Heterocyclic amide derivatives, processes for their preparation and use thereof

Abstract

The present application relates to a kind of heterocyclic amide derivatives and its preparation method and application. Specifically, it is related to a kind of compound of formula I and its preparation method and application, including the pharmaceutical composition or its pharmaceutically acceptable salt of active ingredient described compound. The present application further relates to the use of compound of formula (I) for treating and preventing EP4 mediated diseases.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical chemistry, specifically relating to a heterocyclic amide derivative, its preparation method, and its application. Background Technology

[0002] The characteristics and therapeutic applicability of prostaglandin receptors and their most commonly used selective agonists and antagonists have been extensively studied. Prostaglandins are mediators of pain, fever, and other inflammation-related symptoms. Prostaglandin E2 (PGE2) is the major metabolite of arachidic acid involved in inflammation. Furthermore, prostaglandin E2 is involved in various physiological and / or pathological symptoms, such as hyperalgesia, uterine contractions, gastrointestinal motility, arousal, inhibition of gastric acid secretion, blood pressure, platelet function, bone metabolism, angiogenesis, etc. The four subtypes of prostaglandin E2 receptors (EP1, EP2, EP3, and EP4) exhibit distinct pharmacological properties.

[0003] The EP4 receptor is characterized by having the longest intracellular C-terminal loop compared to other prostaglandin receptors. The EP4 receptor couples to a G protein and mediates elevated concentrations of cyclic adenosine monophosphate (cAMP). EP4 receptor expression is controlled by various physiological and pathophysiological processes, as it is involved in ovulation and fertilization, bone formation induction, T-cytokine signaling, prevention of inflammatory bowel disease, promotion of Langerhans cell migration and maturation, and mediating joint inflammation and other processes in collagen-induced arthritis models.

[0004] Studies have shown that EP4 receptor-mediated elevation of cAMP levels is a major signal leading to immunosuppression by immune cells. In mice with APCmin mutations, EP4 knockout showed a delayed tumorigenesis compared to wild animals, indicating the pro-tumorigenic activity of PGE2-EP4 signaling in host immune cells.

[0005] Therefore, the compounds disclosed in this invention are expected to have therapeutic effects on diseases or discomforts mediated by the EP4 receptor in mammals, including humans, including acute and chronic pain, osteoarthritis, rheumatoid arthritis, and cancer.

[0006] In summary, there remains an urgent need in the field for novel compounds that can effectively and reliably inhibit EP4 both in vitro and in vivo. Summary of the Invention

[0007] The object of this invention is to provide a class of novel compounds that have EP4 receptor inhibitory activity and / or good pharmacodynamic / pharmacokinetic properties and can be used as EP4 receptor antagonists, as well as pharmaceutically acceptable salts thereof, and pharmaceutical compositions thereof as active ingredients, and their use in treating or alleviating EP4 receptor-related diseases such as prostaglandin EP4 receptor-mediated diseases.

[0008] In a first aspect, the present invention provides a compound of formula I or a pharmaceutically acceptable salt, hydrate, solvate, stereoisomer, isotopic compound or prodrug thereof;

[0009]

[0010] in,

[0011] R1 is independently selected from the group consisting of: hydrogen, halogen, substituted or unsubstituted C. 1-6 Alkyl, substituted or unsubstituted C 3-6 cycloalkyl;

[0012] R2 and R3 are each independently selected from the following group: hydrogen, substituted or unsubstituted C. 1-6 Alkyl, substituted or unsubstituted C 3-6 Cycloalkyl; or, R2 and R3 together with the carbon atom attached to them to form C 3-6 Carbon rings or 3- to 6-membered heterocycles; the heterocycles comprise one or two independently selected from S, O, or NR. b The ring members; and, the C 3-6 The carbon ring or 3 to 6-membered heterocycle may optionally be replaced by one or more R1s;

[0013] R b Each is independently selected from the following group: hydrogen, substituted or unsubstituted C. 1-6 Alkyl, substituted or unsubstituted C 3-6 cycloalkyl, substituted or unsubstituted C 6-10 aryl, substituted or unsubstituted 5- to 6-membered heteroaryl, -C(O)R c -S(O)2R c ;

[0014] R c Each is independently selected from the following group: substituted or unsubstituted C 1-6 Alkyl, substituted or unsubstituted C 3-6 Carbocyclic rings, substituted or unsubstituted 3- to 6-membered heterocycles, substituted or unsubstituted C 6-10 Aryl, substituted or unsubstituted 5 to 10-membered heteroaryl;

[0015] R4 and R5 are each independently selected from the following group: hydrogen, substituted or unsubstituted C. 1-3 Alkyl group; or, R4 and R5, together with the carbon atom attached to them, constitute a substituted or unsubstituted C14. 3-6 Carbocyclic rings (such as cyclopropyl);

[0016] R6 represents a group that is absent or selected from the following groups: halogen, cyano, haloalkyl (such as trifluoromethyl);

[0017] Unless otherwise specified, substitution refers to the replacement of one or more (e.g., 1, 2, or 3) hydrogen atoms in a group by substituents selected from the group consisting of: halogens (e.g., F), C... 1-4 Alkyl, C 1-4 Halogenated alkyl groups.

[0018] In another preferred embodiment, the substituted or unsubstituted C 1-6 Alkyl group is C 1-6 Alkyl or C 1-6 Haloalkyl; preferably, C10. 1-6 Alkyl or C 1-6 Fluorinated alkyl groups.

[0019] In another preferred embodiment, the substituted or unsubstituted C 3-6 Cycloalkyl group is C 3-6 cycloalkyl or C 3-6 Halogenated cycloalkyl; preferably, C10. 3-6 Alkyl or C 3-6 Fluorinated cycloalkyl groups.

[0020] In another preferred embodiment, R1 is independently selected from the group consisting of: hydrogen, halogens, and C. 1-6 Alkyl, C 3-6 cycloalkyl, C 3-6 Fluorinated cycloalkyl, C 1-6 Fluorinated alkyl groups;

[0021] R2 and R3 are each independently selected from the following groups: hydrogen, C 1-6 Alkyl, C 3-6 cycloalkyl, C 3-6 Fluorocycloalkyl, C 1-6 Fluoroalkyl groups; or, R2 and R3 together with the carbon atom attached to them constitute C. 3-6 Carbon rings or 3- to 6-membered heterocycles; wherein the heterocycles comprise one or two independently selected from S, O, or NR. b The ring members; and, the C 3-6 The carbon ring or 3 to 6-membered heterocycle may also be optionally replaced by R1;

[0022] R b Selected from the following group: hydrogen, C 1-6 Alkyl, C 3-6 cycloalkyl, C 3-6 Fluorocycloalkyl, C 1-6 fluoroalkyl, C 6-10 Aryl, 5- to 10-membered heteroaryl, C(O)-C 1-6 Alkyl, C(O)-C 6-10 Aryl, S(O)2-C 1-6 Alkyl, S(O)2-C 6-10 Aryl;

[0023] R4 and R5 are each independently hydrogen or C. 1-3 alkyl;

[0024] R6 represents no substituent or a substituent selected from the group consisting of halogen, cyano, and trifluoromethyl.

[0025] In another preferred embodiment, R1 is selected from the group consisting of: hydrogen, halogens, and C. 1-6 Alkyl, C 3-6 cycloalkyl;

[0026] In another preferred embodiment, R2 and R3 are each independently selected from hydrogen and C. 1-6 Alkyl groups, or R2 and R3, together with the carbon atom attached to them, constitute a cyclopropyl group.

