Morphinan type compound as well as preparation method, composition and application thereof

Abstract

The invention relates to a morphinan type compound as well as a preparation method, a composition and application thereof. Specifically disclosed is a compound I or a pharmaceutically acceptable salt thereof. The morphinan type compound provided by the invention has one or more of the following effects and advantages: (1) the morphinan type compound is relatively high in binding affinity with an opioid receptor; (2) the compound has an obvious agonistic effect on KOR and MOR; (3) the selectivity to a kappa receptor is good; and (4) the ointment has a good treatment effect on inflammatory pain (for example, the ointment takes effect quickly or has an obvious pain effect).

Description

Technical Field

[0001] This invention relates to a morphinan-type compound, its preparation method, its composition, and its application. Background Technology

[0002] Opioid receptors are widely distributed in the nervous system and participate in various pathophysiological processes such as pain, inflammation, and itching through G protein-coupled mechanisms. They mainly include three types: muopioid receptor (MOR), delta-opioid receptor (DOR), and kappaopioid receptor (KOR). The specific distribution of kappaopioid receptors and their intradermal opioid peptides in the nervous system, especially the spinal cord, suggests that kappaopioid receptors play a role in pain regulation (see *Anatomy of CNS opioid redeptors*, 2004:9(1):24-9). Kappaopioid agonists have analgesic effects while having low addictive potential and do not cause constipation or respiratory depression.

[0003] Etazocine is also a selective KOR agonist with strong analgesic effects and lower rates of dependence, drowsiness, and respiratory depression. Difelikefalin is a selective KOR agonist that acts on the peripheral nervous system and certain immune cells. The FDA has approved this drug in the United States for the treatment of moderate to severe pruritus associated with chronic kidney disease in adults undergoing hemodialysis. It has also demonstrated some long-acting analgesic activity in clinical trials.

[0004] Patent application PCT / US2020 / 025717 discloses a class of morphinan compounds and their uses as κ receptor agonists. However, further development is needed of compounds with high affinity for κ receptors, good agonistic activity, and good analgesic activity to achieve better therapeutic effects and meet market demands. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiency of the limited variety of κ receptor agonists in the prior art. Therefore, a morphinan-type compound, its preparation method, its composition, and its application are provided. The morphinan-type compound of the present invention has one or more of the following advantages: (1) high affinity for opioid receptors; (2) significant agonistic effect on KOR and MOR; (3) good selectivity for κ receptors; (4) good therapeutic effect on inflammatory pain (e.g., rapid onset of action or significant analgesic effect).

[0006] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0007] This invention provides a compound I or a pharmaceutically acceptable salt thereof:

[0008] ;

[0009] in,

[0010] n is 1, 2, or 3;

[0011] R 1 It is a halogen or a C1-C6 alkyl group substituted with one or more halogens;

[0012] R 2 It is hydroxyl, C1-C6 alkyl or -O-C1-C6 alkyl;

[0013] m is 0, 1, or 2;

[0014] Each R 3 Each is independently a hydroxyl group, a C1-C6 alkyl group, or an -O-C1-C6 alkyl group;

[0015] R 4 It can be hydrogen, halogen, hydroxyl, C1-C6 alkyl, or -O-C1-C6 alkyl;

[0016] R 5 It is a hydroxyl group, a C1-C6 alkyl group, an -O-C1-C6 alkyl group, or a compound containing one or more R groups. 5-1 Substituted C1-C6 alkyl groups;

[0017] R 5-1 It is a C3-C6 cycloalkyl group or a C3-C6 cycloalkyl group substituted with one or more hydroxyl groups;

[0018] p is 0, 1, 2 or 3;

[0019] Each R 6 Each can be independently a hydroxyl, cyano, -C(=O)NH2, halogen, amino, nitro, thiol, C1-C6 alkyl, -O-C1-C6 alkyl, or -O-C6-C 10 Aryl.

[0020] In some implementation schemes, R 1 In this context, the halogen is fluorine, chlorine, bromine, or iodine; preferably chlorine.

[0021] In some implementation schemes, R 1 In the embodiment, the C1-C6 alkyl group substituted with one or more halogens is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl.

[0022] In some embodiments, the halogen in the C1-C6 alkyl group substituted with one or more halogens is fluorine, chlorine, bromine, or iodine; preferably fluorine.

[0023] In some embodiments, the C1-C6 alkyl group substituted with one or more halogens is trifluoromethyl.

[0024] In some implementation schemes, R 2 In the C1-C6 alkyl group and the -O-C1-C6 alkyl group, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl.

[0025] In some implementation schemes, R 3 In the C1-C6 alkyl group and the -O-C1-C6 alkyl group, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl.

[0026] In some implementation schemes, R 4 In the C1-C6 alkyl group and the -O-C1-C6 alkyl group, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl.

[0027] In some implementation schemes, R 4 In this context, the halogen is fluorine, chlorine, bromine, or iodine.

[0028] In some implementation schemes, R 5 In the C1-C6 alkyl group, the C1-C6 alkyl group in the -O-C1-C6 alkyl group and the C1-C6 alkyl group with one or more R 5-1 The C1-C6 alkyl groups in the substituted C1-C6 alkyl groups are each independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl, preferably methyl.

[0029] In some implementation schemes, R 5-1 In the C3-C6 cycloalkyl group and the C3-C6 cycloalkyl group substituted with one or more hydroxyl groups, the C3-C6 cycloalkyl group is independently cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, preferably cyclopropyl.

