Thiophene-2-carboxylic acid derivative, and preparation method therefor and medical use thereof

Abstract

Provided are a thiophene-2-carboxylic acid derivative, and a preparation method therefor and the medical use thereof. Also provided are a thiophene-2-carboxylic acid derivative as represented by general formula (I), and an enantiomer, diastereoisomer, tautomer, N-oxide, solvate, physiologically hydrolysable ester, preparation and pharmaceutically acceptable salt thereof. Further provided are a thiophene-2-carboxylic acid derivative having an inhibitory effect on a P2Y14 receptor and a pharmaceutically acceptable salt thereof. Pharmacological experiments show that the compound has a significant inhibitory effect on the P2Y14 receptor, and can be particularly used as a drug for treating inflammatory diseases.

Description

Thiophene-2-carboxylic acid derivatives, preparation methods and medical uses thereof Technical Field

[0001] The present invention relates to a compound, a preparation method and an application thereof, and in particular to a thiophene-2-carboxylic acid derivative, a preparation method and a medical application thereof. Background Art

[0002] When the body is stressed or injured, various important intracellular molecules, such as adenosine-5'-triphosphate (ATP) and uridine-5'-triphosphate (UTP), are released into the extracellular fluid by specific tissues or organs. These nucleotides have the ability to regulate innate and adaptive immune responses by binding to cell surface receptors. The bound receptors are identified as purinergic receptors, which are mainly divided into adenosine (P1) and nucleotide (P2) receptors. The P2 family is further divided into two subfamilies, P2X receptors and P2Y receptors (P2YRs). P2YRs belong to the family of G protein-coupled receptors (GPCRs), which are composed of P2Y1-like receptors (P2Y 1,2,4,6,11 ) and P2Y12-like (P2Y 12,13,14 ). The reported P2Y receptor family of G protein-coupled receptors includes 8 subtypes (P2Y 1、2、4、6、11、12、13、14 ), widely distributed in various cells and tissues, and the homology between each subtype is relatively low, so different subtypes have high selectivity for ligands. 1、2、4、6 Receptor-binding G q and activate the PLC pathway; P2Y 12、13、14 Receptor-binding G i Inhibits adenylate cyclase activity; P2Y4 receptor-coupled G q / G i Two G proteins; P2Y 11 Coupling G q / G s Two G proteins. P2Y receptors mediate a series of biological effects such as immune regulation, platelet aggregation, and smooth muscle cell proliferation.

[0003] P2Y 14 The receptor is activated by at least four naturally occurring UDP sugars, particularly UDP glucose (UDPG). 14 The receptor has been found to be widely expressed in a range of human tissues, including the brain, heart, adipose tissue, placenta, intestine, and hematopoietic stem cells. 14 The receptor activates the G i Protein, inhibiting adenylate cyclase (AC), reducing the production of 3',5' cyclic adenosine monophosphate (cAMP) in cells and the corresponding biological effects.

[0004] P2Y 14The receptor has been shown to be a potential target for innate immune inflammatory diseases such as diabetes, cystic fibrosis, sterile renal inflammation, acute gouty arthritis and allergic diseases. 14 The receptor promotes the recruitment and chemotaxis of neutrophils and macrophages, releasing pro-inflammatory cytokines, chemokines and mast cell mediators. In severe cases of COVID-19, a large part of the severe course is caused by systemic inflammation, known as "cytokine storm". 14 The role of receptors on neutrophils and the high levels of UDPG found in patients with severe COVID-19, a 14 The mechanism by which receptor antagonists prevent uncontrolled neutrophil chemotaxis has been proposed to avoid cytokine storm and systemic inflammation, thereby reducing patient mortality. 14 Knockout of the receptor gene inhibits macrophage recruitment and tissue inflammation, alleviating high-fat diet-induced insulin resistance. Another study showed that glycogen metabolism also increases the level of UDPG and P2Y in macrophages. 14 Blocking this glycogen metabolism pathway can effectively inhibit lipopolysaccharide (LPS)-induced acute peritonitis. 14 The receptor may be a potential therapeutic target for innate immune system diseases.

[0005] Currently, P2Y 14 The research on receptor antagonists has only reported compounds of four structural types (pyrimidopyridines, 2-naphthoic acids, 3-substituted benzoic acids and pyrazole-3-carboxylates), but they are still in the preclinical research stage. Among them, 2-naphthoic acids have the highest activity and selectivity. However, the antagonists of 2-naphthoic acid structure reported so far have defects such as poor solubility, low oral bioavailability, and difficulty in synthesis and purification, which have brought great difficulties to further discussion of structure-activity relationship and biological evaluation. Therefore, it is necessary to find new structural types of P2Y 14 Receptor antagonist, improves the poor drugability of 2-naphthoic acid antagonists, and becomes the discovery of P2Y 14 A new strategy for receptor antagonists.

[0006] Summary of the Invention

[0007] Purpose of the invention: The purpose of the present invention is to provide a novel structure with P2Y 14 Thiophene-2-carboxylic acid derivatives and pharmaceutically acceptable salts thereof having receptor antagonistic effects. Another object of the present invention is to provide a method for preparing the aforementioned thiophene-2-carboxylic acid derivatives. Still another object of the present invention is to provide a use of the aforementioned thiophene-2-carboxylic acid derivatives in the treatment of inflammatory diseases.

[0008] Technical solution: The thiophene-2-carboxylic acid derivatives represented by the general formula (I) of the present invention and their enantiomers, diastereomers, tautomers, N-oxides, solvates, physiologically hydrolyzable esters, preparations and pharmaceutically acceptable salts:

[0009] R 1 Selected from C n H 2n -COOR 5 、C n H 2n -CONHR 5 、C n H 2n -CN and tetrazole, wherein n is selected from 0, 1 and 2;

[0010] R 2 Selected from H or halogen;

[0011] R 3 Selected from C 5-10 A monocyclic aromatic group containing 1 to 4 C heteroatoms selected from N, O or S 5-14 Membered monocyclic heteroaryl, C 3-10 membered cycloalkyl or C 3-10 -membered heterocycloalkyl; said C 5-10 A monocyclic aromatic group containing 1 to 4 C heteroatoms selected from N, O or S 5-14 Membered monocyclic heteroaryl, C 3-10 membered cycloalkyl or C 3-10 The heterocycloalkyl groups are independently optionally substituted with 1 to 5 substituents selected from the group consisting of: 1-6 Alkyl, halogen, cyano, halo C 1-4 Alkyl, OH, C 1-6 Alkoxy, dimethylamino;

