmaceutically acceptable salt or solvate thereof according to any one of paragraphs 1 to 18, wherein the compound has a structure shown in the following formula (III) or formula (IV):

[0079]

[0080] Wherein, each group is as defined in the corresponding paragraph.

[0081] 20. The compound or pharmaceutically acceptable salt or solvate thereof according to any one of paragraphs 1 to 19, wherein the compound has a structure as shown in the following formula (V) or formula (VI):

[0082]

[0083] Wherein, each group is as defined in the corresponding paragraph.

[0084] 21. The compound or pharmaceutically acceptable salt or solvate thereof as described in any one of paragraphs 1 to 20, wherein the compound is selected from the group consisting of compounds represented by the following structures:

[0085]

[0086]

[0087]

[0088]

[0089] 22. A pharmaceutical composition comprising: the compound described in any one of paragraphs 1 to 21 or a pharmaceutically acceptable salt or solvate thereof; and a pharmaceutically acceptable carrier.

[0090] 23. A method for preparing the compound described in any one of paragraphs 1 to 21, the method comprising the steps of:

[0091] (1) introducing a terminal alkynyl group on a 3-chymotrypsin-like protease inhibitor;

[0092] (2) introducing an azide group on the E3 ubiquitin ligase ligand; and

[0093] (3) allowing the terminal alkynyl group to undergo a click chemical reaction with the azide group, so that the 3-chymotrypsin-like protease inhibitor is covalently linked to the E3 ubiquitin ligase ligand.

[0094] 24. Use of the compound described in any one of paragraphs 1 to 21 or a pharmaceutically acceptable salt or solvate thereof or the pharmaceutical composition described in paragraph 22 in the preparation of a 3-chymotrypsin-like protease inhibitor.

[0095] 25. Use of the compound described in any one of paragraphs 1 to 21 or its pharmaceutically acceptable salt or solvate or the pharmaceutical composition described in paragraph 22 in the preparation of anti-coronavirus drugs.

[0096] Unless otherwise indicated, the terms "patient," "subject," and "individual" are used interchangeably herein and refer to a human or a non-human animal (eg, primate, rodent, etc.).

[0097] Unless otherwise specified, in this article, the parameter values ​​representing the amount of ingredients or physicochemical properties or reaction conditions, etc. should be understood to be modified by the term "about" in all cases. When the term "about" is used to describe the present invention, the term "about" indicates the error value that exists, for example, it indicates a change within the range of ±10%, such as ±1% of a specific value.

[0098] Unless otherwise stated, herein, singular terms include plural terms and plural terms include singular terms.

[0099] Herein, unless otherwise specified, the terms "comprises, includes and contains" or equivalents are open-ended expressions, meaning that in addition to the listed elements, components and steps, other unspecified elements, components and steps may also be included.

[0100] Example

[0101] Next, the present invention is further described in detail by examples, but the present invention is not limited to these examples. The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents, materials and devices used in the following examples are all commercially available or can be prepared by those skilled in the art according to the common technical knowledge in the art unless otherwise specified.

[0102] Example 1: Preparation of Compounds A, B and C

[0103] Compounds A1, B1 and C1 were synthesized by the following route 1, wherein compound 4 was purchased from Shanghai Shaoyuan Reagent Co., Ltd., and compound 1 and 4-O-propynylbenzyl alcohol were purchased from Aladdin Reagent Co., Ltd.

[0104]

[0105] Preparation Example 1-1: Synthesis of Compounds A1, B1 and C1

[0106] Step 1 Synthesis of intermediate 2: Compound 1 (1.3 g, 7.60 mmol) and 4-O-propynylbenzyl alcohol (0.9 g, 5.55 mmol) were dissolved in dry acetonitrile (30 mL), and 1.5 mL of triethylamine was added. The mixture was reacted at room temperature. After 2 hours, the solution was concentrated and separated by silica gel column. The mobile phase was petroleum ether / ethyl acetate = 4 / 1. 1.75 g of white solid was obtained. The yield was 95%.