[0030] In some implementation schemes, R 6 In the C1-C6 alkyl and -O-C1-C6 alkyl, the C1-C6 alkyl is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl.

[0031] In some implementation schemes, R 6 In the context, the -O-C6-C 10 C6-C in aryl 10 The aryl group is either phenyl or naphthyl.

[0032] In some implementations, n is 1 or 2.

[0033] In some implementation schemes, R 1 It is a halogen.

[0034] In some implementation schemes, R 1 It is located adjacent to O in the furan ring.

[0035] In some implementation schemes, R 2 It is a C1-C6 alkyl group.

[0036] In some implementations, m is 0.

[0037] In some implementation schemes, R 4 It is a hydroxyl group.

[0038] In some implementation schemes, R 5 For one or more R 5-1 Substituted C1-C6 alkyl groups.

[0039] In some implementation schemes, R 5-1 It is a C3-C6 cycloalkyl group.

[0040] In some implementations, p is 1.

[0041] In some implementation schemes, R 6 It is a hydroxyl group.

[0042] In some implementation schemes, R 1 It is chlorine.

[0043] In some implementation schemes, R 2 It is a methyl group.

[0044] In some implementation schemes, R 5 for .

[0045] In some embodiments, compound I is compound I-1 or compound I-2:

[0046] ;

[0047] Where, n, R 1 R 2 R 4 R 5 and R 6 The definition is as described above;

[0048] Better place,

[0049] n is 1 or 2;

[0050] R 1 It is a halogen;

[0051] R 1 It is located adjacent to O in the furan ring.

[0052] In some embodiments, compound I is any of the following compounds:

[0053] .

[0054] The present invention provides a method for preparing the above-mentioned compound I, which includes the following steps: in a solvent, in the presence of a base and a condensing agent, compound II and compound III undergo an amide condensation reaction as shown below to obtain compound I;

[0055] ;

[0056] Where, n, R 1 R 2 m, R 3 R 4 R 5 p and R 6 The definition is as stated in the previous item.

[0057] In some embodiments, the solvent is a conventional solvent used in the art for carrying out such amide condensation reactions, preferably an amide solvent, and more preferably N,N-dimethylformamide (DMF).

[0058] In some embodiments, the molar volume ratio of compound II to the solvent may be 0.1-0.2 mol / L; preferably 0.14 mol / L.

[0059] In some embodiments, the base is a conventional base used in the art for carrying out such amide condensation reactions, preferably an organic base, and more preferably triethylamine.

[0060] In some embodiments, the molar ratio of compound II to triethylamine may be 1:(2-5); preferably 1:3.

[0061] In some embodiments, the condensing agent is a conventional condensing agent in the art for carrying out such amide condensation reactions, preferably N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (HATU).

[0062] In some embodiments, the molar ratio of compound II to the condensing agent may be 1:(0.9-1.3); preferably 1:1.1.

[0063] In some embodiments, the molar ratio of compound II to compound III may be 1:(0.9-1.3); preferably 1:1.1.

[0064] In some embodiments, the reaction temperature of the amide condensation reaction can be conventional in the art, preferably room temperature, for example 15-35°C; more preferably 20-25°C.

[0065] In some embodiments, the reaction time of the amide condensation reaction is related to the reaction scale. Generally, the reaction endpoint is defined as the disappearance of the starting material or the cessation of product production.

[0066] In some embodiments, the amide condensation reaction further includes the following post-processing step: after the reaction is completed, the mixture is washed, dried, and subjected to column chromatography to obtain compound I.

[0067] This invention provides a compound III':

[0068] ;

[0069] Where n and R 1 The definition is as described above;

[0070] R 7 It is OH or C1-C6 alkyl.

[0071] This invention provides a compound III':

[0072] ;

[0073] Where n and R 1 The definition is as described above;

[0074] R 7 It can be OH, C1-C6 alkyl, or -O-C1-C6 alkyl.

[0075] In some embodiments, compound III' is any of the following compounds:

[0076] , , .

[0077] This invention provides a pharmaceutical composition comprising:

[0078] (1) Compound I as described above, or a pharmaceutically acceptable salt thereof, and

[0079] (2) Pharmaceutically acceptable excipients.

[0080] The present invention provides the use of compound I as described above or a pharmaceutically acceptable salt thereof, or the above pharmaceutical composition, in the preparation of a medicament for treating a disease or condition.

[0081] In some embodiments, the disease or condition is pain or itching; the pain is preferably postoperative pain, cancer pain, neuropathic pain, inflammatory pain (e.g., osteoarthritis pain), or traumatic pain; the itching is preferably inflammatory itching, uremic itching, cholestatic itching, diabetic itching, or itching associated with chronic kidney disease.

[0082] The present invention provides the use of compound I as described above or a pharmaceutically acceptable salt thereof, or the above pharmaceutical composition, in the preparation of diseases or conditions related to the κ receptor.

[0083] In some embodiments, the disease or symptom is pain or itching; the pain and itching are preferably as described above.

[0084] The present invention provides the use of compound I as described above or a pharmaceutically acceptable salt thereof, or the above pharmaceutical composition, in the preparation of a κ receptor agonist.

[0085] In some embodiments, the κ receptor agonist can be used in mammalian organisms; it can also be used in vitro, primarily for experimental purposes, such as providing a standard or control sample for comparison, or preparing a kit according to conventional methods in the art to provide rapid detection of the effect of κ receptor agonism.