[0012] X is selected from O, S, and NH;

[0013] R 4 Selected from:

[0014] Among them, Ring is C 5-7 A monocyclic aromatic group containing 1 to 4 C heteroatoms selected from N, O or S 5-7 1-membered monocyclic heteroaryl;

[0015] R 5 Η、C 2-6 Alkyl, C 0-3 OOCCH3、C 0-3 OCNMe2、C 0-3 NMe2, C 2-6The alkyl group is unsubstituted or substituted with 1 to 6 substituents selected from the group consisting of F, OH, C l-3 Alkoxy, C 3-6 Cycloalkyl, aryl;

[0016] Among them, R 11 Selected from the following substituents: H, NO2, CN, OH, NH2, F, Cl, Br, I, C 1-6 Alkyl, halo-C 1-6 Alkyl, C 1-6 Alkoxy, halo-C 1-6 Alkoxy, C 0-6 Heteroalkyl-NR 7 R 8 、C 0-6 Heteroalkyl-COR 8 、C 0-6 Heteroalkyl-CO2R 8 、C 0-6 Heteroalkyl-CONR 7 R 8 、C0-6 heteroalkyl-SO3R 8 、C 0-6 Heteroalkyl-SO2NR 7 R 8 , or R 11 In the present invention, two adjacent substituents form a 3-8 membered saturated or unsaturated ring containing carbon atoms and optionally 1-3 heteroatoms selected from N, O or S;

[0017] R 7 is H;

[0018] R 8 Selected from H, C l-10 Alkyl, C 3-10 Cycloalkyl, C 3-10 Heterocycloalkyl, C l-10 Heteroalkyl-C 3-10 Cycloalkyl, C l-10 Heteroalkyl-C 3-10 Heterocycloalkyl, C l-10 Heteroalkyl-(5-membered heteroaryl), wherein the C l-10 Alkyl, C 3-10 Cycloalkyl, C 3-10 Heterocycloalkyl, C l-10 Heteroalkyl-C 3-10 Cycloalkyl, C l-10 Heteroalkyl-C 3-10 Heterocycloalkyl, C l-10 The alkyl, alkylene, cycloalkyl, heterocycloalkyl and heteroaryl groups of heteroalkyl-(5-membered heteroaryl) are unsubstituted or independently substituted with 1-7 substituents selected from the group consisting of: OR 9 、C 1-6Alkyl, CO2R 9 、CONR 9 R 10 NR 9 COR 9 、C 3-10 Heterocycloalkyl; R 9 Selected from H, C 1-6 Alkyl, where C 1-6 The alkyl group is unsubstituted or substituted by 1-6 substituents selected from the following: F, OC 1-3 alkyl.

[0019] The thiophene-2-carboxylic acid derivatives and their enantiomers, diastereomers, tautomers, N-oxides, solvates, physiologically hydrolyzable esters, preparations and pharmaceutically acceptable salts, R 1 Selected from CH2COOR 5 、COOR 5 or CONHR 5 ;

[0020] R 2 Selected from H, F, Cl, Br;

[0021] R 3 Selected from C 5-6 A monocyclic aromatic group containing 1 to 4 C heteroatoms selected from N, O or S 5-6 Membered monocyclic heteroaryl, C 5-6 membered cycloalkyl or C 5-6 -membered heterocycloalkyl; said C 5-6 A monocyclic aromatic group containing 1 to 4 C heteroatoms selected from N, O or S 5-6 Membered monocyclic heteroaryl, C 5-6 membered cycloalkyl or C 5-6 The heterocycloalkyl groups are independently optionally substituted with 1 to 5 substituents selected from the group consisting of: 1-6 Alkyl, halogen, cyano, halo C 1-4 Alkyl, OH, C 1-6 Alkoxy, dimethylamino.

[0022] The thiophene-2-carboxylic acid derivatives and their enantiomers, diastereomers, tautomers, N-oxides, solvates, physiologically hydrolyzable esters, preparations and pharmaceutically acceptable salts, R 1 Selected from COOR 5 ;

[0023] R 2 Selected from H or F;

[0024] R 3is selected from phenyl, pyridyl, pyrazinyl, pyrimidinyl, imidazolyl; said phenyl, pyridyl, pyrazinyl, pyrimidinyl, imidazolyl are independently optionally substituted by 1 to 5 substituents selected from the following: C 1-6 Alkyl, halogen, cyano, halo C 1-4 Alkyl, OH, C 1-6 Alkoxy, dimethylamino; X is selected from O, S, NH;

[0025] R 4 Selected from:

[0026] Ring is phenyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyrrolyl, thienyl, furanyl, thiazolyl, isothiazole, imidazolyl, pyrazolyl;

[0027] R 5 For Η, C2H5, C 2-3 Alkyl-C 3-6 Cycloalkyl, C 2-3 Alkyl-aryl, C 2-3 OOCCH3、C 2-3 OCNMe2、C 2-3 NMe2;

[0028] R 7 is H;

[0029] R 8 Selected from H, C 1-6 Alkyl, C 3-6 Cycloalkyl, CH2CONH2, CH2COMe2, CH2CH2OH, CH2CH2Me, (CH2)3OH, (CH3)3OMe, (CH2)4OH, (CH2)4OMe, (CH2)5OH, (CH2)2COOH, (CH2)3COO H, (CH2)4COOH, (CH2)5COOH, (CH2)2CH(CH3)COOH, C(CH2OH)3, C(CH2OH)2CH3, CH2CH(CH3)OH, (CH2)2CF3, (CH2)3CF3, (CH2)4CF3,

[0030] R 11 Selected from H, NO2, CN, OH, NH2, F, Cl, Br, I, C 1-6 Alkyl, halo-C 1-6 Alkyl, C 1-6 Alkoxy, halo-C 1-6 Alkoxy, COR 8 、CONR 7 R 8 、CO2R8 、SO2NR 7 R 8 、SO3R 8 .

