Compound with synergistic analgesic effect as well as pharmaceutical composition, preparation method and application thereof

Abstract

The invention discloses a small molecular twin drug compound with a synergistic analgesic effect and a pharmaceutical composition, a preparation method and application thereof. The twin drug molecule is formed by connecting a drug A and a drug B through a covalent bond, the drug A is nefopam, and the drug B is gamma-aminobutyric acid (GABA) and analogues thereof and comprises gabapentin, pregabalin, GABA, melogabalin and crigabalin. The analgesic effect of the composition is superior to that of combined administration and single administration, and the composition can obviously improve various acute and chronic inflammation pains and can relieve paclitaxel-induced peripheral neuralgia; the anti-inflammatory activity is higher than that of combined use and single drug, so that the compound has the potential of treating pain, inflammation and inflammatory pain related diseases; the interaction among the medicines can be effectively reduced, and the medication compliance of a patient is improved.

Description

Technical Field

[0001] The present invention relates to a compound with synergistic analgesic effect and a pharmaceutical composition, a preparation method and use thereof, and in particular to a small molecule twin drug compound with synergistic analgesic effect and a pharmaceutical composition, a preparation method and use thereof. Background Art

[0002] Pain seriously affects the quality of life of patients, so it is of great significance to actively and effectively treat pain. Nefopam is a new type of non-opioid, non-steroidal analgesic that is unique in both chemistry and pharmacology and has nothing to do with any currently known analgesics. There is no definite authoritative explanation for the analgesic mechanism of Nefopam so far, but existing studies have shown that Nefopam mainly acts on the pain transmission pathway in the central nervous system. Most researchers believe that Nefopam is similar to triple receptor (5-hydroxytryptamine, norepinephrine and dopamine) reuptake inhibitors and anticonvulsants, inhibiting the uptake of 5-hydroxytryptamine, norepinephrine and dopamine by synaptosomes, increasing the inhibitory force of 5-hydroxytryptamine and norepinephrine descending pathways, and regulating calcium and sodium ion channels to act on glutamate pathways, thereby reducing the activation of postsynaptic glutamate receptors, such as NMDA receptors, and exerting analgesic effects.

[0003] GABA is the most important and abundant inhibitory neurotransmitter in the human central nervous system. It plays an important role in central hyperexcitability associated with nerve injury and acts on inhibitory synapses in the brain by binding to specific transmembrane receptors in the presynaptic and postsynaptic plasma membranes. It has been reported that an increase in the concentration of GABA in the spinal cord causes analgesia, while a decrease in the concentration of GABA causes neuropathic pain. Studies have shown that exogenous GABA can attenuate the response of pain-excitatory neurons in the nucleus accumbens of normal rats to noxious stimuli and has a GABA receptor-mediated analgesia, suggesting that GABA receptors are involved in regulating the activity of the nucleus accumbens together with other transmitters. In addition, in a paclitaxel-induced neuropathic pain model, GABA administration reversed the excitability of rats with neuropathic pain in electrophysiological recordings. These results suggest that GABA plays an important role in the regulation of pain responses.

[0004] Gabapentin, pregabalin, melogabalin, and clegabalin are GABA analogs that were originally used as anticonvulsants and have now become first-line drugs for the treatment of neuropathic pain. Gabapentin, pregabalin, melogabalin, and clegabalin act on presynaptic voltage-gated Ca 2+ Channel alpha 2 δ 1 Subunits reduce Ca 2+Intravenous influx of gabapentin, thereby inhibiting the release of neurotransmitters (such as glutamate and norepinephrine) and reducing the excitability of neurons. However, only some patients achieved pain relief after treatment with these drugs. In addition, gabapentin, pregabalin, melogabalin and cligabalin also have a series of side effects, such as shortness of breath and ataxia. Studies have shown that the toxic side effects of such drugs can be reduced and the efficacy can be improved by combining drugs.

[0005] Summary of the invention

[0006] Purpose of the invention: The first purpose of the present invention is to provide a twin-drug small molecule compound with synergistic analgesic effect, the second purpose is to provide a pharmaceutical composition containing the compound, the third purpose is to provide a method for preparing the compound, and the fourth purpose is to provide a use of the compound and its pharmaceutical composition.

[0007] Technical solution: The chemical structure of the compound with synergistic analgesic effect described in the present invention is as follows:

[0008]

[0009] in, A structural fragment selected from the chemical structure of gabapentin, pregabalin, γ-aminobutyric acid, melogabalin, and cligabalin except for the hydrogen on the carboxyl group;

[0010] X is selected from halogen or an acid radical of any of the following acids: carbonic acid, sulfuric acid, phosphoric acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, citric acid, malic acid, tartaric acid, lactic acid, pyruvic acid, acetic acid, maleic acid, succinic acid, fumaric acid, salicylic acid, phenylacetic acid, mandelic acid, ferulic acid;

[0011] m is selected from 0, 1, and 2.

[0012] Preferably, in the chemical structure, Selected from

[0013] X is selected from F, Cl, Br, I;

[0014] m is selected from 0 and 1.

[0015] Preferably, the compound of the present invention is selected from any one of the following compounds:

[0016]

[0017] The present invention adopts a "multimodal analgesia" strategy to prepare Nefopam into twin drugs through covalent bonds with γ-aminobutyric acid (GABA) and its analogs (gabapentin, pregabalin, melogabalin or clegabalin). The synthesized twin drugs enter the body and release Nefopam and gabapentin, pregabalin, GABA, melogabalin or clegabalin through the Hofmann elimination and hydrolysis process, and produce synergistic analgesic effects through multiple analgesic mechanisms to obtain better analgesic effects, reduce dose-related side effects, and better meet clinical medication needs. Therefore, the twin drugs of the analgesic drug Nefopam and gabapentin, pregabalin, GABA, melogabalin or clegabalin have broad application prospects for the treatment of pain.

[0018] The pharmaceutical composition of the present invention contains the compound of the present invention and a pharmaceutically acceptable carrier.

[0019] Preferably, the pharmaceutically acceptable carrier can be an adjuvant widely used in the field of drug production. The adjuvant is mainly used to provide a safe, stable and functional pharmaceutical composition, and can also provide a method to dissolve the active ingredient at a desired rate after the subject receives the administration, or promote the effective absorption of the active ingredient after the subject receives the composition. The pharmaceutical adjuvant can be an inert filler, or provide a certain function, such as stabilizing the overall pH value of the composition or preventing the degradation of the active ingredient of the composition. The pharmaceutical adjuvant can include one or more of the following adjuvants: adhesives, suspending agents, emulsifiers, diluents, fillers, granulating agents, adhesives, disintegrants, lubricants, anti-adhesive agents, glidants, wetting agents, gelling agents, absorption delay agents, dissolution inhibitors, enhancers, adsorbents, buffers, chelating agents, preservatives, colorants, flavoring agents and sweeteners.

[0020] The pharmaceutical composition of the present invention can be prepared according to the disclosed content using any method known to those skilled in the art, such as conventional mixing, dissolving, granulating, emulsifying, grinding, encapsulating, embedding or lyophilizing processes.