[0086] Terminology Explanation

[0087] In this invention, the term "pharmaceutically acceptable salt" refers to a salt obtained by reacting a compound with a pharmaceutically acceptable acid or base. When a compound contains a relatively acidic functional group, a base addition salt can be obtained by contacting the compound with a sufficient amount of a pharmaceutically acceptable base in a suitable inert solvent. When a compound contains a relatively basic functional group, an acid addition salt can be obtained by contacting the compound with a sufficient amount of a pharmaceutically acceptable acid in a suitable inert solvent. See Handbook of Pharmaceutical Salts: Properties, Selection, and Use (P. Heinrich Stahl, Camille G. Wermuth, 2011, 2nd Revised Edition) for details.

[0088] In this invention, the term "pharmaceuticalally acceptable excipient" refers to all substances contained in a pharmaceutical preparation other than the active pharmaceutical ingredient, and is generally divided into two main categories: excipients and additives. For details, please refer to the *Pharmacopoeia of the People's Republic of China (2020 Edition)* and *Handbook of Pharmaceutical Excipients* (Paul J Sheskey, Bruno CHancock, Gary P Moss, David J Goldfarb, 2020, 9th Edition).

[0089] In this invention, the "" in the structural segment This means that the structural segment is connected to the rest of the molecule through this bond. For example, It refers to cyclopropyl.

[0090] In this invention, the "-" at the end of a group indicates that the group is connected to the rest of the molecule through that site. For example, -OH refers to a hydroxyl group.

[0091] In this invention, the term "one or more" refers to 1, 2, 3, 4 or 5, for example, 1, 2 or 3.

[0092] In this invention, the term "halogen" refers to fluorine, chlorine, bromine, or iodine.

[0093] In this invention, the term "alkyl" refers to a saturated monovalent hydrocarbon group that has a specified number of carbon atoms (e.g., C1-C6), is straight-chain or branched. Alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, etc.

[0094] In this invention, the term "alkoxy" refers to the group R. Y -O-,R Y The definition is the same as the term "alkyl". Alkoxy groups include, but are not limited to: methoxy, ethoxy, n-propoxy, isopropoxy, etc.

[0095] In this invention, the term "cycloalkyl" refers to a cyclic, saturated monovalent hydrocarbon group having a specified number of carbon atoms (e.g., C3-C6). Cycloalkyl groups include, but are not limited to: , , wait.

[0096] In this invention, the term "aryl" refers to an aryl group having a specified number of carbon atoms (e.g., C6-C). 10Aromatic groups are cyclic, unsaturated monovalent hydrocarbon groups, which can be monocyclic or polycyclic (e.g., two or three). When polycyclic, the monocyclic rings share two atoms and one bond, and each ring is aromatic. The aryl group is connected to the rest of the molecule through an aromatic ring. Aromatic groups include, but are not limited to, phenyl and naphthyl groups.

[0097] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0098] The reagents and raw materials used in this invention are all commercially available.

[0099] The positive and progressive effects of the present invention are as follows: the morphinoid compounds of the present invention have one or more of the following advantages: (1) high affinity for opioid receptors; (2) significant agonistic effects on KOR and MOR; (3) good selectivity for κ receptors; (4) good therapeutic effect on inflammatory pain (e.g., rapid onset of action or significant analgesic effect); (5) can be used to prepare drugs for relieving or treating pain, providing a new strategy for the development of analgesic drugs. Detailed Implementation

[0100] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0101] Unless otherwise specified, the experimental methods described in the following examples are conventional methods. Unless otherwise specified, all reagents used in the experimental methods are commercially available.

[0102] 1 ¹H NMR data were collected and recorded at 600 MHz using a Bruker Ultrashield 600 NMR spectrometer, with DMSO-d6 as the solvent and TMS (δ=0) as the internal standard to report chemical shift δ values ​​(ppm). Mass spectrometry was acquired and recorded using a Waters ACQUITY LC-MS system. Column: ACQUITY UPLC BEH C8, 50 mm × 2.1 mm, 1.7 μm (20180306-C8-17); Mobile phase A: 0.1% formic acid / water; Mobile phase B: 0.1% formic acid / acetonitrile; Detector wavelength: UV-210nm+ full wavelength (190 nm~400 nm); QDa: Cone voltage: 15 V for positive scan, 15 V for negative scan; Capillary voltage: +0.8 kV, -0.8 kV.

[0103] Washing procedure:

[0104]

[0105] Example 1 Synthesis of T01-5

[0106]

[0107] In a single-necked flask, 3-furancarbaldehyde (1.0 eq, 30.0 g), pyridine (15 mL), and malonic acid (1.0 eq, 32.5 g) were added sequentially, stirred until dissolved, fitted with a reflux condenser, and heated in an oil bath at 95 °C for 2 h. The reaction was monitored by TLC until complete. After concentration, column chromatography yielded 43.5 g of a yellow oily substance, T01-1. MS m / z = 139.02 [M+H] + .

[0108] Weigh 1.0 eq (20.0 g) of T01-1, add 200 mL of analytical grade ethanol, and then add 47.2 g of trimethylchlorosilane. Stir at room temperature. Monitor the reaction by TLC until complete, and then evaporate and concentrate the reaction solution. Column chromatography yields 19.6 g of a pale yellow oil, T01-2. MS m / z = 167.01 [M+H] + .

[0109] Weigh out 1.0 eq (0.80 g) of oily substance T01-2, dissolve and stir in 8 mL of analytical grade DMF. Add a DMF solution of N-chlorosuccinimide (NCS, 1.1 eq, 0.65 g) to the reaction flask. Incubate at 25 °C. Monitor the reaction for completeness by TLC. Add purified water, extract twice with ethyl acetate, wash twice with saturated sodium bicarbonate solution, dry, and evaporate to dryness. Column chromatography yields 0.29 g of oily substance T01-3. MS m / z = 201.07 [M+H] + .