[0031] The thiophene-2-carboxylic acid derivatives and their enantiomers, diastereomers, tautomers, N-oxides, solvates, physiologically hydrolyzable esters, preparations and pharmaceutically acceptable salts, R 4 Selected from:

[0032] Ring is phenyl, pyrimidinyl, pyridazinyl, or isothiazolyl;

[0033] R 11 Selected from H, NO2, CN, OH, NH2, F, Cl, Br, I, C 1-6 Alkyl, halo-C 1-6 Alkyl, C 1-6 Alkoxy, halo-C 1-6 Alkoxy, CONR 7 R 8 、CO2R 8 、SO2NR 7 R 8 、SO3R 8 ;

[0034] R 7 is H;

[0035] R 8 Selected from H, C 1-6 Alkyl, C 3-6 Cycloalkyl, CH2CONH2, CH2COMe2, CH2CH2OH, CH2CH2Me, (CH2)3OH, (CH3)3OMe, (CH2)4OH, (CH2)4OMe, (CH2 )2COOH, (CH2)3COOH, (CH2)4COOH, (CH2)2CH(CH3)COOH, C(CH2OH)3, C(CH2OH)2CH3, CH2CH(CH3)OH,

[0036] The thiophene-2-carboxylic acid derivatives and their enantiomers, diastereomers, tautomers, N-oxides, solvates, physiologically hydrolyzable esters, preparations and pharmaceutically acceptable salts, the compound of general formula (I) is preferably selected from the following compounds:

[0037] The method for preparing the thiophene-2-carboxylic acid derivative and its enantiomers, diastereomers, tautomers, N-oxides, solvates, physiologically hydrolyzable esters, preparations and pharmaceutically acceptable salts comprises the following steps:

[0038] (1) subjecting the compound of the general formula A to a nitration reaction to obtain a compound of the general formula B;

[0039] (2) Compound B of the general formula undergoes a substitution reaction with different phenol derivatives to obtain compound C of the general formula;

[0040] (3) Compound C of the general formula is first subjected to nitro reduction, then subjected to condensation reaction with different carboxylic acid or sulfonic acid derivatives, or subjected to substitution reaction with different hydrocarbon derivatives, and finally subjected to deprotection reaction to obtain compound D of the general formula;

[0041] Compound D is a compound of formula (I), R 1 、R 2 、R 3 、R 4 and X is the same as above.

[0042] A pharmaceutical composition comprising the compound of general formula (I) or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable excipient.

[0043] The compound of formula (I) or its pharmaceutically acceptable salt, or the pharmaceutical composition is used in the preparation of P2Y 14 Use of receptor antagonists in medicine.

[0044] Use of the compound of general formula (I) or its pharmaceutically acceptable salt or the pharmaceutical composition in preparing drugs for treating inflammatory diseases.

[0045] The drug is added with pharmaceutically acceptable excipients to prepare different dosage forms.

[0046] The pharmaceutically acceptable excipients refer to various conventional excipients required for the preparation of different dosage forms, such as diluents, binders, disintegrants, glidants, lubricants, flavoring agents, inclusion materials, adsorbents, etc., which are prepared by conventional preparation methods into any commonly used oral preparation, such as granules, powders, tablets, capsules, pills, oral liquids, decoctions, and drop pills.

[0047] Beneficial effects: Compared with the prior art, the present invention has the following advantages: The present invention discloses a type of P2Y 14 Thiophene-2-carboxylic acid derivatives and their pharmaceutically acceptable salts having inhibitory effects on P2Y receptors have been confirmed by pharmacological experiments. 14 The receptor has a significant inhibitory effect and can be used as a drug to treat inflammatory diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is THP-I cell UDPG / P2Y 14The relative expression of downstream proteins in the receptor signaling pathway, where data are mean ± standard deviation (n = 4), was analyzed by one-way anova ( #### Compared with the normal group, P < 0.0001. * Compared with the model control group, P < 0.05. # Compared with the model control group, P < 0.01. *** Indicates P<0.001 compared with the model control group, * *** represents the comparison with the model control group (P<0.0001);

[0049] Figure 2 is THP-I cell UDPG / P2Y 14 The relative expression of downstream proteins in the receptor signaling pathway, where data are mean ± standard deviation (n = 4), was analyzed by one-way anova ( #### Compared with the normal group, P < 0.0001. * Compared with the model control group, P < 0.05. # Compared with the model control group, P < 0.01. *** Indicates P<0.001 compared with the model control group, * *** represents the comparison with the model control group (P<0.0001);

[0050] Figure 3 is THP-I cell UDPG / P2Y 14 The relative expression of downstream proteins in the receptor signaling pathway, where data are mean ± standard deviation (n = 4), was analyzed by one-way anova ( #### Compared with the normal group, P < 0.0001. * Compared with the model control group, P < 0.05. # Compared with the model control group, P < 0.01. *** Indicates P<0.001 compared with the model control group, * *** represents the comparison with the model control group (P<0.0001);

[0051] Figure 4 is THP-I cell UDPG / P2Y 14 The relative expression of downstream proteins in the receptor signaling pathway, where data are mean ± standard deviation (n = 4), was analyzed by one-way anova ( #### Compared with the normal group, P < 0.0001. * Compared with the model control group, P < 0.05. # Compared with the model control group, P < 0.01. *** Indicates P<0.001 compared with the model control group, * ***represents the comparison with the model control group (P<0.0001);

[0052] FIG5 is a graph showing the IL-1β level in the supernatant of THP-1 cell culture medium, wherein the data are mean ± standard deviation, and variance analysis was performed using one-way anova ( #### Compared with the normal group, P < 0.0001. * Compared with the model control group, P < 0.05. # Compared with the model control group, P < 0.01. *** Indicates P<0.001 compared with the model control group, * *** represents the comparison with the model control group (P<0.0001);

[0053] FIG6 shows the gene expression levels of various inflammatory factors in mouse peritoneal fluid, wherein the data are mean ± standard deviation, and variance analysis was performed using one-way anova ( #### Compared with the normal group, P < 0.0001. * Compared with the model control group, P < 0.05. # Compared with the model control group, P < 0.01. *** Indicates P<0.001 compared with the model control group, * *** represents the comparison with the model control group (P<0.0001);

[0054] FIG7 shows the gene expression levels of various inflammatory factors in mouse peritoneal fluid, wherein the data are mean ± standard deviation, and variance analysis was performed using one-way anova ( #### Compared with the normal group, P < 0.0001. * Compared with the model control group, P < 0.05. # Compared with the model control group, P < 0.01. *** Indicates P<0.001 compared with the model control group, * *** represents the comparison with the model control group (P<0.0001);

[0055] FIG8 shows the gene expression levels of various inflammatory factors in mouse peritoneal fluid, wherein the data are mean ± standard deviation, and variance analysis was performed using one-way anova ( #### Compared with the normal group, P < 0.0001. * Compared with the model control group, P < 0.05. # Compared with the model control group, P < 0.01. *** Indicates P<0.001 compared with the model control group, * *** represents the comparison with the model control group (P<0.0001). DETAILED DESCRIPTION

[0056] The following examples are provided to illustrate the present invention in detail. The following examples are provided to better illustrate the present invention and are not intended to limit the scope of the present invention.