[0021] The pharmaceutical composition of the present invention can be administered in any form, including injection (intravenous), mucosal, oral (solid and liquid preparations), inhalation, ocular, rectal, topical or parenteral (infusion, injection, implantation, subcutaneous, intravenous, intraarterial, intramuscular) administration. The pharmaceutical composition of the present invention can also be a controlled release or sustained release dosage form (e.g., liposomes or microspheres). Examples of solid oral preparations include, but are not limited to, powders, capsules, caplets, soft capsules, and tablets. Examples of liquid preparations for oral or mucosal administration include, but are not limited to, suspensions, emulsions, elixirs, and solutions. Examples of topical preparations include, but are not limited to, emulsions, gels, ointments, creams, patches, pastes, foams, lotions, drops, or serum preparations. Examples of preparations for parenteral administration include, but are not limited to, solutions for injection, dry powder preparations that can be dissolved or suspended in a pharmaceutically acceptable carrier, suspensions for injection, and emulsions for injection. Examples of other suitable formulations of the pharmaceutical composition include, but are not limited to, eye drops and other ophthalmic preparations; aerosols, such as nasal sprays or inhalers; liquid dosage forms suitable for parenteral administration; suppositories and lozenges.

[0022] The preparation method of the compound of the present invention comprises the following steps:

[0023]

[0024] (1) protecting the amino group in the structure of gabapentin, pregabalin, γ-aminobutyric acid, melogabalin or cligabalin to obtain intermediate I;

[0025] (2) Using an alkaline reagent to dissociate Nefopam hydrochloride into Nefopam, and reacting the free Nefopam with the intermediate The intermediate II is obtained by heating the reaction in a reaction solvent;

[0026] (3) subjecting the intermediate I obtained in step (1) to a condensation reaction with the intermediate II obtained in step (2) in the presence of a catalyst to obtain an intermediate III;

[0027] (4) removing the protecting group of the intermediate III obtained in step (3) under acidic, alkaline or neutral conditions to obtain the compound;

[0028] Where R 1 is selected from Boc, Cbz, Fomc, Alloc protecting groups, m, The definition of is as mentioned above.

[0029] Preferably, the amino protecting agent in step (1) is selected from di-tert-butyl dicarbonate (Boc 2O), benzyloxycarbonyl succinimide (Cbz-Cl), 9-fluorenylmethyl chloroformate (Fmoc-Cl) or allyl chloroformate (Alloc-Cl), the molar ratio of gabapentin, pregabalin, γ-aminobutyric acid, melogababalin or cligabalin to the amino protecting agent is 1: (1-10).

[0030] Preferably, the alkaline reagent in step (2) is selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, sodium bicarbonate, potassium bicarbonate, the reaction solvent is selected from acetonitrile, acetone, tetrahydrofuran, N,N-diformylformamide or N,N-diformylacetamide, nefopam and the intermediate The molar ratio is 1:(2~10).

[0031] Preferably, the catalyst described in step (3) is selected from 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI), 4-dimethylaminopyridine (DMAP), N,N'-dicyclohexylcarbodiimide (DCC), N,N'-diisopropylcarbodiimide (DIC), benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate (HBTU), 6-chlorobenzotriazole-1,1,3,3-tetramethyluronium hexafluorophosphate (HCTU) or 2-(1H-benzotriazol-L-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU), the molar ratio between intermediate I, intermediate II and catalyst is 1:(1-3):(0.01-10), and the reaction solvent is selected from dichloromethane, acetonitrile, acetone or tetrahydrofuran.

[0032] Preferably, the acidic, alkaline or neutral conditions in step (4) are selected from the conditions in the presence of ethyl acetate hydrochloric acid gas, trifluoroacetic acid, tetraethylammonium fluoride, tetramethylammonium fluoride, triethylamine, trimethylsilyl iodide or pyridine.

[0033] The compound or its pharmaceutical composition described in the present invention is used to prepare drugs for preventing and / or treating pain and nervous system diseases.

[0034] Preferably, the drug is a drug for preventing and / or treating acute pain, chronic pain, neuropathic pain, inflammatory pain, nociceptive pain, cancer pain, hyperalgesia or visceral pain.

[0035] Preferably, the drug is a drug for preventing and / or treating epilepsy, anxiety, depression, personality disorder, cognitive disorder, affective disorder, neurodegenerative disease, convulsive disease, schizophrenia, insomnia or restless legs syndrome.

[0036] Preferably, the drug has a dose-dependent analgesic effect.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0038] The present invention utilizes medicinal chemistry to connect nefopam and gamma-aminobutyric acid (GABA) and its analogs through covalent bonds, and finally obtains a new molecular entity with high analgesic activity. The analgesic efficacy is better than that of combined administration and single drug, and can not only significantly improve various acute and chronic inflammatory pains, but also relieve paclitaxel-induced peripheral neuropathy; and has higher anti-inflammatory activity than combined administration and single drug. Since treating inflammation is a feasible method for improving pain, the compounds designed by the present invention have the potential to treat pain, inflammation and inflammatory pain-related diseases; in addition, the interactions between drugs can be effectively reduced, and the compliance of patients with medication can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of compound 3;

[0040] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of compound 4;

[0041] Figure 3 is the carbon NMR spectrum of compound 3;

[0042] Figure 4 is the carbon NMR spectrum of compound 4;

[0043] Figure 5 Schematic diagram of the analgesic effect of Nefopam in the carrageenan-induced inflammatory pain model, where A is the analgesic time-effect curve of Nefopam in carrageenan-treated mice, B is the time-effect relationship represented by the AUC graph, and C is the ED of Nefopam in carrageenan-induced inflammatory pain mice. 50 value;

[0044] Figure 6 Figure 1 is a schematic diagram of the analgesic effect of nefopam in the osteoarthritis pain model induced by iodoacetic acid, where A is the analgesic time-effect curve of nefopam in mice treated with iodoacetic acid, B is the time-effect relationship represented by the AUC graph, and C is the ED of nefopam in mice with osteoarthritis pain induced by iodoacetic acid. 50 value;

[0045] Figure 7 Schematic diagram of the analgesic effect of Nefopam in the paclitaxel-induced neuropathic pain model, where A is the analgesic time-effect curve of Nefopam in paclitaxel-treated mice, B is the time-effect relationship represented by the AUC graph, and C is the ED of Nefopam in paclitaxel-induced neuropathic pain mice. 50 value;

[0046] Figure 8Schematic diagram of the analgesic effect of pregabalin / gabapentin in the carrageenan-induced inflammatory pain model, where A and C are the analgesic time-effect curves of pregabalin / gabapentin in carrageenan-treated mice, B and D are the time-effect relationships of pregabalin / gabapentin represented by AUC graphs, and E and F are the ED of pregabalin / gabapentin in carrageenan-induced inflammatory pain mice 50 value;

[0047] Fig. 9 Schematic diagram of the analgesic effect of pregabalin / gabapentin in the iodoacetic acid-induced osteoarthritis pain model, where A and C are the analgesic time-effect curves of pregabalin / gabapentin in mice treated with iodoacetic acid, B and D are the time-effect relationships of pregabalin / gabapentin represented by AUC graphs, and E and F are the ED of pregabalin / gabapentin in mice with iodoacetic acid-induced osteoarthritis pain. 50 value;

[0048] Fig.10 Schematic diagram of the analgesic effect of pregabalin / gabapentin in the paclitaxel-induced neuropathic pain model, where A and C are the analgesic time-effect curves of pregabalin / gabapentin in paclitaxel-treated mice, B and D are the time-effect relationships of pregabalin / gabapentin represented by AUC graphs, and E and F are the ED of pregabalin / gabapentin in paclitaxel-induced neuropathic pain mice 50 value;