[0110] The three-necked flask was evacuated under nitrogen protection. 15 mL of anhydrous DMSO was added. Sodium hydride (60%, 3.0 eq, 0.43 g) was weighed and added to the reaction flask, then stirred. Trimethyl sulfoxide (3.0 eq, 3.9 g) was then weighed and added to the reaction flask, stirred until dissolved. Oily substance T01-2 (1.0 eq, 1.0 g) was weighed and dissolved in 10 mL of anhydrous DMSO. After the solid in the first reaction flask dissolved, the solution was added dropwise to the second reaction flask, and the mixture was heated in an oil bath at 50°C. LC-MS was monitored until the reaction was complete. The mixture was quenched with 25 mL of purified water, and then extracted three times with ethyl acetate. The extracts were combined and washed three times with water. The organic phase was dried over anhydrous sodium sulfate, and evaporated to dryness to obtain 0.68 g of a yellow, transparent oily substance T01-4. MS m / z = 215.07 [M+H] + .

[0111] 1H NMR (600 MHz, DMSO-d6) δ 7.60 (t, J = 2.1 Hz, 1H), 6.44(s, 1H), 2.13(d, J = 7.2 Hz, 1H), 2.04 – 1.95(m, 2H), 1.92(dd, J = 8.8, 5.1 Hz, 1H),1.22–1.20(m, 3H), 0.86(dt, J = 8.0, 4.2 Hz, 2H).

[0112] Weigh 1.0 eq (0.1 g) of T01-4, dissolve and stir in ethanol, adjust the pH to 12-13 with 1 M sodium hydroxide solution, stir at room temperature in the dark, monitor the reaction until complete by TLC, adjust the pH to 2-3 with 1 M HCl, extract with ethyl acetate to obtain 57 mg of white solid T01-5. MS m / z = 185.01 [MH] - .

[0113] 1 H NMR(400 MHz, DMSO-d6) δ 12.39 (s, 1H), 7.61(d,J = 2.2 Hz, 1H), 6.44 (d,J = 2.2 Hz, 1H), 2.11–2.05(m, 1H), 1.81–1.75(m, 1H), 1.41–1.32(m,1H), 1.23(ddd,J = 8.4, 6.3, 4.3 Hz, 1H).

[0114] Example 2 Synthesis of T01-7

[0115]

[0116] Weigh naltrexone (1.0 eq, 36.6 g), add 750 mL of toluene and stir to dissolve. Add N-methylbenzylamine (1.5 eq, 19.5 g) and p-toluenesulfonic acid (0.01 eq, 0.18 g), heat to reflux, and react for 3 days. Monitor the reaction for completeness using LCMS. Concentrate to dryness under reduced pressure, add 500 mL of ethanol and stir until homogeneous. Add sodium cyanoborohydride (1.5 eq, 10.1 g) to the solution and stir at room temperature for 1 day. Monitor the reaction for completeness using LCMS. Add water and stir at room temperature for 1 day. Filter, extract the filtrate three times with ethyl acetate, combine the organic phases, dry to dryness with anhydrous sodium sulfate, and evaporate to dryness. Silica gel column chromatography yields 21.2 g of white solid T01-6. ESI-MS m / z: 447.35 [M+H] + .

[0117] T01-6 (1 eq, 0.5 g) was dissolved in 10 mL of acetic acid, and 12 mg of 10% palladium / carbon was added. The mixture was stirred at 25 °C under a hydrogen atmosphere, and the reaction was monitored for completeness by LCMS. The mixture was filtered through diatomaceous earth, and the filtrate was concentrated under reduced pressure. 3.5 mL of water was added, and the pH was adjusted to 9.5 with ammonia. The mixture was extracted twice with dichloromethane, and the organic phases were combined, dried, and concentrated to give 0.38 g of pale yellow solid T01-7. ESI-MS m / z: 357.27 [M+H].

[0118] Example 3 Synthesis of compound T01

[0119]

[0120] Weigh out T01-5 (1.1 eq, 115 mg), add 4 mL of N,N-dimethylformamide and stir to dissolve. Then add N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (HATU, 1.1 eq, 235 mg), T01-7 (1.0 eq, 200 mg), and triethylamine (3.0 eq, 170 mg) sequentially. React at room temperature until complete. Add ethyl acetate, wash with water, dry, and column chromatography to obtain 192 mg of pale yellow solid T01. ESI-MS m / z = 525.22 [M+H] + .

[0121] 1 H NMR (600 MHz, DMSO-d6) δ 9.74-9.11 (m,1H), 7.90-7.32 (m,1H), 6.77-5.83 (m,3H), 5.05-4.66 (m,1H), 4.19-3.60 (m,2H), 3.39-3.27 (m,2H), 3.21-2.78(m,6H), 2.49-2.34 (m,2H), 2.30-1.96 (m,2H), 1.96-1.78 (m,1H), 1.78-1.69 (m,2H), 1.51-1.33 (m,3H), 1.32-1.16 (m,1H), 1.15-0.97 (m,2H), 0.71-0.66 (m,1H),0.61-0.56 m,1H), 0.53-0.48 (m,1H), 0.43-0.39 (m,1H).