[0057] Example 1 and Example 2

[0058] Step 1: Ethyl 5-bromo-4-nitrothiophene-2-carboxylate (1a)

[0059] Ethyl 5-bromothiophene-2-carboxylate (5.00 g, 21.27 mmol) was added dropwise in portions to fuming nitric acid cooled to -20°C, maintaining the temperature below -20°C. The reaction was allowed to react for two hours at this temperature, and the reaction was complete as monitored by TLC. The reaction solution was added to ice water and extracted with ethyl acetate (3 times). The combined organic phases were washed with saturated brine and dried over anhydrous Na2SO4. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 50:1) afforded 2.15 g of a pale yellow solid in a 36.09% yield. 1 H NMR (300MHz, Chloroform-d) δ8.15 (s, 1H), 4.38 (q, J = 7.1Hz, 2H), 1.39 (t, J = 7.1Hz, 3H).

[0060] Step 2: Ethyl 5-(4-fluorophenoxy)-4-nitrothiophene-2-carboxylate (1b)

[0061] Ethyl 5-bromo-4-nitrothiophene-2-carboxylate (0.20 g, 0.71 mmol) was dissolved in N,N-dimethylformamide (4 mL). KCO (0.20 g, 1.43 mmol) and 4-fluorophenol (0.12 g, 1.07 mmol) were added and the mixture was stirred at room temperature for 4 h. After the reaction was complete, water was added and the mixture was extracted with ethyl acetate (3 times). The organic phases were combined, washed with saturated brine, and dried over anhydrous NaSO. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 20:1) afforded 0.21 g of a light yellow solid in a yield of 94.48%. 1 H NMR (300MHz, Chloroform-d) δ (ppm) 8.13 (s, 1H), 7.31 (dt, J = 6.7, 2.1Hz, 2H), 7.26–7.16 (m, 2H), 4.34 (q, J = 7.1Hz, 2H), 1.36 (t, J = 7.1Hz, 3H).

[0062] Step 3: Ethyl 5-(4-fluorophenoxy)-4-(4-methylbenzamido)thiophene-2-carboxylate (1)

[0063] Dissolve ethyl 5-(4-fluorophenoxy)-4-nitrothiophene-2-carboxylate (0.15 g, 0.48 mmol) in a 10 / 1 ethanol / water (5 ml) mixture. Add NH4Cl (0.26 g, 4.82 mmol). Slowly add iron powder (0.27 g, 4.82 mmol) at 0°C. After addition, continue stirring for 30 minutes and heat under reflux at 85°C for 4 hours. After the reaction is complete, filter through celite and remove the solvent under reduced pressure to obtain a yellow oil.

[0064] The product obtained in the previous step was dissolved in 4 ml of anhydrous tetrahydrofuran (THF) and triethylamine (0.98 g, 0.97 mmol) and 4-methylbenzoyl chloride (0.97 g, 0.63 mmol) were slowly added dropwise at 0°C. After addition, the mixture was stirred at room temperature for 4 hours. After the reaction was complete, water was added and the mixture was extracted with ethyl acetate (3 times). The organic phases were combined, washed with saturated brine, and dried over anhydrous Na2SO4. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 8:1) afforded 0.14 g of a pale yellow solid in a yield of 73.46%. 1 H NMR(300MHz,Chloroform-d)δ8.53(s,1H),7.85(s,1H),7.75(d,J=8.0Hz,2H),7.33( s,3H),7.23–7.08(m,4H),4.37(q,J=7.1Hz,2H),2.46(s,3H),1.40(t,J=7.1Hz,3H).

[0065] Step 4: 5-(4-fluorophenoxy)-4-(4-methylbenzamido)thiophene-2-carboxylic acid (2)

[0066] Ethyl 5-(4-fluorophenoxy)-4-(4-methylbenzamido)thiophene-2-carboxylate (100 mg, 0.253 mmol) was dissolved in a 1 / 1 methanol / tetrahydrofuran (2 ml) mixture. 1 mL of 4 mol / L LiOH solution was added and the mixture was stirred at room temperature for 5 h. After the reaction was complete, 1 N HCl was added to adjust the solution to pH 2. Stirring was continued for 30 min and filtered to yield 86 mg of a white solid with a yield of 92.57%. 1 H NMR (300MHz, DMSO-d6) δ10.10(s,1H),7.81(s,1H),7.77(d,J=8.1Hz,2H),7.29(d,J=7.9Hz,2H),7.27–7.21(m,4H),2.36(s,3H).

[0067] Example 3

[0068] The following compounds were prepared similarly to the methods of Examples 1 and 2:

[0069] Example 4 and Example 5

[0070] Step 1: Ethyl 5-((6-methylpyridin-3-yl)oxy)-4-nitrothiophene-2-carboxylate (4b)

[0071] Ethyl 5-bromo-4-nitrothiophene-2-carboxylate (0.20 g, 0.71 mmol) was dissolved in N,N-dimethylformamide (4 mL). KCO (0.20 g, 1.43 mmol) and 3-hydroxy-6-methylpyridine (0.12 g, 1.07 mmol) were added and the mixture was stirred at room temperature for 4 h. After the reaction was complete, water was added and the mixture was extracted with ethyl acetate (3 times). The organic phases were combined, washed with saturated brine, and dried over anhydrous NaSO. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 20:1) afforded 0.21 g of a pale yellow solid in a 94.48% yield. 1 H NMR(300MHz,DMSO-d6)δ8.65(d,J=2.9Hz,1H),8.07(s,1H),7.92(dd,J=8.6,3.0Hz,1 H), 7.47 (d, J = 8.6Hz, 1H), 4.27 (q, J = 7.1Hz, 2H), 2.55 (s, 3H), 1.25 (t, J = 7.1Hz, 3H).

[0072] Step 2: Ethyl 5-((6-methylpyridin-3-yl)oxy)-4-(4-methylbenzamido)thiophene-2-carboxylate (4)

[0073] Dissolve ethyl 5-((6-methylpyridin-3-yl)oxy)-4-nitrothiophene-2-carboxylate (0.15 g, 0.49 mmol) in a 10 / 1 ethanol / water (5 ml) mixture. Add NH4Cl (0.26 g, 4.87 mmol). Slowly add iron powder (0.27 g, 4.87 mmol) at 0°C. After addition, continue stirring for 30 minutes and heat under reflux at 85°C for 4 hours. After completion of the reaction, filter through celite and remove the solvent under reduced pressure to obtain a yellow oil.