[0049] Fig.11 Schematic diagram of the analgesic effect of compound 3 and compound 4 in the carrageenan-induced inflammatory pain model, wherein A and C are the analgesic time-effect curves of compound 3 and compound 4 in carrageenan-treated mice, B and D are the time-effect relationships of compound 3 and compound 4 represented by AUC graphs, and E and F are the ED of compound 3 and compound 4 in carrageenan-induced inflammatory pain mice 50 value;

[0050] Fig.12 Schematic diagram of the analgesic effect of compound 3 and compound 4 in the osteoarthritis pain model induced by iodoacetic acid, wherein A and C are the analgesic time-effect curves of compound 3 and compound 4 in mice treated with iodoacetic acid, B and D are the time-effect relationships of compound 3 and compound 4 represented by AUC graphs, and E and F are the ED of compound 3 and compound 4 in mice with osteoarthritis pain induced by iodoacetic acid. 50 value;

[0051] Fig.13Schematic diagram of the analgesic effect of compound 3 and compound 4 in the paclitaxel-induced neuropathic pain model, wherein A and C are the analgesic time-effect curves of compound 3 and compound 4 in paclitaxel-treated mice, B and D are the time-effect relationships of compound 3 and compound 4 represented by AUC graphs, and E and F are the ED of compound 3 and compound 4 in paclitaxel-induced neuropathic pain mice 50 value;

[0052] Fig.14 Schematic diagram of the motor coordination of compound 3 and compound 4 in the rotarod test. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below in conjunction with embodiments.

[0054] The structures of the compounds of the examples were determined by nuclear magnetic resonance (NMR) and / or mass spectrometry (MS). NMR shifts (δ) are given in ppm. NMR measurements were performed using a Bruker AVANCE III HD 500 NMR spectrometer, and the solvent used was deuterated dimethyl sulfoxide (DMSO-d 6 ), deuterated chloroform (CDCl 3 ) The internal standard was tetramethylsilane (TMS).

[0055] MS was measured using an Agilent 1260HPLC-6520Accurate-Mass Q-Tof mass spectrometer under the following test conditions: electrospray ionization source (ESI) and positive ion mode.

[0056] The thin layer chromatography silica gel plate uses Yantai Huanghai HSGF254 or Qingdao GF254 silica gel plate. The silica gel plate used in thin layer chromatography (TLC) adopts a specification of 0.15-0.2 mm, and the specification used for thin layer chromatography separation and purification products is 0.4-0.5 mm.

[0057] Silica gel column chromatography generally uses Yantai Huanghai Silica Gel 200-300 mesh silica gel as the carrier.

[0058] Unless otherwise specified in the examples, the reaction temperature is room temperature, 20 to 30°C;

[0059] The progress of the reactions in the examples was monitored by thin layer chromatography (TLC).

[0060] Example 1: Synthesis of 5-(2-(((S)-3-(aminomethyl)-5-methylhexanoyl)oxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazine-5-bromide hydrochloride (Compound 1)

[0061] The synthetic route is as follows:

[0062]

[0063] Step 1: Synthesis of 5-(2-hydroxyethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide (1A)

[0064] In a 100 mL round-bottom flask, 10 mL of acetonitrile and nefopam (5.0 g, 20 mmol, 1.0 eq) were added, and 2-bromoethanol (5.0 g, 40 mmol, 2.0 eq) was added under stirring. The mixture was stirred at 70 °C and monitored by TLC. After 2 hours, the nefopam reaction was complete. The reaction solution was cooled to room temperature, and the excess solvent was removed by rotary evaporator. 60 mL of ethyl acetate was added and stirred for 1 hour, and then filtered and dried to obtain 1A as a light yellow solid of 6.5 g, with a yield of 85.5%. (+)-ESI-MS: m / z 298.1812 (calcd. 298.1802 for C 19 H 24 NO 2 + [M-Br] + ).

[0065] Step 2: Synthesis of (S)-3-(((tert-butyloxycarbonyl)amino)methyl)-5-methylhexanoic acid (1B)

[0066] In a 100 mL round-bottom flask, pregabalin (1.6 g, 10 mmol, 1.0 eq) and 1 mol / L sodium hydroxide aqueous solution (0.8 g, 20 mmol, 2.0 eq) were added, and a mixed solution of di-tert-butyl dicarbonate (2.65 g, 12 mmol, 1.2 eq) and 25 mL of dioxane was added dropwise under stirring. After stirring at room temperature for 2 hours, TLC monitored that pregabalin had reacted completely. The reaction solution was cooled to room temperature, and dichloromethane (3 × 15 mL) was added for extraction. The aqueous phases were combined and NaHCO was added. 3 The pH was adjusted to 4-5, and dichloromethane (3×20 mL) was added for re-extraction. The organic layers were combined, washed with 15 mL of saturated brine, dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain 1B as a white solid powder (2.11 g) with a yield of 81.1%. 1H NMR(500MHz,Chloroform-d)δ4.80(t,J=6.5Hz,1H),3.25(dt,J=14.0,5.3Hz,1H),3.08(dt,J=14.0,6.9Hz,1H),2.40-2.23(m,2H),2.14(dp,J =19.3,8.2,6.4Hz,1H),1.68(dh,J=13.1,6.6Hz,1H),1.47(d,J=12.7Hz,9H),1.23-1.11(m,2H),0.92(dd,J=8.8,6.6Hz,6H).(+)-ESI-MS:m / z 260.1872(calcd.260.1856for C 13 H 26 NO 4 + [M+H] + ).

[0067] Step 3: Synthesis of 5-(2-(((S)-3-(((tert-butyloxycarbonyl)amino)methyl)-5-methylhexanoyl)oxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide (1C)

[0068] In a 100 mL round-bottom flask, 20 mL of dichloromethane, 1A (0.76 g, 2 mmol, 1.0 eq), 1B (0.62 g, 2.4 mmol, 1.2 eq), DMAP (0.024 g, 0.2 mmol, 0.1 eq) were added, and EDCI (0.46 g, 2.4 mmol, 1.2 eq) was added after stirring, and the reaction was carried out at room temperature. The reaction process was monitored by TLC, and the reaction of 1A was almost complete after 3 hours. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate. After extraction, 1 mol / L hydrochloric acid was added to the organic layer to adjust the pH to 5-6, and then extracted again. The organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL), and finally dried with anhydrous sodium sulfate, filtered, and dried to obtain a crude product of 1.3 g yellow oil. The crude product was purified by chromatography (DCM: MeOH = 15: 1) to obtain 1C as a light yellow oil of 0.86 g, with a yield of 69.6%. (+)-ESI-MS: m / z 539.3492 (calcd. 539.3479 for C 32 H 47 N 2 O 5 + [M-Br] + ).