[0122] Example 4 Synthesis of compound T02

[0123]

[0124] The three-necked flask was evacuated under nitrogen protection. 15 mL of anhydrous DMSO was added. Sodium hydride (60%, 3.0 eq, 0.43 g) was weighed and added to the reaction flask, then stirred. Trimethyl sulfoxide (3.0 eq, 3.9 g) was then weighed and added to the reaction flask, stirred until dissolved. Oily substance T01-2 (1.0 eq, 1.0 g) was weighed and dissolved in 10 mL of anhydrous DMSO. After the solid in the first reaction flask dissolved, the solution was added dropwise to the second reaction flask, and the mixture was heated in an oil bath at 50°C. LC-MS was monitored until the reaction was complete. The mixture was quenched with 25 mL of purified water, and then extracted three times with ethyl acetate. The extracts were combined and washed three times with water. The organic phase was dried over anhydrous sodium sulfate, and evaporated to dryness to obtain 0.68 g of a yellow, transparent oily substance T02-1. MS m / z = 181.10 [M+H] + .

[0125] Weigh 1.0 eq (1.0 g) of oily substance T02-1, dissolve and stir in 8 mL of analytical grade DMF, and place in a constant temperature reaction bath at 0-5℃. Slowly add a DMF solution of N-chlorosuccinimide (NCS, 2.2 eq, 1.6 g) dropwise to the reaction flask, and stir at low temperature for 24 h. Monitor the reaction by TLC until complete. Add purified water, extract twice with ethyl acetate, wash the organic phase twice with saturated sodium bicarbonate solution, dry, and evaporate to dryness. Column chromatography yields 0.63 g of oily substance T02-2. MS m / z = 249.02 [M+H] + .

[0126] 1 H NMR (600 MHz, DMSO-d6) δ 6.56 (d, J = 2.0 Hz, 1H), 4.10 (q, J =7.2 Hz, 2H), 2.11 (dddd, J = 8.8, 6.4, 4.2, 1.8 Hz, 1H), 2.00 – 1.94 (m, 1H), 1.20 (td, J = 7.1, 1.8 Hz, 3H), 0.83 (q, J = 8.8, 6.3 Hz, 2H).

[0127] Weigh 1.0 eq (0.1 g) of T02-2, dissolve and stir in ethanol, adjust the pH to 12-13 with 1 M sodium hydroxide solution, stir at room temperature in the dark, monitor the reaction for completeness by TLC, adjust the pH to 2-3 with 1 M HCl, and extract with ethyl acetate to obtain 68 mg of white solid T02-3. MS m / z = 219.15 [MH] - .

[0128] 1H NMR (600 MHz, DMSO-d6) δ 12.46 (s, 1H), 6.54 (s, 1H), 2.06 (ddd, J = 9.1, 6.3, 4.1 Hz, 1H), 1.82 (ddd, J = 8.5, 5.3, 4.1 Hz, 1H), 1.36 (ddd, J =9.4, 5.3, 4.3 Hz, 1H), 1.24 (ddd, J = 8.5, 6.3, 4.3 Hz, 1H).

[0129] Weigh out T02-3 (1.1 eq, 136 mg), add 4 mL of N,N-dimethylformamide and stir to dissolve. Then add N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (HATU, 1.1 eq, 235 mg), T01-7 (1.0 eq, 200 mg), and triethylamine (3.0 eq, 170 mg) sequentially. React at room temperature until complete. Add ethyl acetate, wash with water, dry, and precipitate by column chromatography to obtain 215 mg of pale yellow solid T02. MS m / z = 559.45 [M+H] + .

[0130] 1 H NMR (600 MHz, DMSO-d6) δ 9.59-9.09 (m,1H), 6.74-5.90 (m,4H), 5.03-4.74 (m,1H), 4.17-3.59 (m,2H), 3.35-3.26 (m,2H), 3.22-2.81 (m,6H), 2.67-2.51(m,1H), 2.47-2.36 (m,1H), 2.33-2.00 (m,2H), 1.97-1.65 (m,2H), 1.54-1.30 (m,3H), 1.29-1.16 (m,1H), 1.17-0.99 (m,2H), 0.70-0.65 (m,1H), 0.62-0.55 (m,1H),0.53-0.50 (m,1H), 0.42-0.38 (m,1H).

[0131] Example 6 Opioid receptor binding assay

[0132] Reagents: DOR (PerkinElmer, RBHODM400UA); KOR (Perkin Elmer, ES-541-M400UA); MOR (Perkin Elmer, ES-542-M400UA); [ 3H]DADLE (Perkin Elmer, NET1130);[ 3 H]U-69,593 (Perkin Elmer, NET952); [ 3 [H]DAMGO (Perkin Elmer, NET902250UC); Naltrexone hydrochloride (Sigma, Bachem H-4044); DAMGO (MCE, 78123-71-4); ULTIMA GOLD (Perkin Elmer, 77-16061); Polyethyleneimine (Sigma, 408727); HEPES (Sigma, 7365-45-9); BSA (Sigma, 9048-46-8); Tris-base (Sigma, 77-86-1).

[0133] Membrane stock solutions: 50 mM Hepes (pH 7.4) and 10 mM MgCl2 plus 1 mM EDTA for DOR; 50 mM Tris (pH 7.4) and 5 mM MgCl2 for KOR; 50 mM HEPES (pH 7.4) and 0.025% BSA for MOR.

[0134] 0.5% polyethyleneimine solution: Take 0.5 mL of polyethyleneimine and place it in a volumetric flask. Add water to make up to 100 mL and store at 4℃ for later use.