[0074] The product obtained in the previous step was dissolved in 4 ml of anhydrous tetrahydrofuran (THF) and triethylamine (0.98 g, 0.97 mmol) and 4-methylbenzoyl chloride (0.98 g, 0.63 mmol) were slowly added dropwise at 0°C. After addition, the mixture was stirred at room temperature for 4 hours. After the reaction was complete, water was added and the mixture was extracted with ethyl acetate (3 times). The organic phases were combined, washed with saturated brine, and dried over anhydrous Na2SO4. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 8:1) afforded 0.13 g of a pale yellow solid in a 67.4% yield. 1 H NMR (300MHz, DMSO-d6) δ10.16(s,1H),8.38(d,J=3.0Hz,1H),7.92(s,1H),7.76(d,J=7.9Hz,2H),7.53(dd,J=8.6 ,3.0Hz,1H),7.29(dd,J=8.4,2.3Hz,3H),4.27(q,J=7.1Hz,2H),2.45(s,3H),2.36(s,3H),1.28(t,J=7.1Hz,3H).

[0075] Step 3: 5-((6-methylpyridin-3-yl)oxy)-4-(4-methylbenzamido)thiophene-2-carboxylic acid (5)

[0076] Ethyl 5-(4-fluorophenoxy)-4-(4-methylbenzamido)thiophene-2-carboxylate (100.00 mg, 0.253 mmol) was dissolved in a 1 / 1 methanol / tetrahydrofuran (2 ml) mixture. 1 mL of 4 mol / L LiOH solution was added and the mixture was stirred at room temperature for 5 h. After the reaction was complete, 1 N HCl was added to adjust the pH to 5-7. Stirring was continued for 30 min and filtered to yield 75.5 mg of a white solid with a yield of 77.75%. 1H NMR (300MHz, DMSO-d6) δ10.13(s,1H),8.37(d,J=3.0Hz,1H),7.85(s,1H),7.76(d,J=7. 8Hz, 2H), 7.51 (dd, J = 8.6, 3.0Hz, 1H), 7.28 (d, J = 8.1Hz, 3H), 2.43 (s, 3H), 2.35 (s, 3H).

[0077] Example 6

[0078] The following compounds were prepared similarly to the methods of Examples 4 and 5:

[0079] Example 7 and Example 8

[0080] Step 1: Ethyl 4-nitro-5-(p-tolylamino)thiophene-2-carboxylate (7b)

[0081] Ethyl 5-bromo-4-nitrothiophene-2-carboxylate (0.15 g, 0.53 mmol) was dissolved in toluene (3 mL), and palladium acetate (3.61 mg, 0.016 mmol), BINAP (13.34 mg, 0.021 mmol), and cesium carbonate (0.244 g, 0.750 mmol) were added. Under argon, the mixture was heated to 115°C. After 5 minutes, 4-methylaniline (0.069 g, 0.643 mmol) was added and the reaction was allowed to react for 4 hours. After completion of the reaction, the organic solvent was removed under reduced pressure, and the product was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 15:1) to obtain 0.92 g of a light yellow solid in a 56.09% yield. 1 H NMR(300MHz,DMSO-d6)δ10.76(s,1H),7.88(s,1H),7.43–7.37(m,2H),7.31 (d, J=8.4Hz, 2H), 4.21 (q, J=7.1Hz, 2H), 2.35 (s, 3H), 1.23 (t, J=7.1Hz, 3H).

[0082] Step 2: Ethyl 4-(4-methylbenzamido)-5-(p-tolylamino)thiophene-2-carboxylate (7)

[0083] Dissolve ethyl 4-nitro-5-(p-tolylamino)thiophene-2-carboxylate (0.15 g, 0.49 mmol) in a 10 / 1 ethanol / water (5 ml) mixture. Add NH4Cl (0.26 g, 4.90 mmol). Slowly add iron powder (0.27 g, 4.90 mmol) at 0°C. After addition, continue stirring for 30 minutes and heat under reflux at 85°C for 4 hours. After the reaction is complete, filter through celite and remove the solvent under reduced pressure to obtain a yellow oil.

[0084] The product obtained in the previous step was dissolved in 4 ml of anhydrous tetrahydrofuran (THF) and triethylamine (0.99 g, 0.99 mmol) and 4-methylbenzoyl chloride (0.98 g, 0.64 mmol) were slowly added dropwise at 0°C. After the addition was complete, the mixture was stirred at room temperature for 4 hours. After the reaction was complete, water was added and the mixture was extracted with ethyl acetate (3 times). The organic phases were combined, washed with saturated brine, and dried over anhydrous Na2SO4. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 8:1) afforded 0.12 g of a pale yellow solid in a 62.0% yield. 1H NMR (300MHz, DMSO-d6) δ9.82(s,1H),8.69(s,1H),7.87(d,J=8.1Hz,2H),7.79(s,1H),7.32(d,J= 8.0Hz, 2H), 7.13 (s, 4H), 4.23 (q, J = 7.1Hz, 2H), 2.38 (s, 3H), 2.25 (s, 3H), 1.27 (t, J = 7.1Hz, 4H).

[0085] Step 3: 4-(4-methylbenzamido)-5-(p-tolylamino)thiophene-2-carboxylic acid (8)

[0086] Ethyl 4-(4-methylbenzamido)-5-(p-tolylamino)thiophene-2-carboxylate (100.00 mg, 0.253 mmol) was dissolved in a 1 / 1 methanol / tetrahydrofuran (2 ml) mixture. 1 mL of 4 mol / L LiOH solution was added and the mixture was stirred at room temperature for 5 h. After the reaction was complete, 1 N HCl was added to adjust the pH to 5-7. Stirring was continued for 30 min and filtered to yield 45.5 mg of a white solid with a yield of 49.0%. 1 H NMR (300MHz, DMSO-d6) δ11.90(s,1H),10.28(s,1H),7.78(d,J=7.4Hz,2H),7.53(d,J =8.2Hz, 2H), 7.39 (d, J = 7.5Hz, 2H), 7.11 (d, J = 8.2Hz, 2H), 2.40 (s, 3H), 2.25 (s, 3H).