[0069] Step 4: Synthesis of 5-(2-(((S)-3-(aminomethyl)-5-methylhexanoyl)oxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide hydrochloride (Compound 1)

[0070] In a 100 mL round-bottom flask, 0.86 g of the product 1C in step 3 was added, dissolved in ethyl acetate (with a small amount of methanol added dropwise), and a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise while stirring. The mixture was stirred at room temperature and the reaction process was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 1C was basically reacted. The filter cake was filtered and dried under reduced pressure to obtain 0.6 g of a white solid (compound 1) with a yield of 77.9%. 1 H NMR (500 MHz, DMSO-d 6 )δ8.34(s,3H),7.59 / 7.53(d,J=7.5Hz,1H),7.44(q,J=7.3Hz,1H),7.38(t,J=7.2Hz,1H),7.34-7.28(m,2H),7.25(t,J=8.3Hz,3 H),7.22 / 7.16(d,J=7.7Hz,1H),5.99 / 5.96(s,1H),4.78-4.66(m,1H),4.53(q,J=12.4Hz,1H),4.22(d,J=7.4Hz,1H),3.83(p,J=5 .6Hz,1H),3.36(s,2H),3.29-3.18(m,1H),3.17 / 2.98(s,3H),2.77(d,J=5.9Hz,2H),2.71-2.62(m,1H),2.45-2.36(m,1H),2.31 -2.23(m,2H),1.90(s,1H),1.61(h,J=6.6Hz,1H),1.33-1.17(m,2H),1.11(dq,J=14.7,7.3Hz,1H),0.88(dd,J=11.0,6.4Hz,6H). 13 C NMR (126 MHz, DMSO-d 6)δ172.19 / 172.15,145.11 / 144.98,143.10 / 142.89,135.69 / 135.57,130.87 / 130 .79,129.49 / 129.39,128.99,128.38 / 128.21,128.12,127.97,124.98 / 124.89,85 .37 / 85.01,65.89,65.11 / 65.01,61.58 / 61.49,59.77,56.79 / 56.22,49.12,42.36 / 41.35,36.72 / 36.62,31.45,25.14,22.99 / 22.94,22.29 / 22.04.(+)-ESI-MS:m / z 439.2977(calcd.439.2955forC 27 H 39 N 2 O 3 + [M-Br] + ).

[0071] Example 2: Synthesis of 5-(2-(2-(1-(aminomethyl)cyclohexyl)acetoxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazin-5-ium bromide hydrochloride (Compound 2)

[0072] The synthetic route is as follows:

[0073]

[0074] Step 1: Synthesis of 2-(1-((tert-butyloxycarbonyl)amino)methyl)cyclohexyl)acetic acid (2B)

[0075] In a 100 mL round-bottom flask, gabapentin (1.7 g, 10 mmol, 1.0 eq) and 1 mol / L sodium hydroxide aqueous solution (0.8 g, 20 mmol, 2.0 eq) were added, and a mixed solution of di-tert-butyl dicarbonate (2.65 g, 12 mmol, 1.2 eq) and 25 mL of dioxane was added dropwise under stirring. After stirring at room temperature for 2 hours, TLC monitored that pregabalin had reacted completely. The reaction solution was cooled to room temperature, and dichloromethane (3 × 15 mL) was added for extraction. The aqueous phases were combined and NaHCO was added. 3 The pH was adjusted to 4-5, and dichloromethane (3×20 mL) was added for re-extraction. The organic layers were combined, washed with 15 mL of saturated brine, dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain 2B as a white solid powder (2.25 g), with a yield of 83.3%. (+)-ESI-MS: m / z 272.1866 (calcd. 272.1856 for C14 H 26 NO 4 + [M+H] + ).

[0076] Step 2: Synthesis of 5-(2-(2-(1-(((tert-butyloxycarbonyl)amino)methyl)cyclohexyl)acetoxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide (2C)

[0077] In a 100 mL round-bottom flask, 20 mL of dichloromethane, 1A (0.76 g, 2 mmol, 1.0 eq), 2B (0.65 g, 2.4 mmol, 1.2 eq), DMAP (0.024 g, 0.2 mmol, 0.1 eq) were added, and EDCI (0.46 g, 2.4 mmol, 1.2 eq) was added after stirring, and the reaction was carried out at room temperature. The reaction process was monitored by TLC, and the reaction of 1A was almost complete after 3 hours. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate. After extraction, 1 mol / L hydrochloric acid was added to the organic layer to adjust the pH to 5-6, and then extracted again. The organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL), and finally dried with anhydrous sodium sulfate, filtered, and dried by rotation to obtain a crude product of 1.5 g yellow oil. The crude product was purified by chromatographic column (DCM: MeOH = 15: 1) to obtain 2C as a light yellow oil of 0.95 g, with a yield of 75.4%. (+)-ESI-MS: m / z 551.3491 (calcd. 551.3479 for C 33 H 47 N 2 O 5 + [M-Br] + ).

[0078] Step 3: Synthesis of 5-(2-(2-(1-(aminomethyl)cyclohexyl)acetoxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide hydrochloride (Compound 2)

[0079] In a 100 mL round-bottom flask, 0.95 g of the product 2C in step 3 was added, dissolved in ethyl acetate (with a small amount of methanol added dropwise), and a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise while stirring. The mixture was stirred at room temperature and the reaction process was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 2C was basically reacted. The filter cake was filtered and dried under reduced pressure to obtain 0.7 g of a white solid (compound 2) with a yield of 82.3%. 1 H NMR (500 MHz, DMSO-d6 )δ8.37(s,3H),7.53 / 7.49(d,J=7.3Hz,1H),7.35(t,J=7.8Hz,1H),7.30(t,J=7.3Hz,1H),7.24(d,J=7.2Hz,2H ),7.21-7.14(m,3H),7.13 / 7.07(d,J=7.6Hz,1H),5.92 / 5.89(s,1H),4.68 / 4.64(d,J=12.4Hz,1H),4.45(t,J=1 1.2Hz,1H),4.12(p,J=5.9Hz,1H),3.79(t,J=8.5Hz,1H),3.31(s,2H),3.21-3.09(m,2H),2.93(s,1H),2.85-2 .76(m,2H),2.59(s,1H),2.44(s,3H),2.20(dq,J=14.3,7.4Hz,2H),1.82(s,1H),1.33(dd,J=16.5,6.6Hz,9H). 13 C NMR (126 MHz, DMSO-d 6 )δ171.29 / 171.28,145.14 / 145.04,143.13 / 142.94,135.71 / 135.61,130.89 / 130 .78,129.51 / 129.44,129.02,128.38 / 128.19,128.11,127.99,124.98 / 124.87,85 .39 / 85.09,66.03 / 65.82,65.12 / 65.02,61.62 / 61.51,60.92 / 59.91,49.11,47.42 / 45.39,35.43 / 35.38,33.09 / 33.02,25.68,22.26 / 21.97,21.12.(+)-ESI-MS:m / z 451.2987(calcd.451.2955for C 28 H 39 N 2 O 3 + [M-Br] + ).

[0080] Example 3: Synthesis of 5-(3-(((R)-3-(aminomethyl)-5-methylhexanoyl)oxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazine-5-bromide hydrochloride (Compound 3)

[0081] The synthetic route is as follows:

[0082]

[0083] Step 1: Synthesis of 5-(3-hydroxypropyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazin-5-ium bromide (2A)

[0084] In a 100 mL round-bottom flask, 10 mL of acetonitrile and nefopam (5.0 g, 20 mmol, 1.0 eq) were added, and 3-bromo-1-propanol (5.56 g, 40 mmol, 2.0 eq) was added under stirring. The mixture was stirred at 70°C and monitored by TLC. After 2 hours, the nefopam reaction was complete. The reaction solution was cooled to room temperature, and the excess solvent was removed by rotary evaporator. 60 mL of ethyl acetate was added and stirred for 1 hour, and then filtered and dried to obtain 2A as a light red solid of 6.7 g, with a yield of 85.9%. (+)-ESI-MS m / z 312.1966 (calcd.312.1958 for C 20 H 26 NO 2 + [M-Br] + ).