[0027] In another preferred embodiment, R4 and R5 are each independently hydrogen or methyl.

[0028] In another preferred embodiment, when R6 is not absent, R6 is located adjacent to or between -SF5.

[0029] In another preferred embodiment, R6 represents no substituent or a substituent selected from the group consisting of halogens.

[0030] In another preferred embodiment, R1, R2, R3, R4, R5, R6, R b and R c Each of these is a corresponding group in the example compounds (such as those listed in Table 1).

[0031] In another preferred embodiment, the compound of formula I, or a pharmaceutically acceptable salt, hydrate, solvate, stereoisomer, isotope compound, or prodrug thereof, is selected from the group consisting of:

[0032]

[0033] In a second aspect of the invention, a pharmaceutical composition is provided comprising a compound of formula I as described in the first aspect or a pharmaceutically acceptable salt, hydrate, solvate, stereoisomer, isotopic compound or prodrug thereof, and a pharmaceutically acceptable carrier or diluent.

[0034] In a third aspect of the invention, there is provided the use of a compound of formula I as described in the first aspect or a pharmaceutically acceptable salt, hydrate, solvate, stereoisomer, isotope compound or prodrug thereof, or a pharmaceutical composition as described in the second aspect, in the preparation of (i) a medicament for inhibiting EP4 receptor activity and / or (ii) a medicament for treating or preventing diseases related to the EP4 receptor and / or (iii) an EP4 receptor antagonist.

[0035] In another preferred embodiment, the EP4 receptor-related diseases include diseases mediated by prostaglandin E2 and / or prostaglandin EP4 receptors.

[0036] In another preferred embodiment, the EP4 receptor-related diseases include: acute and chronic pain, osteoarthritis, rheumatoid arthritis, cancer, or combinations thereof.

[0037] In a fourth aspect of the invention, a method for treating or preventing EP4 receptor-related diseases is provided, the method comprising administering to a subject in need a therapeutically effective amount of a compound of formula I as described in the first aspect or a pharmaceutically acceptable salt, hydrate, solvate, stereoisomer, isotopic compound or prodrug thereof, or a pharmaceutical composition as described in the second aspect.

[0038] In another preferred embodiment, the subject in need refers to a subject who has been identified or diagnosed with EP4 receptor-related disease.

[0039] In a fifth aspect of the invention, a method for inhibiting EP4 receptor activity in cells or a subject is provided, the method comprising the steps of contacting the cells with or administering to the subject a compound of formula I as described in the first aspect or a pharmaceutically acceptable salt, hydrate, solvate, stereoisomer, isotope compound or prodrug or a pharmaceutical composition as described in the second aspect.

[0040] In another preferred embodiment, the cell is a mammalian cell.

[0041] In another preferred embodiment, when the method is used to inhibit cells, the method is in vitro and non-therapeutic.

[0042] In another preferred embodiment, the subject is a mammal, preferably a human.

[0043] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Detailed Implementation

[0044] Through extensive and in-depth research, the inventors unexpectedly discovered a class of compounds with novel structures exhibiting good EP4 receptor inhibitory activity. Furthermore, the inventors also found that these compounds with novel structures possess excellent pharmacodynamic / pharmacokinetic properties. Based on these findings, the present invention was completed.

[0045] the term

[0046] In this invention, unless otherwise specified, the terms used have the general meanings known to those skilled in the art.

[0047] When a substituent is described using a conventional chemical formula written from left to right, it also includes chemically equivalent substituents obtained when the structural formula is written from right to left. For example, -CH2O- is equivalent to -OCH2-.

[0048] As used herein, the term "alkyl" itself, or as part of another substituent, refers to a straight-chain or branched hydrocarbon group having a specified number of carbon atoms (i.e., C64-C ... 1-6 This refers to one to six carbon atoms. Preferably, alkyl groups generally contain 1-6 carbon atoms, i.e., C64-C ... 1-6 Alkyl groups. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, and similar alkyl groups. One or more (e.g., 1-4) positions of the alkyl group may optionally be substituted, and the substitution may occur at any position in the group.

[0049] As used herein, the term "haloalkyl" refers to a branched and straight-chain saturated aliphatic hydrocarbon group having a specified number of carbon atoms and substituted with one or more halogens. Examples of haloalkyl groups include, but are not limited to, fluoromethyl, difluoromethyl, trifluoromethyl, trichloromethyl, pentafluoroethyl, pentachloroethyl, 2,2,2-trifluoroethyl, heptafluoropropyl, and heptachloropropyl. Examples of haloalkyl groups also include "fluoroalkyl" groups having a specified number of carbon atoms and substituted with one or more fluorine atoms in a branched and straight-chain saturated aliphatic hydrocarbon group.

[0050] The terms “fluoroalkyl” or “fluoroalkyl” refer to alkyl groups as defined above, wherein one or more hydrogen atoms are replaced by fluorine atoms.

[0051] The term "alkoxy" refers to a straight-chain, branched, or cyclic alkyl group linked by an ether oxygen atom, with its free valence derived from that ether oxygen atom. Representative examples include (but are not limited to): methoxy, ethoxy, propoxy, isopropoxy, and butoxy, etc. Preferably, C10 is used. 1-3 Alkyl group.

[0052] The term "fluoroalkoxy" or "fluoroalkoxy" refers to an alkoxy group as defined above, in which one or more hydrogen atoms are replaced by fluorine atoms.

[0053] The term "haloalkoxy" refers to -O-haloalkyl, including straight-chain, branched, or cyclic haloalkoxy, and representative examples include (but are not limited to): fluoromethoxy, difluoromethoxy, trifluoromethoxy, trichloromethoxy, pentafluoroethoxy, and pentachloroethoxy.

[0054] The term "cycloalkyl" or "carbocyclic" refers to cyclic alkyl groups that include saturated monocyclic, bicyclic, or polycyclic forms, such as C1646. 3-8 Or C 3-12 Cycloalkyl. C 3-8Cycloalkyl refers to cycloalkyl groups including C3, C4, C5, C6, C7, or C8 cycloalkyl groups. Cycloalkyl groups may also include spirocyclic, bridged, and fused ring structures. Representative cycloalkyl groups of this invention include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and norbornel. It should be understood that substituted or unsubstituted cycloalkyl groups, such as branched cycloalkyl groups (e.g., 1-methylcyclopropyl and 2-methylcyclopropyl), are included in the definition of "cycloalkyl". 5-12 Dense bicyclic fingers include C5, C6, C7, C8, C9, and C6. 10 C 11 C 12 Bicycloalkyl groups, including but not limited to: C. 5-12 The double-ring finger includes C5, C6, C7, C8, C9, and C 10 C 11 C 12 Bicycloalkyl groups, including but not limited to: In this invention, the cycloalkyl group preferably contains 3 to 6 carbon atoms (i.e., C64). 3-6 Monocyclic cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl.

[0055] The term "aryl" or "aromatic group," alone or as part of a group such as "aralkyl," "aralkyloxy," or "aryloxyalkyl," refers to a monocyclic, bicyclic, or tricyclic ring system (preferably 6-10 membered aromatic rings) having a total of 5 to 15 ring members (or ring atoms), wherein at least one ring in the system is aromatic and each ring in the system contains 3 to 7 ring members. "Aryl" can be substituted or unsubstituted. In some embodiments of the invention, "aryl" refers to an aromatic ring system, including but not limited to phenyl, biphenyl, indenyl, 1-naphthyl, 2-naphthyl, and tetrahydronaphthyl. Fused aryl groups can be attached to another group at a suitable position on a cycloalkyl or aromatic ring. Connecting lines drawn from the ring system indicate that the bond can be attached to any suitable ring atom.