[0107] Step 2 Synthesis of intermediate 3: Compound 2 (2.47 g, 7.73 mmol) was dissolved in 30 mL of tetrahydrofuran, and 15 mL of 1 M aqueous LiOH solution was added and stirred at room temperature. After 2 hours, the system was neutralized with an acidic resin to neutrality, the resin was filtered off, and the solution was concentrated. The white solid was directly used for the next reaction.

[0108] Step 3 Synthesis of intermediate 5: Compound 3 (2.1 g, 6.6 mmol) and compound 4 (1.23 g, 6.6 mmol) were dissolved in 30 mL of dry DMF under nitrogen protection, HATU (5.0 g, 13.2 mmol) and DIPEA (1.7 g, 13.2 mmol) were added, and the mixture was reacted at room temperature for 4 hours. DMF was removed by concentration, and the mixture was separated by silica gel column. The mobile phase was petroleum ether / ethyl acetate = 1 / 5, and 2.63 g of white solid product was obtained with a yield of 82%.

[0109] Step 4 Synthesis of Compound A1: Compound 5 (1.5 g, 3.1 mmol) was dissolved in 20 mL dry THF under nitrogen protection, and LiBH was added dropwise. 4 THF solution (2M, 4.8mL), then add 15mL of anhydrous ethanol, and react at room temperature overnight. After the reaction is complete, adjust the pH of the reaction system to 2.0 with 1M hydrochloric acid, extract with ethyl acetate and saturated NaCl solution, dry the organic phase with anhydrous sodium sulfate, filter, concentrate, and separate with a silica gel column. Mobile phase: ethyl acetate / methanol = 20 / 1, and obtain 882mg of white solid product with a yield of 62%.

[0110] Step 5 Synthesis of Compound B1: Compound A1 (400 mg, 0.90 mmol) was dissolved in dry dichloromethane (5 mL) under nitrogen protection, and Dess-Martin Periodinane (DMP) (570 mg, 1.35 mmol) was added under ice-water bath, reacted at room temperature, concentrated after 2 hours, and separated by silica gel column. Mobile phase: ethyl acetate / methanol = 20 / 1, and 288 mg of white solid product was obtained, with a yield of 70%.

[0111] Step 6 Synthesis of Compound C1: Compound B1 (90 mg, 0.197 mmol) was dissolved in ethyl acetate (4 mL) and anhydrous ethanol (2.4 mL), and sodium bisulfite (20 mg, in 185 μL H 2 O), reacted at 50°C. After 3 hours, the reaction solution was cooled to room temperature and filtered. The solid was washed with anhydrous ethanol and dried to obtain a solid, namely compound C1, with a total of 88 mg and a yield of 80%.

[0112] Preparation Example 1-2: Synthesis of Compounds A2, B2 and C2

[0113] Follow Scheme 1 except that 4-O-propynylbenzyl alcohol is replaced by (the compound was purchased from Jiangsu Aikon Biopharmaceutical Research and Development Co., Ltd.), the same steps as the synthesis of compounds A1, B1 and C1 were used to obtain white solid compounds A2, B2 and C2 with yields of 47%, 34% and 29%, respectively.

[0114] Preparation Example 1-3: Synthesis of Compounds A3, B3 and C3

[0115] According to route 1, except that 4-O-propynylbenzyl alcohol was replaced by propynyl alcohol (the compound was purchased from Aladdin Reagent Co., Ltd.), the same steps as the synthesis of compounds A1, B1 and C1 were used to obtain white solid compounds A3, B3 and C3 with yields of 50%, 40% and 32%, respectively. The structures of compounds A2, B2 and C2 and A3, B3 and C3 are shown below:

[0116]

[0117] Example 2: Linking of the tether to the E3 ligase ligand (Compound V)

[0118]

[0119] Compounds V-C7-N3, V-C8-N3 and V-C9-N3 and compounds R-C7-N3, R-C8-N3 and R-C9-N3 were synthesized by the above route 2. Compounds V and R were purchased from Beijing Bailingwei Technology Co., Ltd., linkers 1, 2 and 3 were purchased from Kanglong Chemical (Beijing) New Drug Technology Co., Ltd., and linkers 4, 5 and 6 were prepared from linkers 1, 2 and 3 according to the method of the literature (Synthesis, 2007, 19, 3051-3055).