[0085] Step 2: Synthesis of 5-(3-(((R)-3-(((tert-butyloxycarbonyl)amino)methyl)-5-methylhexanoyl)oxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide hydrochloride (3C)

[0086] In a 100 mL round-bottom flask, 20 mL of dichloromethane, 2A (0.78 g, 2 mmol, 1.0 eq), 2B (0.62 g, 2.4 mmol, 1.2 eq), and DMAP (0.024 g, 0.2 mmol, 0.1 eq) were added, and EDCI (0.46 g, 2.4 mmol, 1.2 eq) was added after stirring, and the reaction was carried out at room temperature. The reaction process was monitored by TLC, and the reaction of 2A was almost complete after 3 hours. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate, extracted, and the organic layer was adjusted to pH 5-6 by adding 1 mol / L hydrochloric acid, extracted again, and the organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL), and finally dried with anhydrous sodium sulfate, filtered, and spin-dried to obtain a crude product of 1.35 g of yellow oil. The crude product was purified by chromatographic column (DCM: MeOH = 15: 1) to obtain 3C as a light yellow oil of 0.91 g, with a yield of 72.2%. (+)-ESI-MS: m / z 553.3649 (calcd. 553.3636 for C 33 H 49 N 2 O 5+ [M-Br] + ).

[0087] Step 3: Synthesis of 5-(3-(((R)-3-(aminomethyl)-5-methylhexanoyl)oxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide hydrochloride (Compound 3)

[0088] In a 100 mL round-bottom flask, 0.91 g of the product 3C in step 3 was added, dissolved in ethyl acetate (with a small amount of methanol added dropwise), and a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise while stirring. The mixture was stirred at room temperature and the reaction process was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 3C was basically reacted. The filter cake was filtered and dried under reduced pressure to obtain 0.62 g of a white solid (compound 3) with a yield of 75.6%. 1 H NMR (500 MHz, DMSO-d 6 )δ8.34(s,3H),7.55 / 7.51(d,J=7.5Hz,1H),7.43(q,J=7.3Hz,1H),7.37(t,J=7.2Hz,1H),7.33-7.28(m,2H),7.25(t,J=8.3Hz,3H),7.20 / 7.15(d,J=7.7Hz,1H),5.97 / 5.95(s,1H),4.73-4.62(m,1H),4.50(q,J=12.4Hz,1H),4.20(d,J=7.4Hz,1H),4.15-4.08(m,1H),4.07-3.99( m,1H),3.80(p,J=5.6Hz,1H),3.35(s,2H),3.26-3.17(m,1H),3.15 / 2.96(s,3H),2.76(d,J=5.9Hz,2H),2.69-2.60(m,1H),2.43-2.32(m, 1H),2.28-2.19(m,2H),1.90(s,1H),1.58(h,J=6.6Hz,1H),1.31-1.16(m,2H),1.08(dq,J=14.7,7.3Hz,1H),0.85(dd,J=11.0,6.4Hz,6H). 13 C NMR (126 MHz, DMSO-d 6)δ172.16 / 172.13,145.10 / 144.97,143.08 / 142.87,135.65 / 135.50,130.80 / 130.75 ,129.46 / 129.36,128.96,128.30 / 128.16,128.09,127.90,124.92 / 124.83,85.32 / 8 4.98,65.81,65.05 / 64.95,61.54 / 61.42,59.72,56.73 / 56.15,49.02,48.8 / 47.3,42 .26 / 40.95,36.58 / 36.52,31.35,25.04,22.96 / 22.94,22.27 / 22.00.(+)-ESI-MS:m / z 453.3166(calcd.453.3112for C 28 H 41 N 2 O 3 + [M-Br] + ).

[0089] Example 4: Synthesis of 5-(3-(2-(1-(aminomethyl)cyclohexyl)acetoxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazine-5-bromide hydrochloride (Compound 4)

[0090] The synthetic route is as follows:

[0091]

[0092] Step 1: Synthesis of 5-(3-(2-(1-(((tert-butyloxycarbonyl)amino)methyl)cyclohexyl)acetoxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazin-5-ium bromide (4C)

[0093] In a 100 mL round-bottom flask, 20 mL of dichloromethane, 2A (0.78 g, 2 mmol, 1.0 eq), 1B (0.65 g, 2.4 mmol, 1.2 eq), and DMAP (0.024 g, 0.2 mmol, 0.1 eq) were added, and EDCI (0.46 g, 2.4 mmol, 1.2 eq) was added after stirring, and the reaction was carried out at room temperature. The reaction process was monitored by TLC, and the reaction of 2A was almost complete after 3 hours. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate, extracted, and the organic layer was added with 1 mol / L hydrochloric acid to adjust the pH to 5-6, extracted again, and the organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL), and finally dried with anhydrous sodium sulfate, filtered, and spin-dried to obtain a crude product of 1.45 g of yellow oil. The crude product was purified by chromatographic column (DCM: MeOH = 15: 1) to obtain 4C as a light yellow oil of 0.99 g, with a yield of 77.3%. (+)-ESI-MS: m / z 565.3652 (calcd. 565.3636 for C 34 H 49 N 2 O 5 + [M-Br] + ).

[0094] Step 2: Synthesis of 5-(3-(2-(1-(aminomethyl)cyclohexyl)acetoxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazin-5-ium bromide hydrochloride (Compound 4)

[0095] In a 100 mL round-bottom flask, 0.99 g of the product 4C in step 3 was added, dissolved in ethyl acetate (with a small amount of methanol added dropwise), and a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise while stirring. The mixture was stirred at room temperature and the reaction process was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 4C was basically reacted. The filter cake was filtered and dried under reduced pressure to obtain 0.73 g of a white solid (compound 4) with a yield of 84.2%. 1 H NMR (500 MHz, DMSO-d 6)δ8.34(s,3H),7.49 / 7.46(d,J=7.3Hz,1H),7.33(t,J=7.8Hz,1H),7.29(t,J=7.3Hz,1H),7.22(d,J=7.2Hz,2H),7.20-7.14(m,3H),7.12 / 7.06(d,J=7.6Hz,1H),5.89 / 5.88(s,1H),4.66 / 4.62(d,J=12.4Hz,1H),4.44(t,J=11.2Hz,1H),4.10(p,J=5.9Hz,1H),4.05-3.92(m,2H),3.77(t,J=8.5Hz,1H),3.30(s,2H),3.18-3.03(m,2H),2.90(s,1H),2.83-2.75(m,2H),2.56(s,1H),2.42(s,3H),2.20(dq,J=14.3,7.4Hz,2H),1.82(s,1H),1.30(dd,J=16.5,6.6Hz,9H). 13 CNMR(126MHz,DMSO-d 6 )δ171.24 / 171.23,145.09 / 144.98,143.08 / 142.86,135.64 / 135.53,130.81 / 130.74,129.45 / 129.37,128.96,128.31 / 128.16,128.09,127.91,124.92 / 124.84,85.35 / 85.00,65.98 / 65.79,65.07 / 64.99,61.56 / 61.45,60.89 / 59.85,56.85 / 56.13,49.03,47.39 / 45.38,35.39 / 35.35,33.04 / 33.00,25.62,22.22 / 21.93,21.09.(+)-ESI-MS:m / z 465.3146(calcd.465.3112for C 29 H 41 N 2 O 3 + [M-Br] + )。