[0056] The term "heteroaryl" or "heterocyclic aromatic group" refers to a heteroaromatic system containing 1-4 heteroatoms and 5-14 ring atoms, wherein the heteroatoms are selected from oxygen, nitrogen, and sulfur. Heteroaryl groups are preferably 5- to 10-membered rings, more preferably 5- or 6-membered, such as pyrroleyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, thiadiazolyl, isothiazolyl, furanyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, triazolyl, and tetrazolyl. "Heteroaryl" can be substituted or unsubstituted. When substituted, the substituent is preferably one or more of the following groups, independently selected from alkyl, deuteralkyl, haloalkyl, alkoxy, haloalkoxy, alkenyl, alkynyl, alkylthio, alkylamino, halogen, amino, nitro, hydroxyl, mercapto, cyano, cycloalkyl, heterocyclic, aryl, heteroaryl, cycloalkylthio, oxo, carboxyl, and carboxylic acid ester.

[0057] The term "heterocyclic alkyl" or "heterocycle" refers to a cycloalkyl group containing one to five heteroatoms selected from N, O, and S, wherein the nitrogen and sulfur atoms are optionally oxidized, and the nitrogen atom is optionally quaternized. Heterocyclic alkyl groups can be monocyclic, bicyclic, or polycyclic systems. Non-limiting examples of heterocyclic alkyl groups include pyrrolidine, imidazoline, pyrazolidine, butyrolactam, valeron, imidazolidinone, hydantoin, dioxolane, benzodiimide, piperidine, 1,4-dioxane, morpholine, thiomorpholine, thiomorpholine-S-oxide, thiomorpholine-S,S-oxide, piperazine, pyran, pyridone, 3-pyrrolidine, thiaran, pyranone, tetrahydrofuran, tetrahydrothiophene, quinine ring, etc. Heterocyclic alkyl groups can be attached to the rest of the molecule via a cyclic carbon or heteroatom.

[0058] The term "hydroxyl group" refers to -OH.

[0059] The term "nitro" refers to -NO2.

[0060] The term "amino" refers to -NH2.

[0061] The term "halogenated" or "halogen" includes fluorine, chlorine, bromine, and iodine.

[0062] The term "cyano" refers to -CN.

[0063] In this invention, each of the alkyl, haloalkyl, aryl, heteroaryl, alkenyl, alkynyl, etc. groups mentioned above may be substituted or unsubstituted.

[0064] In this invention, the term "substitution" refers to the substitution of one or more hydrogen atoms on a specific group by a specific substituent. The specific substituent is the substituent described accordingly above, or the substituent appearing in the various embodiments. Unless otherwise specified, a substituted group may have a substituent selected from a specific group at any substituted site of that group, and the substituents may be the same or different at each position. Those skilled in the art will understand that the combinations of substituents contemplated in this invention are those that are stable or chemically feasible. Typical substitutions include, but are not limited to, one or more of the following groups: such as hydrogen, deuterium, halogen (e.g., monohalogen substituents or polyhalogen substituents, the latter such as trifluoromethyl or alkyl containing Cl3), nitrile, nitro, oxo (e.g., =O), trifluoromethyl, trifluoromethoxy, cycloalkyl, alkenyl, alkynyl, heterocyclic, aromatic, OR a SR a S(=O)R e S(=O)2R e P(=O)2R e S(=O)2OR e P(=O)2OR e NR b R c NR b S(=O)2R e NR b P(=O)2R e S(=O)2NR b R c P(=O)2NR b R c C(=O)OR d C(=O)R a C(=O)NR b R c OC(=O)R a OC (=O)NR b R c NR b C(=O)OR e NR d C(=O)NR b R c NR d S(=O)2NR b R c NR d P(=O)2NR b R c NR b C(=O)R a , or NR b P(=O)2R e , where Ra It can independently represent hydrogen, deuterium, alkyl, cycloalkyl, alkenyl, ynyl, heterocyclic, or aromatic rings, R b R c and R d It can independently represent hydrogen, deuterium, alkyl, cycloalkyl, heterocyclic or aromatic ring, or R b and R c It can form heterocycles together with N atoms; R e It can independently represent hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, heterocyclic, or aromatic rings. The above-mentioned typical substituents, such as alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, heterocyclic, or aromatic rings, can be optionally substituted. Such substituents include (but are not limited to): halogen, hydroxyl, cyano, carboxyl (-COOH), C... 1-6 Alkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 Cycloalkyl, 3-12 membered heterocyclic, aryl, heteroaryl, C 1-8 Aldehyde group, C 2-10 Acyl group, C 2-10 Ester group, amino group, C 1-6 Alkoxy, C 1-10 sulfonyl and C 1-6 Urea, etc.

[0065] Unless otherwise stated, it is assumed that any heteroatom in a suboptimal valence state has enough hydrogen atoms to compensate for its valence state.

[0066] When the substituent is a non-terminal substituent, it is a subunit of the corresponding group. For example, alkyl corresponds to alkylene, cycloalkyl corresponds to cycloalkylene, heterocyclic corresponds to heterocyclic, alkoxy corresponds to alkoxy, etc.

[0067] The term “EP4 antagonist” refers to a compound that inhibits or blocks cell signal transduction triggered by the interaction between PGE2 and the EP4 receptor, including but not limited to compounds of formula (I) described herein.

[0068] The term "treatment" refers to reducing, inhibiting, and / or reversing cancer progression in a subject for whom it is needed. The term "treatment" includes any indicator of successful treatment or improvement of cancer, including any objective or subjective parameters such as reduction; remission; relief of symptoms or making the subject more tolerant of harm, pathology, or symptom; delay or slowing of the rate of progression, etc. Measurements of treatment or improvement may be based on, for example, the results of physical examinations, pathological examinations, and / or diagnostic tests known in the art. Treatment can also refer to a reduction in the occurrence or onset of cancer, or its recurrence (e.g., prolonged remission time), compared to what would happen without intervention.

[0069] The term "cancer" can include cancers resulting from genetic mutations. Examples of such cancers include, but are not limited to, breast cancer; cancers associated with Lee-Flaumeni syndrome, such as childhood sarcoma, leukemia, and brain cancer; cancers associated with Lynch syndrome, such as colon cancer, bile duct cancer, brain cancer, endometrial cancer, kidney cancer, ovarian cancer, pancreatic cancer, small intestine cancer, stomach cancer, and ureteral cancer; lung cancer; melanoma; prostate cancer; retinoblastoma; thyroid cancer; and uterine cancer. Furthermore, cancer can be the result of acquired mutations, such as mutations caused by diet, environment, and / or lifestyle, or somatic mutations. Examples of such cancers may include, but are not limited to, adrenal carcinoma, adrenocortical carcinoma, bladder cancer, brain cancer, primary brain cancer, glioma, glioblastoma, breast cancer, cervical cancer, colon cancer (non-limiting examples include colorectal cancers such as colonic adenocarcinoma and colon cancer), endometrial cancer, epidermal cancer, esophageal cancer, gallbladder cancer, genitourinary tract cancer, head and neck cancer, kidney cancer, liver cancer, lung cancer (non-limiting examples include adenocarcinoma, small cell lung cancer and non-small cell lung cancer), lymphoma (non-limiting examples include B-cell lymphoma, T-cell lymphoma, Hodgkin lymphoma, non-Hodgkin lymphoma), melanoma, malignant melanoma, malignant carcinoid, malignant pancreatic insulinoma, myeloma, multiple myeloma, ovarian cancer, pancreatic cancer (e.g., exocrine pancreatic cancer), prostate cancer, renal cell carcinoma, skin cancer, and, for example, squamous cell carcinoma, gastric cancer, testicular cancer, thyroid cancer, and thyroid follicle cancer, among others. Follicular carcinoma, Wilms' tumor, choriocarcinoma, fungal infection, malignant hypercalcemia, cervical hyperplasia, leukemia, acute lymphoblastic leukemia, chronic lymphocytic leukemia, pilocellular lymphoma, Burkholderia lymphoma, acute myeloid leukemia, chronic myeloid leukemia, myelodysplastic syndrome, promyelocytic leukemia, chronic myeloid leukemia, acute myeloid leukemia, fibrosarcoma, habdomyosarcoma, astrocytoma, neuroblastoma, rhabdomyosarcoma, schwannoma, Kaposi's sarcoma, polycythemia vera, essential thrombocythemia, Hodgkin's disease, non-Hodgkin's lymphoma, soft tissue sarcoma, osteosarcoma, primary macroglobulinemia, seminoma, teratoma, osteosarcoma, xenodermal melanoma, keratokeratoma, and retinoblastoma.