[0135] According to the plate diagram, compounds of different concentrations were transferred to 96-well plates. 100 μL of membrane stock solution and 5 μL of cpds (1% DMSO) were added to each well, and the plates were incubated at 500 rpm for 5 min at room temperature. Then, 300 μL of assay buffer containing opioid receptors was added to each well, and the plates were incubated at 500 rpm for 5 min at room temperature. Afterwards, 100 μL of […] was added to each well. 3 H]DADLE (final concentration 0.5 nM) / [ 3 H]U-69,593 (final concentration 1.5 nM) / [ 3[H]DAMGO (final concentration 1.0 nM) was incubated at room temperature with stirring at 500 rpm for 5 min, followed by incubation at 27°C for 1 h. Then, Unifilter-96GF / C plates were immersed in 0.5% polyethyleneimine solution per well and incubated at 4°C for 1 h at room temperature. The reaction mixture was filtered through the plates using a collector, and each plate was washed four times with cold wash buffer (50 mM Tris·HCl, pH 7.4). The plates were then dried at 55°C for 10 min. After drying, 40 μL of ULTIMA GOLD was added to each well, and radioactivity was counted using a Perkin Elmer MicroBeta2 counter.

[0136] In the presence of 50-100 times excess cold ligand, specific binding was determined by subtracting the binding CPM value. Data were fitted using a nonlinear curve fitting procedure based on saturation analysis in Prism. Inhibition was calculated using the following equation:

[0137] % Inhibition = (1 - (Measurement well - Average LC) / (Average HC - Average LC)) * 100%

[0138] The combined data were analyzed using GraphPad Prism 5.0, and IC was generated by nonlinear regression from the dose-response curves. 50 The data was fitted using the model “log(inhibitor) vs. response – variable slope”. The data is shown in Table 1.

[0139] Table 1 Binding Affinity IC 50

[0140]

[0141] "-" indicates that it was not measured.

[0142] Conclusion: Compounds T01 and T02 have high affinity for opioid receptors and exhibit good selectivity.

[0143] Example 7: cAMP detection of opioid receptor agonistic activity

[0144] When DOR, KOR, or MOR bind to agonists, they can regulate the activity of adenylate cyclase, thereby altering intracellular cAMP levels. Cells stably expressing MOR, KOR, or DOR are first stimulated with compounds, followed by induction of intracellular cAMP production with forskolin. Compounds with opioid receptor agonist activity inhibit the effect of forskolin on cAMP production. Changes in intracellular cAMP levels can be detected using a cAMP assay kit to reflect the agonistic effect of the compounds on opioid receptors.

[0145] Reagents: Fetal bovine serum (AUS Gene X, FBS500-S); DMEM medium (Gibco, 11965-092); F12K medium (Hyclone, SH30526.01); penicillin-antibody (Gibco, 15140122); Hygromycin B (Invivogen, ant-hg-5); Forskolin (Selleck, S2449); 7.5% BSA (Perkin Elmer, CR84-100); cAMP assay kit (Perkin Elmer, TRF0263); IBMX (Sigma, I5879); HEPES buffer (Gibco, 15630080).

[0146] HEK293 cells expressing high levels of DOR and KOR were cultured in DMEM complete medium containing 10% FBS, 1% penicillin-antibody antibiotics, and 200 μg / mL hygromycin B. CHO cells expressing high levels of MOR were cultured in F12K complete medium containing 10% FBS, 1% penicillin-antibody antibiotics, and 200 μg / mL hygromycin B. Cells in the logarithmic growth phase were collected by centrifugation and counted, and added to 384-well plates at 20,000 cells / well. Different concentrations of the test compound were added to the wells, and the plates were incubated at 37°C for 10 min. Then, 2.5 μL of Forskolin (final concentration 8 μM) was added, and the plates were incubated at 37°C for 30 min. After the reaction, 10 μL of Eu-cAMPtracer working solution and 10 μL of Ulight-anti-cAMP working solution were added to each well, and the plates were incubated at room temperature in the dark for 1 h. The 384-well plates were analyzed using an Envision 2015 multi-functional microplate reader.

[0147] Using DADLE, DynorphinA1-10, and Endomorphin 1 as positive control agents, the activation rate (%Acivity) under different concentration conditions was calculated using the following formula.

[0148] % Activity = (Signalcmpd-SignalAve_VC) / (SignalAve_PC-SignalAve_VC)×100.

[0149] Plot the compound effect curve and calculate the compound's EC using the following formula. 50 value,

[0150] Y=Bottom + (Top-Bottom) / (1+10^((LogEC 50 -X)*HillSlope))

[0151] X: Logarithm of compound concentration; Y: Activation rate.

[0152] Table 2 Agonist Activity EC 50

[0153]

[0154] "-" indicates that it was not measured.

[0155] Conclusion: The compounds of this invention have significant agonistic effects on KOR and MOR compared to positive control drugs, and their agonistic effect on KOR is comparable to that of DynorphinA1-10.

[0156] The comparative example demonstrates the effect of formalin-induced inflammatory pain in rats.

[0157] The preparation method of the comparative compound 5a is described in patent PCT / US2020 / 025717.

[0158] A diluted formalin solution is injected subcutaneously into the hind paw of a rat using a microinjection needle, creating a continuous noxious stimulus that elicits spontaneous pain behavior in the animal. The pain occurs in two phases: an acute phase and a chronic phase. The degree of pain can be assessed by recording the number of times the rat lifts or licks its paw using a voluntary movement analyzer.