[0096] Example 5: Synthesis of 5-(2-((4-aminobutanoyl)oxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazin-5-ium bromide hydrochloride (Compound 5)

[0097] The synthetic route is as follows:

[0098]

[0099] Step 1: Synthesis of 4-(tert-butyloxycarbonyl)amino)butyric acid (3B)

[0100] In a 100 mL round-bottom flask, γ-aminobutyric acid (1.03 g, 10 mmol, 1.0 eq) and 1 mol / L sodium hydroxide aqueous solution (0.8 g, 20 mmol, 2.0 eq) were added, and a mixed solution of di-tert-butyl dicarbonate (2.65 g, 12 mmol, 1.2 eq) and 25 mL of dioxane was added dropwise under stirring. After stirring at room temperature for 2 hours, TLC monitored that the γ-aminobutyric acid had reacted completely. The reaction solution was cooled to room temperature, and dichloromethane (3 × 15 mL) was added for extraction. The aqueous phases were combined and NaHCO was added. 3 The pH was adjusted to 4-5, and dichloromethane (3×20 mL) was added for re-extraction. The organic layers were combined, washed with 15 mL of saturated brine, dried over anhydrous sodium sulfate, filtered, and spin-dried to obtain 3B as a white solid powder (1.6 g) with a yield of 80.1%. 1 H NMR(500MHz,Chloroform-d)δ4.78(s,1H),3.79-3.67(m,2H),2.43-2.36(m,2H),1.83(p,J=7.0H z,2H),1.45(s,9H),1.25(td,J=7.0,0.9Hz,1H).(+)-ESI-MS:m / z204.1252(calcd.204.1230for C 9 H 18 NO 4 + [M+H] + ).

[0101] Step 2: Synthesis of 5-(2-((4-((tert-butyloxycarbonyl)amino)butanoyl)oxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide (5C)

[0102] In a 100 mL round-bottom flask, 20 mL of dichloromethane, 1A (0.76 g, 2 mmol, 1.0 eq), 3B (0.48 g, 2.4 mmol, 1.2 eq), DMAP (0.024 g, 0.2 mmol, 0.1 eq) were added, and EDCI (0.46 g, 2.4 mmol, 1.2 eq) was added after stirring, and the reaction was carried out at room temperature. The reaction process was monitored by TLC, and the reaction of 1A was almost complete after 3 hours. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate. After extraction, 1 mol / L hydrochloric acid was added to the organic layer to adjust the pH to 5-6, and then extracted again. The organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL), and finally dried with anhydrous sodium sulfate, filtered, and spin-dried to obtain a crude product of 1.1 g of yellow oil. The crude product was purified by chromatographic column (DCM: MeOH = 15: 1) to obtain 5C as a light yellow oil of 0.74 g, with a yield of 66.1%. (+)-ESI-MS: m / z 483.2867 (calcd. 483.2853 for C 28 H 39 N 2 O 5 + [M-Br] + ).

[0103] Step 3: Synthesis of 5-(2-((4-aminobutyryl)oxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide hydrochloride (Compound 5)

[0104] In a 100 mL round-bottom flask, 0.74 g of the product 5C in step 3 was added and dissolved in ethyl acetate (with a small amount of methanol added dropwise). A saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise while stirring. The mixture was stirred at room temperature and the reaction process was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 5C was basically reacted. The filter cake was filtered and dried under reduced pressure to obtain 0.55 g of a white solid (compound 5) with a yield of 84.6%. 1 H NMR (500 MHz, DMSO-d 6)δ6.89 / 6.85(d,J=7.3Hz,1H),6.81-6.76(m,1H),6.75(t,J=7.6Hz,1H),6.68(t,J=7.1Hz,2H),6.63(d ,J=7.2Hz,2H),6.61(d,J=7.4Hz,1H),6.57 / 6.52(d,J=7.6Hz,1H),5.34 / 5.32(s,1H),3.63-3.52(m,2H ),3.51-3.44(m,1H),3.43-3.37(m,1H),3.19-3.04(m,3H),2.68(s,2H),2.33(s,2H),2.20-2.13(m,2H ),1.85(d,J=17.0Hz,4H),1.65 / 1.39(td,J=12.9,12.3,5.7Hz,2H),1.29-1.16(m,2H).(+)-ESI-MS:m / z 383.2351(calcd.383.2329for C 23 H 31 N 2 O 3 + [M-Br] + ).

[0105] Example 6: Synthesis of 5-(3-((4-aminobutyryl)oxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide hydrochloride (Compound 6)

[0106] The synthetic route is as follows:

[0107]

[0108] Step 1: Synthesis of 5-(3-((4-((tert-butyloxycarbonyl)amino)butanoyl)oxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide (6C)

[0109] In a 100 mL round-bottom flask, 20 mL of dichloromethane, 2A (0.78 g, 2 mmol, 1.0 eq), 3B (0.48 g, 2.4 mmol, 1.2 eq), and DMAP (0.024 g, 0.2 mmol, 0.1 eq) were added, and EDCI (0.46 g, 2.4 mmol, 1.2 eq) was added after stirring, and the mixture was reacted at room temperature. The reaction process was monitored by TLC, and the reaction of 2A was almost complete after 3 hours. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate, extracted, and the organic layer was added with 1 mol / L hydrochloric acid to adjust the pH to 5-6, extracted again, and the organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL), and finally dried with anhydrous sodium sulfate, filtered, and spin-dried to obtain a crude product of 1.09 g of yellow oil. The crude product was purified by chromatographic column (DCM: MeOH = 15: 1) to obtain 3C as a light yellow oil of 0.81 g, with a yield of 70.4%. (+)-ESI-MS: m / z 497.3035 (calcd. 497.3010 for C 29 H 41 N 2 O 5 + [M-Br] + ).

[0110] Step 2: Synthesis of 5-(3-((4-aminobutyryl)oxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazinium-5-bromide hydrochloride (Compound 6)

[0111] In a 100 mL round-bottom flask, 0.81 g of the product 6C in step 3 was added, dissolved in ethyl acetate (with a small amount of methanol added dropwise), and a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise while stirring. The mixture was stirred at room temperature and the reaction process was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 6C was basically reacted. The filter cake was filtered and dried under reduced pressure to obtain 0.68 g of a white solid (compound 6) with a yield of 94.4%. 1 H NMR (500 MHz, DMSO-d 6)δ6.87 / 6.83(d,J=7.3Hz,1H),6.79-6.75(m,1H),6.72(t,J=7.6Hz,1H),6.65(t,J=7.1Hz,2H),6.61(d,J=7.2 Hz,2H),6.59(d,J=7.4Hz,1H),6.55 / 6.50(d,J=7.6Hz,1H),5.31 / 5.29(s,1H),3.97 / 3.83(t,J=13.4Hz,2H),3. 59-3.49(m,2H),3.48-3.43(m,1H),3.42-3.35(m,1H),3.17-3.02(m,3H),2.68(s,2H),2.28(s,2H),2.17-2.1 0(m,2H),1.83(d,J=17.0Hz,4H),1.61 / 1.36(td,J=12.9,12.3,5.7Hz,2H),1.26-1.14(m,2H).(+)-ESI-MS:m / z 397.2497(calcd.397.2486for C 24 H 33 N 2 O 3 + [M-Br] + ).