[0070] Active ingredients

[0071] As used herein, the terms “compound of the invention” or “active ingredient of the invention” are used interchangeably to refer to a compound of formula I, or a pharmaceutically acceptable salt, hydrate, solvate, stereoisomer, isotopic compound (such as a deuterated compound), or prodrug thereof. The term also includes racemic mixtures and optical isomers.

[0072] The compounds of the present invention have the structure shown in Formula I.

[0073]

[0074] Among them, R1, R2, R3, R4, R5 and R6, R b R c As defined above.

[0075] In this invention, the salts that the compounds may form are also within the scope of this invention. Unless otherwise stated, the compounds of this invention are understood to include their salts. As used herein, the term "salt" refers to a salt formed in an acidic or basic form by an inorganic or organic acid and a base. Furthermore, when a compound of this invention contains a basic segment, it includes, but is not limited to, pyridine or imidazole; when it contains an acidic segment, it includes, but is not limited to, carboxylic acids; and any zwitterions ("internal salts") that may form are included within the scope of the term "salt." Pharmaceutically acceptable (i.e., non-toxic and physiologically acceptable) salts are preferred, although other salts are also useful, for example, for separation or purification steps in the preparation process. The compounds of this invention may form salts, for example, by reacting compound I with a certain amount, such as an equimolar amount, of an acid or base, precipitating it in a medium, or by freeze-drying it in an aqueous solution.

[0076] The compounds of this invention contain basic fragments or portions, including but not limited to amines, pyridines, or imidazole rings, which may form salts with organic or inorganic acids. Typical acids that can form salts include acetates (such as acetic acid or trihaloacetic acids, such as trifluoroacetic acid), adipates, alginates, ascorbic acid salts, aspartate salts, benzoates, benzenesulfonates, hydrogen sulfates, borates, butyrates, citrates, camphor salts, camphor sulfonates, cyclopentanepropionate, diethylene glycol salts, dodecyl sulfates, ethanesulfonates, fumarates, glucono-2-phosphates, glycerol phosphates, hemisulfates, heptarates, hexanoates, hydrochlorides, hydrobromide, and hydroiodide. Salts, hydroxyethanesulfonates (e.g., 2-hydroxyethanesulfonate), lactates, maleates, methanesulfonates, naphthalenesulfonates (e.g., 2-naphthalenesulfonate), nicotinates, nitrates, oxalates, pectates, persulfates, phenylpropionates (e.g., 3-phenylpropionates), phosphates, picrates, neopentanoates, propionates, salicylates, succinates, sulfates (e.g., those formed with sulfuric acid), sulfonates, tartrates, thiocyanates, toluenesulfonates such as p-toluenesulfonate, dodecanoates, etc.

[0077] Some compounds of this invention may contain acidic fragments or portions, including but not limited to carboxylic acids, which may form salts with various organic or inorganic bases. Typical base-formed salts include ammonium salts, alkali metal salts such as sodium, lithium, and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, and salts formed with organic bases (such as organic amines), such as benzylamine, dicyclohexylamine, hepatopanylamine (a salt formed with N,N-di(dehydroabietic)ethylenediamine), N-methyl-D-glucosamine, N-methyl-D-glucosamide, tert-butylamine, and salts formed with amino acids such as arginine, lysine, etc. Basic nitrogen-containing groups can react with quaternary ammonium halides, such as small alkyl halides (e.g., chlorides, bromides, and iodides of methyl, ethyl, propyl, and butyl halides), dialkyl sulfates (e.g., dimethyl sulfate, diethyl sulfate, dibutyl sulfate, and dipentyl sulfate), long-chain halides (e.g., chlorides, bromides, and iodides of decyl, dodecyl, tetradecyl, and tetradecyl halides), aralkyl halides (e.g., benzyl and phenyl bromides), etc.

[0078] The prodrugs and solvates of the compounds in this invention are also included within the scope of this invention. Here, the term "prodrug" refers to a compound that, in the course of treating a related disease, undergoes a metabolic or chemical transformation to produce the compounds, salts, or solvates of this invention. The compounds of this invention include solvates, such as hydrates. As used herein, the term "solvate" refers to a complex formed by the coordination of the compound of this invention with a solvent molecule in a specific ratio. As used herein, the term "hydrate" refers to a complex formed by the coordination of the compound of this invention with water, such as a monohydrate.

[0079] The compounds, salts, or solvates of this invention may exist in tautomer forms (e.g., amides and imine ethers). All such tautomers are part of this invention.

[0080] All stereoisomers of compounds (e.g., those with asymmetric carbon atoms due to various substitutions), including their enantiomers and diastereomeric forms, are within the scope of this invention. The independent stereoisomers of the compounds in this invention may not coexist with other isomers (e.g., possessing special activity as a pure or substantially pure optical isomer), or may be mixtures, such as racemates, or mixtures formed with all other stereoisomers or a portion thereof. The chiral center of this invention has two configurations, S or R, as defined by the International Union of Theoretical and Applied Chemistry (IUPAC) in 1974. Racemic forms can be resolved by physical methods, such as stepwise crystallization, or by derivatization into diastereomers followed by crystallization, or by chiral column chromatography. Individual optical isomers can be obtained from racemates by suitable methods, including but not limited to conventional methods, such as recrystallization after salting with an optically active acid.

[0081] The compounds of this invention, obtained sequentially through preparation, separation, and purification, have a weight content equal to or greater than 90%, for example, equal to or greater than 95%, or equal to or greater than 99% (“very pure” compounds), as listed in the text description. Such “very pure” compounds of this invention are also included as part of this invention.

[0082] All configurational isomers of the compounds of this invention are included within the scope of this invention, whether in mixture, pure, or very pure form. The definition of the compounds of this invention includes both cis (Z) and trans (E) olefin isomers, as well as cis and trans isomers of carbocyclic and heterocyclic compounds.

[0083] Throughout the specification, groups and substituents can be selected to provide stable fragments and compounds.

[0084] Some compounds of this invention may exist in specific geometric or stereoisomeric forms. This invention covers all compounds, including their cis and trans isomers, R and S enantiomers, diastereomers, (D) isomers, (L) isomers, racemic mixtures, and other mixtures. Additionally, the asymmetric carbon atom may represent a substituent, such as an alkyl group. All isomers and mixtures thereof are included in this invention.