[0159] Experimental materials:

[0160] SD rats, weighing 220-240 g, were purchased from Nansilek Jingda Experimental Animal Co., Ltd., license number SCXK (Xiang) 2019-0004; 0.9% sodium chloride injection was purchased from Shandong Kelun Pharmaceutical Co., Ltd., batch number C23053303A; DMSO was purchased from Sigma-Aldrich, batch number 1003544872; formalin was purchased from Sigma, batch number 252549; electronic scale was purchased from Shanghai Ranhao Electronics Co., Ltd., batch number JCS-51002C; electronic balance was purchased from Ohaus Instruments (Changzhou), batch number PX124ZH; voluntary motion analyzer was purchased from Yichang Renfu Pharmaceutical Co., Ltd., batch number NA; vortex mixer was purchased from Shanghai Chitang Electronics Co., Ltd., batch number XW-80A; T01 and T02 are compounds obtained in the embodiments of this invention.

[0161] Experimental preparation:

[0162] After 2 days of acclimatization feeding, SD rats were transferred from the feeding area to the laboratory every morning. A training urine pad was placed on the experimental table, and a transparent white cylinder was placed on the training urine pad. Each rat was weighed and then placed in the test transparent white cylinder to acclimatize to the test environment for about 1 hour. This process was repeated for at least 3 consecutive days.

[0163] Experimental steps:

[0164] After acclimatizing to the experimental environment for 3 days, rats weighing 220-240 g were numbered at the base of their tails; those not reaching the target weight continued to be fed until they did. Thirty minutes before the formal test, a metal plate was attached to the left hind paw of each rat, and the rats were placed in transparent white cylinders for acclimatization. The test sample or control sample was administered 15 minutes before the test. Fifteen minutes later, 50 μL of 2% formalin was subcutaneously injected into the dorsal side of the left hind paw to establish the model (the blank control group did not receive formalin). Subsequently, the animals were placed in a spontaneous movement analyzer, which automatically recorded the number of times the rats withdrew, raised, or licked their paws, and the data from 0-60 minutes after formalin injection were statistically analyzed.

[0165] Testing indicators:

[0166] After subcutaneous injection of 2% formalin into the dorsum of the foot of rats, the rats were placed in a test chamber to record and analyze the number of movements (number of times the injected foot was lifted and licked) from 0 to 60 minutes after the injection of formalin solution, including the early acute phase (phase I: 0-9 minutes) and the late tense phase (phase II: 10-60 minutes).

[0167] Calculate MPE% (Maximum Possible Effect, expressed as a percentage).

[0168]

[0169] Notes: ① MPE% for each group was calculated based on a standard of 100% for the sham group and 0% for the vehicle group. ② The number of movements in the sham group was subtracted to eliminate the influence of background noise on the experiment. ③ Sham represents the average value of the sham group; Vehicle-Sham represents the average value of the vehicle group minus Sham.

[0170] Experimental data and processing:

[0171] The results and data from the measurements and observations were entered into an Excel spreadsheet and statistical analysis was performed.

[0172] Each indicator is expressed as the standard error of the mean. Data for each group were statistically analyzed and plotted using GraphPad prim 8 software. One-way ANOVA was used to compare whether there were statistical differences between the groups. The t-test was used to compare the two groups, and p < 0.05 was considered statistically significant.

[0173] Table 3. Record of Experimental Phenomena

[0174]

[0175] Analysis of experimental results:

[0176] In a rat formalin model, under the condition of subcutaneous injection (30 μg / kg) 15 min before modeling, compound T01 and the control compound 5a had comparable analgesic activity; meanwhile, compound T02 showed a significant tendency to have analgesic activity against 2% formalin-induced inflammatory pain in mice, and was significantly stronger than the control compound 5a. The experimental results are shown in Table 4.

[0177] Table 4. Maximum possible analgesic effect 0-60 min after modeling.

[0178]

[0179] The foregoing description describes specific embodiments of the present invention. However, those skilled in the art should understand that modifications or improvements can be made to the present invention. For example, the Cl atom on the furan ring in the two molecules of the present invention can be replaced by Br, F, or other atoms or groups, which is obvious to those skilled in the art. All modifications and improvements made without departing from the principles and essence of the present invention fall within the scope of protection of the present invention.

Claims

1. A compound I or a pharmaceutically acceptable salt thereof: ； in, n is 1, 2, or 3; R 1 It is a halogen or a C1-C6 alkyl group substituted with one or more halogens; R 2 It is hydroxyl, C1-C6 alkyl or -O-C1-C6 alkyl; m is 0, 1, or 2; Each R 3 Each is independently a hydroxyl group, a C1-C6 alkyl group, or an -O-C1-C6 alkyl group; R 4 It can be hydrogen, halogen, hydroxyl, C1-C6 alkyl, or -O-C1-C6 alkyl; R 5 It is a hydroxyl group, a C1-C6 alkyl group, an -O-C1-C6 alkyl group, or a compound containing one or more R groups. 5-1 Substituted C1-C6 alkyl groups; R 5-1 It is a C3-C6 cycloalkyl group or a C3-C6 cycloalkyl group substituted with one or more hydroxyl groups; p is 0, 1, 2 or 3; Each R 6 Each can be independently a hydroxyl, cyano, -C(=O)NH2, halogen, amino, nitro, thiol, C1-C6 alkyl, -O-C1-C6 alkyl, or -O-C6-C 10 Aryl.