[0112] Example 7: Evaluation of the analgesic effect of nefopam in the carrageenan-induced inflammatory pain model

[0113] The carrageenan-induced inflammatory pain experiment is an animal model widely used to evaluate acute inflammatory pain. λ-Carrageenan is a sulfated polysaccharide extracted from red seaweed. Its use in animals can cause local inflammatory responses, such as tissue swelling, congestion and hyperalgesia. The inflammatory pain induced by intraplantar injection of 20 μL of 1% carrageenan solution in mice reached a peak at 3 hours and subsided within 24 to 72 hours. After modeling, the mechanical withdrawal threshold of mice was significantly lower than the baseline level, indicating that inflammatory pain was successfully induced. As shown in the figure, nefopam (1, 3, 5, 10 mg / kg) dose-dependently reduced the inflammatory pain induced by carrageenan [F(35, 210) = 21.56, p < 0.0001, Figure 5 A; F(4,25)=31.11, p<0.0001, Figure 5 B]. The analgesic inhibition rates of 1, 3, 5, and 10 mg / kg nefopam in inflammatory pain were 36.27%, 59.18%, 77.00%, and 93.15%, respectively. The median effective dose ED 50 1.80±0.59mg / kg( Figure 5 ).

[0114] Example 8: Evaluation of the analgesic effect of nefopam in the iodoacetic acid-induced osteoarthritis pain model

[0115] Osteoarthritis is a chronic degenerative joint disease characterized by progressive joint pain. There is an urgent need to explore new and effective treatments for osteoarthritis pain. Iodoacetic acid induces osteoarthritis in mice by digesting cartilage, proliferating inflammatory cells, and destroying cartilage. 24 hours after the knee joint of mice was injected with 20 μL of 1% iodoacetic acid, the mechanical paw withdrawal threshold was significantly reduced, indicating that the osteoarthritis pain model was successfully established. Nefopam (3, 10, 30, 60 mg / kg) showed significant dose-dependent analgesic effects in the osteoarthritis pain model [F(35, 210)=51.16, p<0.0001, Figure 6 A], the results showed that AUC [F(4,25)=82.32, p<0.0001, Figure 6 B]. In the osteoarthritis pain induced by iodoacetic acid, the analgesic inhibition rates of nefopam at four doses from low to high, 3, 10, 30, and 60 mg / kg, were 16.00%, 30.02%, 45.99%, and 57.27%, respectively. The median effective dose ED 50 38.11±2.08mg / kg( Figure 6 ).

[0116] Example 9: Evaluation of the analgesic effect of nefopam in a paclitaxel-induced neuropathic pain model

[0117] Paclitaxel can induce a peripheral neuropathic pain state characterized by allodynia and hyperalgesia caused by noxious or innocuous stimuli. On the 6th day, the mechanical withdrawal threshold of mice in the model group was significantly reduced compared with the baseline value, indicating that paclitaxel-induced neuropathic pain in mice was successfully established. Nefopam (1, 3, 5, 10 mg / kg) reversed paclitaxel-induced mechanical allodynia in a dose-dependent manner, and the analgesic effect reached a peak at 90 minutes after administration [F(35, 210) = 22.60, p < 0.0001, Figure 7 A; F(4,25)=28.55, p<0.0001, Figure 7 B] The ED value of Nefopam was obtained by dose-response curve. 50 The value was 2.40±0.57mg / kg, and the analgesic inhibition rates were 35.92%, 49.89%, 63.11%, and 81.02% ( Figure 7 ).

[0118] Example 10: Evaluation of the analgesic effect of pregabalin / gabapentin in the carrageenan-induced inflammatory pain model

[0119] λ-Carrageenan is a chemical substance that stimulates inflammation by releasing proinflammatory factors (including prostaglandins, leukotrienes, histamine, serotonin, bradykinin and TNF-α, etc.). Intraplantar injection of 20 μL of 1% carrageenan solution into mice induced local inflammatory responses (peaked in 3 hours and subsided within 24 to 72 hours), such as tissue swelling, congestion and hyperalgesia. Three hours after intraplantar injection of carrageenan into mice, the mechanical withdrawal threshold was significantly lower than the baseline level, indicating that inflammatory pain was successfully induced. As shown in the figure, both pregabalin (3, 6, 12, 24 mg / kg) and gabapentin (25, 50, 75, 100 mg / kg) reduced the inflammatory pain caused by carrageenan in a dose-dependent manner [F(35, 210) = 59.22, p < 0.0001, Figure 8 A; F(4,25)=158.70, p<0.0001, Figure 8 B; F(35,210)=27.88, p<0.0001, Figure 8 C; F(4,25)=57.77, p<0.0001, Figure 8 D]. The analgesic inhibition rates of 3, 6, 12, and 24 mg / kg pregabalin in inflammatory pain were 29.26%, 46.86%, 64.06%, and 80.48%, respectively. The median effective dose ED 50 The analgesic inhibition rates of 25, 50, 75, and 100 mg / kg gabapentin in inflammatory pain were 16.15%, 47.20%, 67.86%, and 80.76%, respectively. The median effective dose ED 50 52.80±1.10mg / kg( Figure 8 ).

[0120] Example 11: Evaluation of the analgesic effect of pregabalin / gabapentin in the iodoacetic acid-induced osteoarthritis pain model

[0121] Pain caused by joint damage is the main clinical feature of osteoarthritis, which is mainly caused by synovial neuropathic inflammation and subchondral nerve damage. With the occurrence of joint damage, pain occurs and gradually causes osteoarthritis patients to lose joint mobility. The iodoacetic acid-induced osteoarthritis model has become one of the most popular models for studying the pain process and intervention effects of osteoarthritis. It can not only evaluate the analgesic effect of drugs, but also the anti-inflammatory effect of drugs. 24 hours after the knee joint of mice was injected with 20μL 1% iodoacetic acid, the mechanical paw withdrawal threshold was significantly reduced, indicating that the osteoarthritis pain model was successfully established. Pregabalin (6, 12, 24, 48mg / kg) and gabapentin (25, 50, 75, 100mg / kg) showed significant dose-dependent analgesic effects in the osteoarthritis pain model [F(35, 210) = 65.30, p < 0.0001, Fig. 9 A; F(35,210)=82.29, p<0.0001, Fig. 9 C], the results showed that AUC [F(4,25)=80.38, p<0.0001, Fig. 9 B; F(4,25)=239.90, p<0.0001, Fig. 9 D]. In iodoacetic acid-induced osteoarthritis pain: the analgesic inhibition rates of pregabalin at four doses from low to high, 6, 12, 24, and 48 mg / kg, were 23.07%, 32.34%, 44.38%, and 60.36%, respectively. The median effective dose ED 50 The analgesic inhibition rates of gabapentin at four doses from low to high, 25, 50, 75, and 100 mg / kg, were 23.00%, 45.77%, 61.14%, and 70.00%, respectively. The median effective dose ED 50 56.00±30.20mg / kg( Fig. 9 ).