[0085] According to the present invention, the ratio of isomers in a mixture of isomers can be varied. For example, a mixture containing only two isomers can have the following combinations: 50:50, 60:40, 70:30, 80:20, 90:10, 95:5, 96:4, 97:3, 98:2, 99:1, or 100:0. All ratios of isomers are within the scope of the present invention. Similar ratios readily understood by those skilled in the art, as well as ratios for mixtures of more complex isomers, are also within the scope of the present invention.

[0086] This invention also includes isotopically labeled compounds (also called isotopic compounds), equivalent to the original compounds disclosed herein. However, in practice, it is common for one or more atoms to be replaced by atoms with different atomic weights or mass numbers. Examples of isotopes of compounds that can be included in this invention include hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, fluorine, and chlorine isotopes, respectively as follows: 2 H, 3 H, 13 C 11 C 14 C 15 N、 18 O、 17 O、 31 P, 32 P, 35 S, 18 F and 36Cl. The compounds of this invention, or enantiomers, diastereomers, isomers, or pharmaceutically acceptable salts or solvates, wherein the isotopes or other isotopic atoms of the aforementioned compounds are all within the scope of this invention. Certain isotopically labeled compounds of this invention, for example... 3 H and 14 Radioactive isotopes of carbon are also included, and are useful in tissue distribution experiments of drugs and substrates. Tritium, i.e. 3 H and carbon-14, i.e. 14 C, their preparation and detection are relatively easy. They are the preferred isotopes. In addition, heavier isotopes such as deuterium are used for substitution. 2 H, due to its excellent metabolic stability, offers advantages in certain therapies, such as increasing half-life or reducing dosage in vivo, and therefore may be preferred in some cases. Isotopically labeled compounds can be prepared using general methods, by replacing the non-isotopic reagent with an readily available isotopically labeled reagent, according to the scheme described in the examples.

[0087] To design the synthesis of a specific enantiomer of the compound of this invention, it can be prepared asymmetrically or derivatized with a chiral auxiliary. The resulting diastereomeric mixture is then separated, and the chiral auxiliary is removed to obtain the pure enantiomer. Alternatively, if the molecule contains a basic functional group, such as an amino acid, or an acidic functional group, such as a carboxyl group, it can be formed with a suitable optically active acid or base to form a diastereomer salt, which is then separated by conventional methods such as separation crystallization or chromatography to obtain the pure enantiomer.

[0088] As described herein, the compounds of this invention can be expanded with any number of substituents or functional groups. Generally, whether the term "substitution" appears before or after the term "optional," the general formula for substituents in the formulations of this invention refers to replacing a hydrogen radical with a substituent of a specified structure. When multiple positions in a particular structure are replaced by multiple specific substituents, each position of the substituent can be the same or different. The term "substitution" as used herein includes all permissible substitutions in organic compounds. In a broad sense, permissible substituents include acyclic, cyclic, branched-unbranched, carbocyclic, and heterocyclic, aromatic and non-aromatic organic compounds. In this invention, heteroatomic nitrogen may be supplemented with hydrogen substituents or any permissible organic compound described above to complete its valence state. Furthermore, this invention is not intended to limit permissible substituted organic compounds in any way. This invention considers the combination of substituents and variable groups to be beneficial in the treatment of diseases in the form of stable compounds. The term "stable" here refers to a compound that is stable enough to maintain the integrity of its structure when tested over a sufficiently long period of time, preferably remaining effective over a sufficiently long period of time, and is used here for the purposes described above.

[0089] The compounds involved in this application and their pharmaceutically acceptable salt metabolites, as well as prodrugs that can be converted in vivo into structures of the compounds involved in this application and their pharmaceutically acceptable salts, are also included in the claims of this application.

[0090] Preparation method

[0091] The preparation method of the compound of formula (I) of the present invention is described in more detail below, but these specific methods do not constitute any limitation on the present invention. The compounds of the present invention can also be conveniently prepared by optionally combining various synthetic methods described in this specification or known in the art, such combinations can be easily performed by those skilled in the art.

[0092] Typically, in the preparation process, each reaction is carried out under inert gas protection, in a suitable solvent, at room temperature to 90°C, and the reaction time is usually 2-24 hours.

[0093] Method 1:

[0094]

[0095] In Method 1, R1, R2, R3, R4, R5, and R6 have the definitions described in this invention. The method includes the following steps:

[0096] (i) In an organic solvent such as methanol, methyl azide reacts with the aldehyde group in compound 1-1 to generate compound 1-2; preferably, the reaction is carried out in the presence of a base, more preferably, the base is NaOMe (sodium methoxide).

[0097] (ii) Compounds 1-2 are refluxed in an organic solvent such as xylene to form compound 1-3;

[0098] (iii) In an inert solvent (such as DMF) under basic conditions, compounds 1-3 react with benzyl bromide derivatives to form compounds 1-4; preferably, the reaction is carried out in the presence of CsCO3;

[0099] (iv) In an organic solvent (such as a mixture of methanol and tetrahydrofuran), under alkaline conditions, the methyl carboxylate in compounds 1-4 is hydrolyzed to carboxylic acids to generate compounds 1-5; preferably, hydrolysis is performed in the presence of LiOH;

[0100] (v) In quinoline, compounds 1-5 react with copper powder under acidic conditions to generate compounds 1-6; preferably, the reaction is carried out in the presence of a catalyst (such as Cu);

[0101] (vi) In an organic solvent (such as a mixture of DMSO and methanol), under alkaline conditions and an atmosphere of carbon monoxide, compounds 1-6 are converted to compounds 1-7 via palladium catalysis; preferably, the palladium catalyst used is PdCl2dppf, and / or the reaction temperature is 75±5°C.

[0102] (vii) In an organic solvent (such as a mixture of methanol and tetrahydrofuran), under alkaline conditions, the methyl carboxylate in compound 7 is hydrolyzed to form carboxylic acids to generate compounds 1-8; preferably, hydrolysis is performed in the presence of LiOH;

[0103] (viii) In an inert solvent (such as DMF), compounds 1-8 condense with benzylamine to form compounds 1-9; preferably, the condensation occurs in the presence of HATU and DIEA;

[0104] (ix) In an inert solvent (such as a mixture of methanol and tetrahydrofuran), under alkaline conditions, the methyl carboxylate in compounds 1-9 is hydrolyzed to carboxylic acids to form compounds 1-10; preferably, hydrolysis is performed in the presence of LiOH.

[0105] In the above reaction steps, the reaction solvent, reaction temperature, reaction time, catalyst, etc., can be selected according to the specific reactants.

[0106] Pharmaceutical Compositions and Administration

[0107] Because the compounds of the present invention are excellent EP4 receptor antagonists, the compounds of the present invention and their various crystal forms, pharmaceutically acceptable inorganic or organic salts, hydrates, solvates, stereoisomers, isotopic compounds or prodrugs, and the pharmaceutical compositions of the present invention can be used for the treatment or prevention of EP4 receptor-related diseases such as prostaglandin E2 / EP4 receptor-mediated diseases. The pharmaceutical compositions of the present invention are used for the prevention and / or treatment of the following diseases: acute and chronic pain, inflammatory pain, inflammation-related disorders, osteoarthritis and rheumatoid arthritis, and cancer.

[0108] This invention includes a method for treating inflammatory diseases sensitive to nonsteroidal anti-inflammatory drugs (NSAIDs), the method comprising administering to a patient requiring such treatment a nontoxic, therapeutically effective amount of a compound of formula I. In this embodiment, the above method is included, wherein the patient is also at risk of thrombotic cardiovascular events and / or gastrointestinal ulcers / bleeding.