[0087] Example 9

[0088] The following compounds were prepared similarly to the methods of Examples 7 and 8:

[0089] Example 10 and Example 11

[0090] Step 1: Ethyl 4-nitro-5-(p-tolylthio)thiophene-2-carboxylate (7b)

[0091] Ethyl 5-bromo-4-nitrothiophene-2-carboxylate (0.20 g, 0.71 mmol) was dissolved in N,N-dimethylformamide (4 mL). KCO (0.20 g, 1.43 mmol) and 4-methylthiophenol (0.13 g, 1.07 mmol) were added and the mixture was stirred at room temperature for 4 h. After the reaction was complete, water was added and the mixture was extracted with ethyl acetate (3 times). The organic phases were combined, washed with saturated brine, and dried over anhydrous NaSO. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 20:1) afforded 0.16 g of a yellow solid in a 73.2% yield. 1 H NMR (300MHz, DMSO-d6) δ8.10 (s, 1H), 7.74–7.64 (m, 2H), 7.51–7.42 (m, 2H), 4.24 (q, J = 7.2Hz, 2H), 2.43 (s, 3H), 1.23 (t, J = 7.1Hz, 3H).

[0092] Step 2: Ethyl 4-(4-methylbenzamido)-5-(p-tolylthio)thiophene-2-carboxylate (7)

[0093] Dissolve ethyl 4-nitro-5-(p-tolylthio)thiophene-2-carboxylate (0.15 g, 0.46 mmol) in a 10 / 1 ethanol / water (5 ml) mixture. Add NH4Cl (0.25 g, 4.64 mmol). Slowly add iron powder (0.26 g, 4.64 mmol) at 0°C. After addition, continue stirring for 30 minutes and heat under reflux at 85°C for 4 hours. After completion of the reaction, filter through celite and remove the solvent under reduced pressure to obtain a yellow oil.

[0094] The product obtained in the previous step was dissolved in 4 ml of anhydrous tetrahydrofuran (THF) and triethylamine (0.94 g, 0.93 mmol) and 4-methylbenzoyl chloride (0.94 g, 0.60 mmol) were slowly added dropwise at 0°C. After addition, the mixture was stirred at room temperature for 4 hours. After the reaction was complete, water was added and the mixture was extracted with ethyl acetate (3 times). The organic phases were combined, washed with saturated brine, and dried over anhydrous Na2SO4. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 8:1) afforded 0.11 g of a pale yellow solid in a 57.6% yield. 1H NMR (300MHz, DMSO-d6) δ10.14(s,1H),7.99(s,1H),7.82(d,J=8.3Hz,2H),7.33(d,J=7.8Hz,2H),7.27(d,J =8.3Hz, 2H), 7.19 (d, J = 8.4Hz, 2H), 4.27 (q, J = 7.2Hz, 2H), 2.38 (s, 3H), 2.27 (s, 3H), 1.27 (t, J = 7.1Hz, 3H).

[0095] Step 3: 4-(4-methylbenzamido)-5-(p-tolylthio)thiophene-2-carboxylic acid (8)

[0096] Ethyl 4-(4-methylbenzamido)-5-(p-tolylamino)thiophene-2-carboxylate (100.00 mg, 0.253 mmol) was dissolved in a 1 / 1 methanol / tetrahydrofuran (2 ml) mixture. 1 mL of 4 mol / L LiOH solution was added and the mixture was stirred at room temperature for 5 h. After the reaction was complete, 1 N HCl was added to adjust the solution to pH 4. Stirring was continued for 30 min and filtered to yield 88.7 mg of a white solid with a yield of 95.0%. 1 H NMR (300MHz, DMSO-d6) δ10.10(s,1H),7.92(s,1H),7.83(d,J=8.2Hz,2H),7.31(d,J =8.2Hz, 2H), 7.23 (d, J = 8.2Hz, 2H), 7.16 (d, J = 8.4Hz, 2H), 2.36 (s, 3H), 2.25 (s, 3H).

[0097] Example 12

[0098] The following compounds were prepared similarly to the methods of Examples 10 and 11:

[0099] Example 13 and Example 14

[0100] Step 1: Ethyl 5-((6-methylpyridin-3-yl)oxy)-4-(benzamido)thiophene-2-carboxylate (13)

[0101] Dissolve ethyl 5-((6-methylpyridin-3-yl)oxy)-4-nitrothiophene-2-carboxylate (0.15 g, 0.49 mmol) in a 10 / 1 ethanol / water (5 ml) mixture. Add NH4Cl (0.26 g, 4.87 mmol). Slowly add iron powder (0.27 g, 4.87 mmol) at 0°C. After addition, continue stirring for 30 minutes and heat under reflux at 85°C for 4 hours. After completion of the reaction, filter through celite and remove the solvent under reduced pressure to obtain a yellow oil.

[0102] The product obtained in the previous step was dissolved in 4 ml of anhydrous tetrahydrofuran. Triethylamine (0.98 g, 0.97 mmol) and benzoyl chloride (0.85 g, 0.63 mmol) were slowly added dropwise at 0°C. After addition, the mixture was stirred at room temperature for 4 hours. After the reaction was complete, water was added and the mixture was extracted with ethyl acetate (3 times). The organic phases were combined, washed with saturated brine, and dried over anhydrous Na2SO4. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 8:1) afforded 0.11 g of a light yellow solid in a 57.6% yield. 1 H NMR (300MHz, DMSO-d6) δ10.36 (s, 1H), 8.55 (d, J = 2.9Hz, 1H), 7.95 (s, 1H), 7.83 (m, 3H),7.63–7.44(m,4H),4.29(q,J=7.1Hz,2H),2.53(s,3H),1.28(t,J=7.1Hz,3H).

[0103] Step 2: 5-((6-methylpyridin-3-yl)oxy)-4-(benzamido)thiophene-2-carboxylic acid (14)

[0104] Ethyl 5-((6-methylpyridin-3-yl)oxy)-4-(benzamido)thiophene-2-carboxylate (100.00 mg, 0.262 mmol) was dissolved in a 1 / 1 methanol / tetrahydrofuran (2 ml) mixture. 1 mL of 4 mol / L LiOH solution was added and the mixture was stirred at room temperature for 5 h. After the reaction was complete, 1 N HCl was added to adjust the solution to pH 4. Stirring was continued for 30 min and filtered to yield 83.5 mg of a white solid with a yield of 90.1%. 1 H NMR (300MHz, DMSO-d6) δ10.27(s,1H),8.38(d,J=3.1Hz,1H),7.84(dd,J=9.6,2.6 Hz, 3H), 7.62–7.50 (m, 2H), 7.50–7.41 (m, 2H), 7.28 (d, J = 8.6Hz, 1H), 2.43 (s, 3H).