2. The compound I as claimed in claim 1, or a pharmaceutically acceptable salt thereof, characterized in that, It satisfies one or more of the following conditions: (1) R 1 In this context, the halogen is fluorine, chlorine, bromine, or iodine; preferably chlorine. (2) R 1 In this context, the C1-C6 alkyl group substituted with one or more halogens is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl, preferably methyl; (3) R 1 In this context, the halogen in the C1-C6 alkyl group substituted with one or more halogens is fluorine, chlorine, bromine, or iodine; preferably fluorine; more preferably, the C1-C6 alkyl group substituted with one or more halogens is trifluoromethyl. (4) R 2 In the C1-C6 alkyl group and the -O-C1-C6 alkyl group, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl; (5) R 3 In the C1-C6 alkyl group and the -O-C1-C6 alkyl group, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl; (6) R 4 In the C1-C6 alkyl group and the -O-C1-C6 alkyl group, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl, preferably methyl; (7) R 4 In this context, the halogen is fluorine, chlorine, bromine, or iodine; (8) R 5 In the C1-C6 alkyl group, the C1-C6 alkyl group in the -O-C1-C6 alkyl group and the C1-C6 alkyl group with one or more R 5-1 The C1-C6 alkyl groups that are substituted are each independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl, preferably methyl; (9) R 5-1 In this context, the C3-C6 cycloalkyl group and the C3-C6 cycloalkyl group substituted with one or more hydroxyl groups are each independently cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, preferably cyclopropyl; (10) R 6 In the C1-C6 alkyl group and the -O-C1-C6 alkyl group, the C1-C6 alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl; and (11) R 6 In the context, the -O-C6-C 10 C6-C in aryl 10 The aryl group is either phenyl or naphthyl.

3. The compound I as claimed in claim 1, or a pharmaceutically acceptable salt thereof, characterized in that, It satisfies one or more of the following conditions: (1) n is 1 or 2; (2) R 1 It is a halogen; (3) R 1 Located adjacent to O in the furan ring; (4) R 2 It is a C1-C6 alkyl group; (5) m is 0; (6) R 4 It is a hydroxyl group; (7) R 5 For one or more R 5-1 Substituted C1-C6 alkyl groups; (8) R 5-1 It is a C3-C6 cycloalkyl group; (8) p is 1; and (9) R 6 It is a hydroxyl group.

4. The compound I as described in claim 3, or a pharmaceutically acceptable salt thereof, characterized in that, It satisfies one or more of the following conditions: (1) R 1 It is chlorine; (2) R 2 It is methyl; (3) R 5 for .

5. The compound I as claimed in claim 1, or a pharmaceutically acceptable salt thereof, characterized in that, The compound I is either compound I-1 or compound I-2: ； Where, n, R 1 R 2 R 4 R 5 and R 6 The definition is as described in claim 1; Better place, n is 1 or 2; R 1 It is a halogen; R 1 It is located adjacent to O in the furan ring.

6. The compound I as claimed in claim 3, or a pharmaceutically acceptable salt thereof, characterized in that, Compound I is any of the following compounds: 。 7. A method for preparing compound I according to any one of claims 1-6, comprising the following steps: in a solvent, in the presence of a base and a condensing agent, compound II and compound III undergo an amide condensation reaction as shown below to obtain compound I; ； in, n, R 1 R 2 m, R 3 R 4 R 5 p and R 6 The definition is as described in any one of claims 1-6.

8. The method for preparing compound I according to claim 7, characterized in that, It satisfies one or more of the following conditions: (1) The solvent is an amide solvent, and the preferred amide solvent is N,N-dimethylformamide; (2) The molar volume ratio of compound II to the solvent is 0.1-0.2 mol / L; preferably 0.14 mol / L; (3) The base is an organic base, and the organic base is preferably triethylamine; (4) The molar ratio of compound II to triethylamine is 1:(2-5); preferably 1:3; (5) The condensing agent is N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea; (6) The molar ratio of compound II to the condensing agent is 1:(0.9-1.3); preferably 1:1.1; (7) The molar ratio of compound II to compound III is 1:(0.9-1.3); preferably 1:1.1; (8) The reaction temperature of the amide condensation reaction is 15-35°C; more preferably 20-25°C; and (9) The amide condensation reaction further includes the following post-processing steps: after the reaction is completed, the mixture is washed, dried, and subjected to column chromatography to obtain compound I.

9. A compound III': ； in, n and R 1 The definition is as described in any one of claims 1-6; R 7 It can be OH, C1-C6 alkyl, or -O-C1-C6 alkyl; Better place, The compound III' is any one of the following compounds: 、 、 。 10. A pharmaceutical composition comprising: (1) Compound I or a pharmaceutically acceptable salt thereof as described in any one of claims 1-6, and (2) Pharmaceutically acceptable excipients.

11. The use of compound I as described in any one of claims 1-6 or a pharmaceutically acceptable salt thereof, or the use of a pharmaceutical composition as described in claim 10, in the preparation of a medicament for treating a disease or condition; The disease or symptom may be pain or itching; the pain is preferably postoperative pain, cancer-related pain, neuropathic pain, inflammatory pain, or traumatic pain; the inflammatory pain is more preferably osteoarthritis pain; The pruritus is preferably inflammatory pruritus, uremic pruritus, cholestatic pruritus, diabetic pruritus, or pruritus associated with chronic kidney disease.

12. The use of compound I as described in any one of claims 1-6 or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition as described in claim 10, in the preparation of a disease or condition related to the κ receptor; The disease or symptom is pain or itching; the pain and itching are as described in claim 11.

13. The use of compound I as described in any one of claims 1-6 or a pharmaceutically acceptable salt thereof, or the use of the pharmaceutical composition as described in claim 10, in the preparation of a κ receptor agonist.

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