[0109] Another embodiment of the invention includes a method for treating a prostaglandin E2-mediated disease, which is advantageously treated by selectively antagonizing the activity of EP4 rather than by inhibiting the activity of COX-1 / COX-2, the method comprising administering a non-toxic, effective amount of the compound represented by Formula I to a patient requiring such treatment. This embodiment includes the above method, wherein the patient is also at risk of thrombotic cardiovascular events.

[0110] For example, but not limited to, the compounds described herein can be used in cancer immunotherapy targeting host immunosuppressive cells in the tumor microenvironment, which can be myeloid or lymphoid. In one embodiment, the compounds described herein can be used to treat patients with various tumor types, including those with high levels of myeloid infiltration. This level of myeloid infiltration can be determined, for example, based on the Cancer Genome Atlas (TCGA) and other sources. Such tumor types can also be identified based on protein or gene (e.g., mRNA) expression analysis.

[0111] Tumor types include, but are not limited to, pancreatic adenocarcinoma, clear cell renal cell carcinoma, squamous cell carcinoma of the head and neck (SCCHN), non-small cell lung cancer (NSCLC), colorectal cancer (CRC), hepatocellular carcinoma (HCC), serous epithelial ovarian cancer, cervical cancer, transitional cell bladder cancer, skin cancer, glioblastoma, renal cancer, prostate cancer, pancreatic cancer, and triple-negative breast cancer (TNBC).

[0112] The compounds of this invention can be used to treat or prevent tumor formation in subjects who require such treatment or prevention. Treatment includes partial or complete inhibition of tumor formation, spread, or metastasis, and partial or complete destruction of tumor cells. The term "prevention" includes complete prevention of the onset of clinically apparent tumor formation or prevention of the onset of a clinically apparent tumor-forming stage in an individual at risk. This definition is also intended to include prevention of the initiation of malignant cells or to stop or reverse the development of malignant pre-malignant cells into malignant cells. This includes prophylactic treatment for persons at risk of developing neoplasms. The term "subject" used for therapeutic purposes includes any human or mammalian subject suffering from any known tumor, and preferably a human subject. For preventative methods, the subject is any human or animal subject, and preferably a human subject at risk of developing a tumor. Subjects may be at risk due to exposure to carcinogens, genetic predisposition to tumors, etc.

[0113] The compound of formula (I) can be used in combination with other known drugs for treating or improving similar symptoms. When used in combination, the administration method and dosage of the original drug can remain unchanged, while the compound of formula I is taken simultaneously or subsequently. When the compound of formula I is taken concurrently with one or more other drugs, a pharmaceutical composition containing one or more known drugs and the compound of formula I is preferred. Drug combination also includes taking the compound of formula I with one or more other known drugs during overlapping time periods. When the compound of formula I is used in combination with one or more other drugs, the dosage of the compound of formula I or the known drug may be lower than the dosage of either drug alone. Antitumor activity of EP4 antagonists in various combinations with the following drugs: radiation; antibodies against cytotoxic T-lymphocyte antigen 4 (anti-CTLA4); antibodies against programmed death ligand 1 (anti-PDL1); antibodies against programmed cell death protein 1 (anti-PD1); and antimetabolites have been detected. The present invention also includes a method of treating cancer with an effective amount of the compound of the present invention or using an effective amount of the compound of the present invention in combination with an effective amount of the following substances: radiation; an antibody against cytotoxic T-lymphocyte antigen 4 (anti-CTLA4); an antibody against programmed death ligand 1 (anti-PDL1); an antibody against programmed cell death protein 1 (anti-PD1); an indoleamine-2,3-dioxygenase (IDO) inhibitor; a tryptophan-2,3-dioxygenase (TDO) inhibitor; and antimetabolites. These antibodies may be selected from, but are not limited to, MDX-010 (ipilimumab, Bristol-Myers Squibb), CP-675,206 (tremelimumab, Pfizer), MPDL 3280A (Roche), MDX-1106 (nivolumab, Bristol-Myers Squibb), labrolizumab (Merck), and pembrolizumab (Merck).

[0114] "Pharmaceutically acceptable carriers" refers to one or more compatible solid or liquid fillers or gelling substances that are suitable for human use and must have sufficient purity and sufficiently low toxicity. "Compatibility" here means that the components in the composition can be mixed with and with the compounds of the present invention without significantly reducing the efficacy of the compounds. Examples of pharmaceutically acceptable carriers include cellulose and its derivatives (such as sodium carboxymethyl cellulose, sodium ethyl cellulose, cellulose acetate, etc.), gelatin, talc, solid lubricants (such as stearic acid, magnesium stearate), calcium sulfate, vegetable oils (such as soybean oil, sesame oil, peanut oil, olive oil, etc.), polyols (such as propylene glycol, glycerin, mannitol, sorbitol, etc.), emulsifiers (such as... Wetting agents (such as sodium dodecyl sulfate), colorants, flavoring agents, stabilizers, antioxidants, preservatives, pyrogen-free water, etc.

[0115] "Pharmaceutically acceptable excipients" and "pharmaceutically acceptable carriers" refer to substances that facilitate the formulation and / or administration and / or absorption of the active agent by an individual and can be included in the compositions disclosed herein without causing significant adverse toxicological effects on that individual. Non-limiting examples of pharmaceutically acceptable carriers and excipients include water, NaCl, physiological saline solutions, lactated Ringer's solution, conventional sucrose, conventional glucose, binders, fillers, disintegrants, lubricants, coatings, sweeteners, flavorings, salt solutions (e.g., Ringer's solution), alcohols, oils, gelatin, carbohydrates such as lactose, amylose or starch, fatty acid esters, hydroxymethyl cellulose, polyvinylpyrrolidone, and pigments. Such formulations can be sterilized and, if desired, mixed with adjuvants such as lubricants, preservatives, stabilizers, wetting agents, emulsifiers, salts affecting osmotic pressure, buffers, colorants, and / or aromatic substances that will not harmfully react with or interfere with the activity of the compounds provided herein. Those skilled in the art will recognize that other pharmaceutical carriers and excipients are suitable for the disclosed compounds.

[0116] In some embodiments, the pharmaceutical compositions of the present invention may be in solid or liquid form.

[0117] Pharmaceuticals containing an active ingredient (i.e., compounds represented by Formula I) may be in suitable oral dosage forms, such as tablets, pills, lozenges, water-soluble or oily suspensions, dispersed latex powders or granules, emulsions, hard or soft capsules, or syrups or elixirs. Orally administered pharmaceuticals may be prepared according to known process methods of the pharmaceutical ingredient manufacturer. These compositions may include one or more of the following agents, such as sweeteners, flavoring agents, coloring agents, and protective agents, to provide an elegant and palatable pharmaceutical formulation. Tablets contain the active ingredient mixed with non-toxic, pharmaceutically acceptable excipients suitable for tablet production. Examples of these excipients include inert diluents such as calcium carbonate, sodium carbonate, lactose, calcium phosphate, or sodium phosphate; granulating agents, disintegrants such as corn starch or alginic acid; binding agents such as starch, gelatin, or gum arabic; and lubricants such as magnesium stearate, stearic acid, or talc. The tablet may be uncoated or coated to delay degradation and absorption in the gastrointestinal tract, thereby maintaining its activity over a longer period.

[0118] The pharmaceutical compositions of the present invention can be administered via parenteral, oral, buccal, sublingual, nasal, rectal, topical, or transdermal administration. Pharmaceutical compositions for oral administration are generally preferred.