[0120] Preparation Example 2-1: Synthesis of Compounds V-C7-N3, V-C8-N3 and V-C9-N3

[0121] Compound V (210 mg, 0.49 mmol) and linker arm 1 (120 mg, 0.64 mmol) were dissolved in dry DMF (5 mL), HATU (370 mg, 0.97 mmol) was added, and the mixture was stirred at room temperature for 40 minutes. DIPEA (253 mg, 1.96 mmol) was added, and the reaction was completed after 2 hours at room temperature. The mixture was concentrated and passed through a silica gel column with the mobile phase of ethyl acetate / methanol = 15 / 1 to obtain 235 mg of a white solid with a yield of 80%.

[0122] As shown in Scheme 2, the same steps as those for the synthesis of compound V-C7-N3 were used to obtain white solid compound V-C8-N3 and white solid compound V-C9-N3 in yields of 85% and 82%, respectively.

[0123] Preparation Example 2-2: Synthesis of Compounds R-C7-N3, R-C8-N3 and R-C9-N3

[0124] Compound R (250 mg, 0.92 mmol) and linker 4 (282 mg, 1.37 mmol) were dissolved in dry tetrahydrofuran (5 mL). The solution was refluxed for four hours, then concentrated and separated by silica gel column. The mobile phase was ethyl acetate / methanol = 15 / 1. 317 mg of white solid was obtained. The yield was 78%.

[0125] As shown in Scheme 2, the same steps as those for the synthesis of compound R-C7-N3 were used to obtain white solid compound R-C8-N3 and white solid compound R-C9-N3 in yields of 81% and 80%, respectively.

[0126] Example 3: Modules A / B / C are connected to the ligand of E3 ligase via different linking groups

[0127]

[0128] Preparation Example 3-1: Synthesis of Compound A1-C9-V

[0129] Compound A1 (15 mg, 0.03 mmol) and V-C9-N3 (21 mg, 0.03 mmol) were dissolved in a mixed solvent of methanol (2 mL) and dichloromethane (2 mL), and cuprous chloride (1 mg) was added. The mixture was reacted at room temperature for 3 hours, concentrated, and separated by HPLC. Separation conditions: Angilent C18 column (4 μm, 9.4×250 mm), 10→70% MeCN, 20 min, 2.5 mL / min, UV monitoring at 256 nm. 26 mg of a white foamy solid was obtained, with a yield of 80%.

[0130] Preparation Example 3-2 Synthesis of other target compounds: According to Scheme 3, the same steps as the synthesis of compounds A1-C9-V were used to obtain other target compounds shown in Table 1 using their corresponding raw materials.

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140] Example 4: Application of the compounds of the present invention in anti-SARS-CoV-2

[0141] African green monkey kidney Vero cells were cultured in DMEM (Gibco, USA) medium containing 10% fetal bovine serum (FBS, Gibco, USA), a penicillin concentration of 100 U / ml, and a streptomycin working concentration of 0.1 mg / ml.