[0105] Example 15

[0106] The following compounds were prepared similarly to the methods of Examples 13 and 14:

[0107] Example 13 and Example 14

[0108] Step 1: Ethyl 4-(6-methylnicotinamido)-5-((6-methylpyridin-3-yl)oxy)thiophene-2-carboxylate (16)

[0109] Dissolve ethyl 5-((6-methylpyridin-3-yl)oxy)-4-nitrothiophene-2-carboxylate (0.15 g, 0.49 mmol) in a 10 / 1 ethanol / water (5 ml) mixture. Add NH4Cl (0.26 g, 4.87 mmol). Slowly add iron powder (0.27 g, 4.87 mmol) at 0°C. After addition, continue stirring for 30 minutes and heat under reflux at 85°C for 4 hours. After completion of the reaction, filter through celite and remove the solvent under reduced pressure to obtain a yellow oil.

[0110] The product obtained in the previous step was dissolved in 4 ml of anhydrous dichloromethane. 6-Methylnicotinamide (0.10 g, 0.73 mmol), triethylamine (0.10 g, 0.97 mmol), and Carter's condensation agent (PyBOP) (0.38 mg, 0.73 mmol) were added sequentially. After the additions were complete, the reaction was stirred at room temperature for 10 hours. After the reaction was complete, the insoluble matter was removed by filtration. The filtrate was added with water and extracted with ethyl acetate (three times). The organic phases were combined, washed with saturated brine, and dried over anhydrous Na2SO4. Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 2:1) afforded 0.09 g of a white solid in a 43.6% yield. 1 H NMR (300MHz, DMSO-d6) δ10.43(s,1H),8.87(d,J=3.0Hz,1H),8.40(d,J=2.9Hz,1H),8.09(dd,J=8 .1,2.4Hz,1H),7.96(s,1H),7.56(dd,J=8.5,3.0Hz,1H),7.39(d,J=8.1Hz,1H),7.31(d,J=8.5Hz, 1H), 4.28 (q, J = 7.1Hz, 2H), 2.53 (s, 3H), 2.45 (s, 3H), 1.28 (t, J = 7.1Hz, 3H).

[0111] Step 2: 4-(6-methylnicotinamido)-5-((6-methylpyridin-3-yl)oxy)thiophene-2-carboxylic acid (17)

[0112] Ethyl 4-(6-methylnicotinamido)-5-((6-methylpyridin-3-yl)oxy)thiophene-2-carboxylate (100.00 mg, 0.262 mmol) was dissolved in a 1 / 1 methanol / tetrahydrofuran (2 ml) mixture. 1 mL of 4 mol / L LiOH solution was added and the mixture was stirred at room temperature for 5 h. After the reaction was complete, 1N HCl was added to adjust the solution to pH 5-6. Stirring was continued for 30 min and filtered to yield 56.0 mg of a white solid with a yield of 60.3%. 1 H NMR (300MHz, DMSO-d6) δ10.11(s,1H),8.54(s,1H),8.04(d,J=3.0Hz,1H),7.76(d,J=9.6Hz,1H),7.53(s, 1H), 7.19 (dd, J=8.5, 3.1Hz, 1H), 7.03 (d, J=8.1Hz, 1H), 6.95 (d, J=8.5Hz, 1H), 2.18 (s, 3H), 2.10 (s, 3H).

[0113] Example 18

[0114] The following compounds were prepared similarly to the methods of Examples 16 and 17:

[0115] The pharmacological experiments and results of some compounds of general formula I in the present invention are as follows:

[0116] Experimental methods:

[0117] Stable P2Y 14 The recipient HEK293 cell line was cultured in DMEM medium (containing 10% fetal bovine serum, 100 U / ml penicillin and 100 μg / ml streptomycin). Before the experiment, the cells were seeded into culture plates and switched to serum-free medium at a seeding density of 1×10 5 Cells were cultured at 37°C, 95% O2, and 5% CO2. IBMX was added to inhibit PDE activity to maintain a high level of cAMP. The AC agonist Forskolin (30 μM) was used to stimulate the production of cellular cAMP. Different concentrations of the test compound (0.01, 0.1, 1, 10, and 100 nm) were added in advance, with PPTN used as a positive control. 1 μM P2Y was then added. 14 Receptor agonist UDPG, cAMP Glo 4h later TM The intracellular cAMP content was detected using an assay kit (PROMEGA Co. Ltd, USA), and the inhibition rate was calculated based on the cAMP content.

[0118] Table 1 Effects of some compounds on P2Y at the cellular level14 Receptor inhibition rate value:

[0119] Experimental methods for pharmacological studies of the inhibitory effects of test compounds on LPS-induced macrophage inflammatory responses

[0120] Human THP-1 cells were cultured in RPMI-1640 medium (containing 10% fetal bovine serum, 100 U / ml penicillin, and 100 μg / ml streptomycin) and seeded into culture plates at a density of 1×10 5 Cells were cultured at 37°C, 95% O₂, and 5% CO₂. Before the experiment, 100 ng / ml PMA was added to each well and incubated for 24 hours to induce THP-1 cells to differentiate into macrophages. Test compound 5 (2.5, 5, and 10 μM) and PPTN (5 μM) were added to the culture medium for intervention. One hour later, LPS was added to the cells at a final concentration of 100 ng / ml. Three hours later, ATP was added at a final concentration of 5 mM. One hour later, the following parameters were measured:

[0121] Western Blot analysis of UDPG / P2Y in cells 14 Expression of downstream proteins in the receptor signaling pathway. The results are shown in Figures 1-4. LPS significantly increased the expression of P2Y14 receptor downstream related proteins in THP-1 cells, indicating successful model establishment. Different doses of the test compound were able to downregulate the expression of P2Y14 receptor downstream related proteins to varying degrees, showing significant differences compared with the model control group. PPTN also showed the expected effect, indicating that the experimental results are credible.

[0122] The IL-1β level in the cell culture supernatant was detected using an ELISA kit (Shenzhen Xinbosheng). The results are shown in Figure 5. LPS caused a significant increase in the IL-1β level in the THP-1 cell culture supernatant, indicating that the model was successfully established. Different doses of the test compound were able to downregulate the IL-1β level in the cell culture supernatant to varying degrees, and all showed significant differences compared with the model control group. PPTN also showed the expected effect, indicating that the experimental results were true and reliable.