[0119] Pharmaceutical compositions of the present invention suitable for oral administration will typically be discrete units in solid form, such as tablets, capsules, pouches, powders, granules, lozenges, patches, suppositories, pills, or in liquid form, such as liquid formulations, injectable or infusionable solutions or suspensions.

[0120] The precise amount of compound that provides a therapeutically effective dose to an individual will depend on the route of administration, the type and severity of the disease and / or condition, and individual characteristics such as general health, age, sex, weight, and tolerance to the drug. Those skilled in the art will be able to determine the appropriate dosage based on these and other factors. When administered in combination with other therapeutic agents, the “therapeutically effective amount” of any other therapeutic agent will depend on the type of drug used. Appropriate dosages are known for approved therapeutic agents and can be adjusted by those skilled in the art based on the individual’s condition, the type of condition being treated, and the amount of the compound of the invention used below, for example, the dosages reported in the literature and recommended in Physician's Desk Reference (57th edition, 2003).

[0121] In the pharmaceutical composition of the present invention, the content of the active ingredient is generally 0.000001-1 wt%, preferably 0.00001-1 wt%, and most preferably 0.0001-0.1 wt%.

[0122] Examples of subjects to which the pharmaceutical compositions or therapeutic agents of the present invention are administered include mammals (e.g., humans, mice, rats, hamsters, rabbits, cats, dogs, cattle, sheep, monkeys, etc.).

[0123] The present invention also provides a method for preparing a pharmaceutical composition, comprising the steps of: mixing a pharmaceutically acceptable carrier with a compound of general formula (I) or its crystal form, a pharmaceutically acceptable salt, a hydrate or a solvate of the present invention, thereby forming a pharmaceutical composition.

[0124] The present invention also provides a treatment method comprising the steps of: administering to a subject requiring treatment a compound of general formula (I) as described in the present invention, or a crystal form thereof, a pharmaceutically acceptable salt, hydrate or solvate thereof, or administering a pharmaceutical composition as described in the present invention for selectively inhibiting the EP4 receptor.

[0125] The present invention has the following main advantages:

[0126] (1) The compounds of the present invention have excellent inhibitory activity against the EP4 receptor and have better selective inhibitory activity against the EP4 receptor;

[0127] (2) The compounds of this invention have lower toxicity and side effects;

[0128] (3) The compounds of the present invention have better pharmacodynamics, pharmacokinetic properties and drug-likeness.

[0129] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions as described in Sambrook et al., Molecular Cloning: A Laboratory Manual (New York: Cold Spring Harbor Laboratory Press, 1989), or as recommended by the manufacturer. Unless otherwise stated, percentages and parts are by weight.

[0130] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0131] The structures of the compounds of the present invention were determined by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC-MS).

[0132] NMR was performed using Bruker AVANCE-400 and Bruker AVANCE-500 NMR spectrometers. The solvents used for the determination included deuterated dimethyl sulfoxide (DMSO-d6), deuterated acetone (CD3COCD3), deuterated chloroform (CDCl3), and deuterated methanol (CD3OD). Tetramethylsilane (TMS) was used as the internal standard. Chemical shifts were measured in parts per million (ppm).

[0133] Liquid chromatography-mass spectrometry (LC-MS) was performed using an Agilent 1260 mass spectrometer. HPLC determinations were performed using an Agilent 1100 high-performance chromatograph (Microsorb 5micron C18 100x 3.0 mm column).

[0134] Thin-layer chromatography (TLC) uses Qingdao GF254 silica gel plates, with a thickness of 0.15-0.20 mm for TLC and 0.4-0.5 mm for preparative TLC. Column chromatography typically uses Qingdao 200-300 mesh silica gel as the support.

[0135] The starting materials used in the embodiments of the present invention are all known and commercially available, or can be synthesized using or in accordance with literature reported in the field.

[0136] Unless otherwise specified, all reactions in this invention are carried out under the protection of a dry inert gas (such as nitrogen or argon) by continuous magnetic stirring, and the reaction temperature is [degrees Celsius].

[0137] The following abbreviations are used throughout this invention.

[0138] THF: Tetrahydrofuran; MeOH: Methanol; HCl: Hydrochloric acid; Pd(PPh3)4: Tetraphenylphosphine palladium; K2CO3: Potassium carbonate; AcOK: Potassium acetate; NaOH: Sodium hydroxide; H2O: Water; TEA: Triethylamine; DIEA: N,N-Diisopropylethylamine; DMF: N,N-Dimethylformamide; DMA: N,N-Dimethylacetamide; Py: Pyridine; DCE: 1,2-Dichloroethane; DMSO: Dimethyl sulfoxide; TFA: Trifluoroacetic acid; NaBH(AcO)3: Triacetylboronic acid Sodium chloride; Sn2(Bu-n)6: hexa-n-butyltin; AlCl3: aluminum trichloride; CuI: cuprous iodide; DPPA: diphenyl azidophosphate; BuOH: tert-butanol; Cs2CO3: cesium carbonate; K3PO4: potassium phosphate; BnBr: benzyl bromide; Pd2(dba)3: tris(dibenzylacetone)dipalladium; X-Phos: 2-dicyclohexylphospho-2,4,6-triisopropylbiphenyl; EA: ethyl acetate; NaHCO3: sodium bicarbonate; DIPEA: N,N-diisopropylethylamine; HBr: hydrogen bromide;

[0139] Example

[0140] Example 1: Synthesis of Compound 1

[0141]

[0142] Step 1: Synthesis of methyl 2-azido-3-(4-bromo-5-methylthiophen-2-yl)acrylate

[0143] Methyl azide acetate (8.3 g, 72.8 mmol) and 4-bromo-5-methylthiophene-2-carboxaldehyde (5 g, 24 mmol) were dissolved in 50 mL of methanol. A methanol solution of NaOMe (13.5 mL, 5.4 M) was added dropwise at -25 °C. The mixture was stirred at 0 °C for 2 h, and then 50 mL of ice water was added. The mixture was stirred and filtered. The filter cake was washed with water and dried. Methyl 2-azido-3-(4-bromo-5-methylthiophene-2-yl)acrylate (3.6 g, 49%) was obtained, which did not require purification and could be used in the next step.

[0144] Step 2: Synthesis of methyl 3-bromo-2-methyl-4H-thiophene[3,2-b]pyrrole-5-carboxylic acid

[0145] Within 10 minutes, the crude product (3.6 g) dissolved in xylene (50 mL) from the previous step was added dropwise to refluxed xylene (40 mL). After reflux for 20 minutes, the mixture was cooled to room temperature, concentrated, and the solvent was removed to obtain a solid crude product. The solid was dissolved, extracted, dried, and concentrated to give methyl 3-bromo-2-methyl-4H-thiophene[3,2-b]pyrrole-5-carboxylic acid (3.2 g, 98%), MS: m / z (ESI): 273.95 [M+H]. + .

[0146] Step 3: Synthesis of methyl 3-bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thieno[3,2-b]pyrrole-5-carboxylic acid

[0147] Methyl 3-bromo-2-methyl-4H-thiophene[3,2-b]pyrrole-5-carboxylate (2.5 g, 9.1 mmol), 4-(pentafluorothio)benzyl bromide (3.0 g, 10.1 mmol), and cesium carbonate (9.0 g, 27.5 mmol) were dissolved in DMF (20 mL) and stirred at room temperature for 4 hours. After the reaction was complete, the mixture was quenched with water, the organic phase was separated, washed with water, dried, and subjected to column chromatography (PE:EA = 5:1) to give methyl 3-bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-5-carboxylate (3.0 g, 90%) as a yellow solid. MS: m / z (ESI): 489.95 [M+H] + .