[0142] All infection experiments were conducted in a biosafety level 3 (BLS-3) laboratory. 20mM drug was diluted in DMEM (1% double antibody) from 2μM to 0.03125μM, twice. GC376 was used as a positive control, and 0.1% DMSO was used as a blank control. The diluted drug was added to a 96-well plate, 60μL per well. In the 96-well plate with 60μL of drug, 60μL of 200TCID50 / 100μL of the new coronavirus (Nature communications, 2020, 11(1), 1-8) was added, and the final virus concentration was 100TCID50 / 100μL. Incubate the cells at 37°C for 1 hour, wash the plates, add 100 μL of the virus-drug mixture after incubation to each well, set up virus control (only add virus, no drug), set up blank control (no drug, no virus), set up positive control (GC376), observe the cell lesions for 72 hours, calculate the inhibition rate based on the cell lesions, and automatically calculate the EC using Graphpad 50 The results are shown in Table 2 below:

[0143] Table 2 Inhibitory activity of compounds against novel coronavirus

[0144] Compound <![CDATA[EC 50 (μM)]]> Compound <![CDATA[EC 50 (μM)]]> A1-C9-V 0.75 A1-C8-V 0.75 B1-C9-V 0.08 B1-C8-V 0.12 C1-C9-V 0.21 C1-C8-V 0.34 A2-C9-V 1.21 A2-C8-V 1.45 B2-C9-V 0.35 B2-C8-V 1.01 C2-C9-V 0.42 C2-C8-V 1.10 A3-C9-V 1.21 A3-C8-V 12.68 B3-C9-V 0.95 B3-C8-V 10.15 C3-C9-V 1.01 C3-C8-V 10.12 A1-C7-V 0.81 A1-C7-R 0.25 B2-C8-R 0.62 C3-C9-R 2.15 GC376 0.61

[0145] As shown in the results in Table 2, the compounds of the present invention can achieve comparable or stronger novel coronavirus 3C protease inhibitory activity than GC376, and can effectively block the replication and infection process of the novel coronavirus through a mechanism of action that is completely different from GC376.

[0146] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A compound represented by formula (I) or a pharmaceutically acceptable salt thereof: in ： M 1 represents the 3-chymotrypsin-like protease inhibitor moiety; M 1 With the following formula (M 1b ) shows the structure: Among them, R 1 and R 2 Independently selected from the group consisting of H, hydroxyl, carbonyl and sulfonic acid groups; R 3 is isopropyl; D 1 and D 2 Independently selected from -O(CH 2 )-, phenyl and cyclohexyl group; M 2 represents an E3 ubiquitin ligase ligand portion, wherein the E3 ubiquitin ligase ligand portion M 2 Any of the structures shown below: L has one of the following structures: -(CH 2 CH 2 O) 3 (CH 2 ) 2 CO- L 1-1 -CH 2 CH 2 O(CH 2 ) 2 NHCO(CH 2 ) 2 CO- L 1-2 -(CH 2 ) 5 AND 2 CO-L 1-3 ; Here, p is an integer from 1 to 2.

2. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, in, -D 1 -D 2 -Selected from The group composed of.

3. The compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof, in, -D 1 -D 2 -Selected from The group composed of.

4. The compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof, in, M 1 Any of the structures shown below:

5. The compound according to claim 4 or a pharmaceutically acceptable salt thereof, in, M 1 Any of the structures shown below:

6. The compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof, in, The compound has a structure shown in the following formula (II): Wherein, each group is as defined in the corresponding claims.

7. The compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof, in, The compound has a structure shown in the following formula (III) or formula (IV): Wherein, each group is as defined in the corresponding claims.

8. The compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof, in, The compound has a structure shown in the following formula (V) or formula (VI): Wherein, each group is as defined in the corresponding claims.

9. The compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof, in, The compound is selected from the group consisting of compounds having the following structures: 10 . A pharmaceutical composition comprising: the compound according to claim 1 or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable carrier.

11. Use of the compound according to any one of claims 1 to 9 or a pharmaceutically acceptable salt thereof or the pharmaceutical composition according to claim 10 in the preparation of a 3-chymotrypsin-like protease inhibitor.

12. Use of the compound or pharmaceutically acceptable salt thereof according to any one of claims 1 to 9 or the pharmaceutical composition according to claim 10 in the preparation of anti-coronavirus drugs.

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