[0123] Pharmacological experimental study method for the therapeutic effect of test compounds on acute peritonitis at the whole animal level

[0124] Male clean-grade ICR mice were housed with free access to food and water, 12 hours of lighting per day, and an ambient temperature of 25±2°C. The animals were divided into several groups: a normal control group, a model control group, and a drug-treated group (test compound and dexamethasone). An acute peritonitis model was induced by a single intraperitoneal injection of LSP, while the normal control group received an equal amount of saline injected into the joint cavity. Each drug-treated group was administered with test compound 5 (5, 10, and 20 mg / kg) and dexamethasone (10 mg / kg) via intra-articular injection. Six hours after injection, 8 mL of PBS was injected to collect peritoneal fluid. The levels of various inflammatory factors in the collected fluid were assayed. The results, as shown in Figures 6-8, show that LPS significantly increased the gene expression levels of various inflammatory factors in the mouse peritoneal fluid, confirming the success of the model establishment. Different doses of the test compound were able to downregulate the gene expression levels of various inflammatory factors to varying degrees, showing significant differences compared to the model control group. Dexamethasone also demonstrated the expected effect, indicating that the experimental results are reliable.

Claims

1. Thiophene-2-carboxylic acid derivatives represented by general formula (I) and their tautomers and pharmaceutically acceptable salts: R 1 Selected from COOR 5 ; R 2 is selected from H or halogen; R 3 is selected from phenyl, pyridyl, pyrazinyl, pyrimidinyl, imidazolyl; the phenyl, pyridyl, pyrazinyl, pyrimidinyl, imidazolyl are independently optionally substituted by 1 to 5 substituents selected from the following: 1-6 Alkyl, halogen, cyano, carboxyl, acetyl, methanesulfonyl, halo 1-4 Alkyl, halogenated C 1-4 Alkoxy, OH, C 1-6 Alkoxy, dimethylamino; X is selected from O, S, NH; R 4 Selected from: Ring is phenyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyrrolyl, thienyl, furanyl, thiazolyl, isothiazole, imidazolyl, pyrazolyl; R 5 Η、C 2-4 Alkyl, C 2-3 Alkyl-C 3-6 Cycloalkyl, C 2-3 OOCCH3、C 2-3 OCNMe2, C 2-3 NMe2; R 7 is H; R 8 Selected from H, C 1-6 Alkyl, C 3-6 Cycloalkyl, CH2CONH2, CH2COMe2, CH2CH2OH, CH2CH2Me, (CH2)3OH, (CH3)3OMe, (CH2)4OH, (CH2)4OMe, (CH2)5OH, (CH2)2COOH, (CH2)3COO H, (CH2)4COOH, (CH2)5COOH, (CH2)2CH(CH3)COOH, C(CH2OH)3, C(CH2OH)2CH3, CH2CH(CH3)OH, (CH2)2CF3, (CH2)3CF3, (CH2)4CF3, R 11 Selected from H, NO2, CN, OH, NH2, F, Cl, Br, I, C 1-6 Alkyl, halo-C 1-6 Alkyl, C 1-6 Alkoxy, halo-C 1-6 Alkoxy, COR 8 ,CONR 7 R 8 、CO2R 8 、SO2NR 7 R 8 、SO3R 8 .

2. The thiophene-2-carboxylic acid derivative and its tautomers and pharmaceutically acceptable salts according to claim 1, characterized in that: R 2 Selected from H or F; R 5 is H、C2H5、C 2-3 Alkyl-C 3-6 Cycloalkyl, C 2-3 OOCCH3、C 2-3 OCNMe2, C 2-3 NMe2.

3. The thiophene-2-carboxylic acid derivative and its tautomers and pharmaceutically acceptable salts according to claim 1, characterized in that: R 3 is selected from phenyl, pyridyl, pyrazinyl, pyrimidinyl, imidazolyl; the phenyl, pyridyl, pyrazinyl, pyrimidinyl, imidazolyl are independently optionally substituted by 1 to 2 substituents selected from the following: C 1-6 Alkyl, halogen, cyano, halo C 1-4 Alkyl, OH, C 1-6 Alkoxy, dimethylamino.

4. The thiophene-2-carboxylic acid derivative and its tautomers and pharmaceutically acceptable salts according to claim 3, characterized in that: R 4 Selected from: Ring is phenyl, pyrimidinyl, pyridazinyl, isothiazolyl; R 11 Selected from H, NO2, CN, OH, NH2, F, Cl, Br, I, C 1-6 Alkyl, halo-C 1-6 Alkyl, C 1-6 Alkoxy, halo-C 1-6 Alkoxy, CONR 7 R 8 、CO2R 8 、SO2NR 7 R 8 、SO3R 8 ; R 7 is H; R 8 Selected from H, C 1-6 Alkyl, C 3-6 Cycloalkyl, CH2CONH2, CH2COMe2, CH2CH2OH, CH2CH2Me, (CH2)3OH, (CH3)3OMe, (CH2)4OH, (CH2)4OMe, (CH2 )2COOH, (CH2)3COOH, (CH2)4COOH, (CH2)2CH(CH3)COOH, C(CH2OH)3, C(CH2OH)2CH3, CH2CH(CH3)OH, 5. The thiophene-2-carboxylic acid derivative and its tautomers and pharmaceutically acceptable salts according to claim 1, characterized in that: The compound of general formula (I) is selected from the following compounds:

6. A method for preparing the thiophene-2-carboxylic acid derivative and its tautomers and pharmaceutically acceptable salts according to claim 1, characterized in that: The steps include: (1) subjecting the compound of the general formula A to a nitration reaction to obtain a compound of the general formula B; (2) Compound B of the general formula undergoes a substitution reaction with different phenol derivatives to obtain compound C of the general formula; (3) Compound C of the general formula is first subjected to nitro reduction, then subjected to condensation reaction with different carboxylic acid or sulfonic acid derivatives, or subjected to substitution reaction with different hydrocarbon derivatives, and finally subjected to deprotection reaction to obtain compound D of the general formula; Compound D is a compound of formula (I), R 1 , R 2 , R 3 , R 4 and X is the same as that described in claim 1.

7. A pharmaceutical composition, characterized in that It contains the compound of general formula (I) as claimed in claim 1 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable excipient.

8. The compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1, or the pharmaceutical composition according to claim 7, in the preparation of P2Y 14 Use of receptor antagonists in medicine.

9. Use of the compound of general formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 or the pharmaceutical composition according to claim 7 in the preparation of a drug for treating inflammatory diseases.

10. The use according to claim 8 or 9, characterized in that The drug is added with pharmaceutically acceptable excipients to prepare different dosage forms.

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