[0148] Step 4: Synthesis of 3-bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thieno[3,2-b]pyrrole-5-carboxylic acid

[0149] At room temperature, methyl 3-bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thieno[3,2-b]pyrrole-5-carboxylic acid (3.0 g, 6.1 mmol) was dissolved in 40 mL of 1:1 MeOH / THF solution. Then, 20 mL of H₂O and 404 mg (18.4 mmol) of lithium hydroxide were added. The mixture was stirred at 55 °C for 2 hours. The organic solvent was removed by concentration, and the pH was adjusted to 4-5 with citric acid aqueous solution. The solid was filtered, washed, and dried to obtain 3-bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thieno[3,2-b]pyrrole-5-carboxylic acid (3.0 g) as a yellow solid. MS: m / z (ESI): 475.93 [M+H] + .

[0150] Step 5: Synthesis of 3-bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole

[0151] 3-Bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-5-carboxylic acid (3.0 g, 6.3 mmol) was dissolved in 30 mL of quinoline, and then 2.0 g of copper powder was added. The mixture was reacted at 140 °C for 16 hours. After cooling to room temperature, the solution was acidified with 6N hydrochloric acid, extracted, washed with water, dried, and subjected to column chromatography (PE) to give 3-bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole (1.21 g, 44%) as a pale yellow solid. MS m / z (ESI): 431.94 [M+H] + .

[0152] Step 6: Synthesis of methyl 2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carboxylic acid ester

[0153] At room temperature, 0.7 g (1.85 mmol) of 3-bromo-2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole, 680 mg (0.83 mmol) of PdCl2dppf.CH2Cl2, and 374 mg (3.70 mmol) of triethylamine were dissolved in 20 mL of 1:1 dimethyl sulfoxide / methanol and heated overnight at 75 °C under CO (balloon pressure). After the reaction was complete, the mixture was quenched with water, extracted, washed with water, dried, and subjected to column chromatography (PE:EA = 2:1) to give methyl 2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carboxylic acid (0.4 g, 52%) as a yellow solid. MS m / z (ESI): 412.04 [M+H] + .

[0154] Step 7: Synthesis of 2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carboxylic acid

[0155] Methyl 2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carboxylic acid (0.4 g, 0.97 mmol) was dissolved in 15 mL of a 1:2 MeOH / THF solution at room temperature. Then, 5 mL of H₂O and 116 mg (0.85 mmol) of lithium hydroxide were added. The mixture was stirred at 55 °C for 2 hours. The organic solvent was removed by concentration, and the pH was adjusted to 4-5 with citric acid aqueous solution. The solid was filtered, washed, and dried to obtain 340 mg (85%) of 2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carboxylic acid as a yellow solid. MS m / z (ESI): 398.1 [M+H] + .

[0156] Step 8: Synthesis of methyl 4-(1-{[2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carbonyl]amino}-cyclopropyl)benzoate

[0157] At room temperature, 2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carboxylic acid (340 mg, 0.85 mmol), methyl 4-(1-aminocyclopropyl)benzoate (245 mg, 1.28 mmol), HATU (486 mg, 1.28 mmol), and DIEA (220 mg, 1.7 mmol) were dissolved in DMF (10 mL) and stirred at room temperature for 16 hours. After the reaction was completely quenched with water, extracted, washed with water, and dried, the solution was subjected to column chromatography (DCM:MeOH = 20:1) to give methyl 4-(1-{[2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carbonyl]amino}-cyclopropyl)benzoate (0.45 g, 92%) as a yellow solid. MS m / z(ESI): 571.1 [M+H] + .

[0158] Step 9: Synthesis of 4-(1-{[2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carbonyl]amino}-cyclopropyl)benzoic acid

[0159] At room temperature, methyl 4-(1-{[2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carbonyl]amino}-cyclopropyl)benzoate (0.45 g, 0.79 mmol) was dissolved in 30 mL of MeOH / THF in a 1:2 solution. Then, 5 mL of H2O and 190 mg, 7.91 mmol of lithium hydroxide were added. The mixture was stirred at 55 °C for 2 hours. The organic solvent was removed by concentration. The pH was adjusted to 4-5 with citric acid aqueous solution. The solid was filtered, washed, and dried to obtain a crude product. The crude product was slurried with 10 mL of diethyl ether to obtain 4-(1-{[2-methyl-4-(4-(pentafluorothio)benzyl)-4H-thiophene[3,2-b]pyrrole-3-carbonyl]amino}-cyclopropyl)benzoic acid (compound 1) (340 mg, 85%) as a yellow solid. MS m / z (ESI): 557.1 [M+H] + .

[0160] 1H NMR (400MHz): δ11.12(s,1H), 8.98(s,1H), 7.69-7.74(m,4H), 7.14(d,2H),7.06(s, 1H), 6.97(d,2H), 6.38(s,2H), 5.43(s,2H), 2.48(s,3H), 1.17(m,2H), 0.96(m,2H).

[0161] Example 2

[0162] Other compounds in Table 1 were prepared using a method similar to that in Example 1.

[0163]

[0164]

[0165] Example 1 of bioactivity test:

[0166] (a) Assay of radioligand EP4 receptor binding:

[0167] Experimental Methods: Flpin-CHO-EP4 cells (8000 cells / well) were seeded into 384-well plates (6007680-50, PE) using test buffer (1X HBSS + 20mM HEPES + 0.1% BSA + 500μM IBMX). 8X compound working solution was prepared using test buffer. 2.5μL of 8X compound working solution was added to each well of the cell plate according to the plate map, and incubated at 37℃ for 10 min. 8X PGE2 (400nM) was prepared using test buffer. 2.5μL of 8X PGE2 was added to each well of the cell plate, and incubated at 37℃ for 30 min. Eu-cAMP tracer (1 / 50) was diluted with lysis buffer, and 10μL was added to each well of the detection plate. Ulight-anti-cAMP (1 / 150) was diluted with lysis buffer, and 10μL was added to each well of the detection plate. The plates were incubated at room temperature for 1 h. The 665nm and 615nm wavelength signal values ​​were read using an Envision 2105 reader. The results are shown in Table 2.

[0168] Table 2:

[0169]

[0170]

[0171] Tests have shown that the compounds of this invention exhibit excellent binding activity to the EP4 receptor and excellent EP4 receptor inhibitory ability.

[0172] (b) Determination of the PK of the compounds of the present invention:

[0173] The pharmacokinetics of the compounds were investigated in male Han Wistar rats. The compounds were administered intravenously and orally (n=3 for each dose route), and samples were collected at multiple time points post-administration. Plasma extracts were quantitatively analyzed using specific and sensitive LC-MS / MS bioanalytical methods.

[0174] Tests have shown that the compounds of this invention possess good pharmacodynamic and pharmacokinetic properties.

[0175] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A compound represented by Formula 1, or a pharmaceutically acceptable salt thereof, 2. A pharmaceutical composition comprising the compound of claim 1, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent.

3. Use of the compound of claim 1, or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition of claim 2, for the manufacture of a medicament for the treatment or prevention of a disease associated with EP4 receptor.

4. Use according to claim 3, characterized in that, The disease associated with EP4 receptor is selected from the group consisting of acute and chronic pain, osteoarthritis, rheumatoid arthritis, and cancer.

5. Use of the compound of claim 1, or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition of claim 2, for the manufacture of a medicament for inhibiting EP4 receptor.

6. Use of the compound of claim 1, or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition of claim 2, for the manufacture of an EP4 receptor antagonist.

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