[0122] Example 12: Evaluation of the analgesic effect of pregabalin / gabapentin in a paclitaxel-induced neuropathic pain model

[0123] Some evidence suggests that in animal models of neuropathic pain induced by chemotherapeutic drugs (such as paclitaxel, vincristine and cisplatin), excessive excitability of dorsal root ganglia and spinal dorsal horn neurons may lead to the development of thermal hyperalgesia and mechanical hyperalgesia. On day 6, the mechanical withdrawal threshold of mice in the model group was significantly reduced compared with the baseline value, indicating that paclitaxel-induced neuropathic pain in mice was successfully established. Pregabalin (3, 6, 12, 24 mg / kg) dose-dependently reversed paclitaxel-induced mechanical allodynia, and the analgesic efficacy reached a peak at 90 minutes after administration [F(35, 210) = 28.31, p < 0.0001, Fig.10 A; F(4,25)=114.00, p<0.0001, Fig.10 B]. Gabapentin (25, 50, 75, 100 mg / kg) also reversed mechanical allodynia in a dose-dependent manner, and the analgesic effect reached a peak at 120 minutes after administration [F(35, 210) = 29.15, p < 0.0001, Fig.10 C; F(4,25)=70.95, p<0.0001, Fig.10 D] The median effective dose (ED) of pregabalin and gabapentin was obtained by dose-response curve. 50The values ​​were 7.50±2.23mg / kg and 45.60±0.20mg / kg, respectively. The analgesic inhibition rates of the four doses were 22.30%, 42.44%, 65.78%, 82.45% and 27.32%, 53.60%, 69.30%, 78.47% ( Fig.10 ).

[0124] Example 13: Evaluation of the analgesic effects of Compound 3 and Compound 4 in the carrageenan-induced inflammatory pain model

[0125] Three hours after carrageenan was injected into the soles of the mice, the mechanical withdrawal threshold was significantly lower than the baseline level, indicating that inflammatory pain was successfully induced. After the administration of compound 3 and compound 4, the mechanical withdrawal threshold of the mice was significantly increased [F(24,150)=86.65, p<0.0001, Fig.11 A; F(3,20)=100.20, p<0.0001, Fig.11 C]. Both conjugated drugs produced dose-dependent analgesic effects on mice [F(24,150)=84.46,p<0.0001, Fig.11 B; F(3,20)=188.20, p<0.0001, Fig.11 D]. The analgesic inhibition rates of compound 3 and compound 4 were 79.16%, 70.46%, 57.31% and 93.51%, 69.84%, 43.09%, respectively. The median effective dose ED 50 The median effective dose ED of compound 3 and compound 4 in the inflammatory pain model was 0.52±0.29 mg / kg and 5.95±0.83 mg / kg. 50 Lower ED than nefopam and pregabalin / gabapentin combination 50 (The synergistic anti-nociceptive effects of nefopam and gabapentinoids in inflammatory, osteoarthritis, and neuropathic pain mouse models. European Journal of Pharmacology 977 (2024) 176738. Nefopam + pregabalin: 1.31 mg / kg; Nefopam + gabapentin: 9.77 mg / kg).

[0126] Example 14: Evaluation of the analgesic effects of Compound 3 and Compound 4 in the iodoacetic acid-induced osteoarthritis pain model

[0127] After administration of compound 3 and compound 4, the mechanical withdrawal threshold of mice was significantly increased [F(24,150)=84.40, p<0.0001, Fig.12 A; F(24,150)=38.38, p<0.0001, Fig.12 C]. Both conjugated drugs produced significant, dose-dependent analgesic effects on mice [F(3,20)=85.38, p<0.0001, Fig.12 B; F(3,20)=122.00, p<0.0001, Fig.12 D]. The analgesic inhibition rates of compound 3 at doses of 1, 5, and 10 mg / kg were 32.50%, 52.82%, and 68.96%, respectively, and the analgesic inhibition rates of compound 4 at doses of 1, 5, and 10 mg / kg were 16.42%, 49.07%, and 67.57%, respectively. The median effective dose ED of compound 3 and compound 4 was 50 They were 3.41±1.16 and 5.03±0.26 mg / kg respectively.

[0128] The conjugated drug compounds 3 and 4 both showed improved analgesic activity in the mouse osteoarthritis pain model. Compared with the combination, the half effective dose ED of the conjugated drug was 50 Significantly reduced (The synergistic anti-nociceptive effects of nefopam and gabapentinoids in inflammatory, osteoarthritis, and neuropathic pain mouse models. European Journal of Pharmacology 977 (2024) 176738. Compound 3 (10.80 ± 1.19 mg / kg) reduced by 3.17 times; Compound 4 (24.92 ± 6.93 mg / kg) reduced by 4.95 times. The half effective dose ED of nefopam alone in this model 50 It is 38.11 mg / kg. The synthesis of the conjugated drug makes up for the insufficient efficacy of nefopam alone in the treatment of osteoarthritis pain.

[0129] Example 15: Evaluation of the analgesic effects of Compound 3 and Compound 4 in the paclitaxel-induced neuropathic pain model

[0130] After paclitaxel-induced neuropathic pain in mice was successfully established, the mechanical withdrawal threshold of mice in the model group was significantly reduced. Compound 3 and compound 4 were administered at a dose of 1, 5, and 10 mg / kg, respectively, which significantly improved paclitaxel-induced neuropathic pain, and the analgesic efficacy was dose-dependent [F(24,150)=84.40, p<0.0001, Fig.13 A; F(3,20)=60.51, p<0.0001, Fig.13 B; F(24,150)=36.79, p<0.0001, Fig.13 C; F(3,20)=80.61, p<0.0001, Fig.13 D]. The analgesic inhibition rates of compound 3 at doses of 1, 5, and 10 mg / kg were 46.44%, 64.07%, and 71.34%, respectively. The median effective dose ED 50 The analgesic inhibition rates of compound 4 at doses of 1, 5, and 10 mg / kg were 25.41%, 48.80%, and 70.49%, respectively, and the median effective dose ED 50 The conjugated drug compounds 3 and 4 have improved analgesic efficacy in the neuropathic pain model, with the median effective dose ED 50 Much lower than the ED of combined medication 50 (The synergistic anti-nociceptive effects of nefopam and gabapentinoids in inflammatory, osteoarthritis, and neuropathic pain mouse models. European Journal of Pharmacology 977 (2024) 176738. Nefopam + pregabalin: 4.95 mg / kg; Nefopam + gabapentin: 24.00 mg / kg).

[0131] Example 16: Motor coordination of compound 3 and compound 4 in the rotarod test

[0132] The fatigue rotarod test is a classic method for evaluating the effects of drugs on animal behavior. 50 The present invention uses this experiment to evaluate the effect of naphthalene compound 3 (3.41 mg / kg, the highest ED value among the three models) on the motor coordination ability of mice. 50 dose) and compound 4 (5.95 mg / kg, the highest ED 50 The results showed that the half effective dose of ED 50 There was no significant difference in the falling latency of mice after administration of the drug compared with the control group ( Fig.14 ), indicating that the conjugate drug compounds 3 and 4 do not cause ataxia or sedation.

[0133] Example 17: Safety of Compound 3 and Compound 4 in Acute Toxicity Experiments

[0134] Acute toxicity tests are used to determine the acute LD50 in the short term after administration. 50 After intragastric administration of the coupled drug compound 3 (2000 mg / kg), compound 4 (2000 mg / kg) or saline, the mice were observed for 7 days. After 7 days, no mice in the drug group or the blank group died, and no obvious adverse reactions were observed.

[0135] In summary, the conjugated drugs of nefopam and γ-aminobutyric acid analogs have the characteristics of high efficiency and low toxicity, which provides a new idea for clinical analgesia. Compared with traditional compound preparations and combination medications, conjugated drugs can effectively reduce drug interactions, without considering the dosage ratio, and are more convenient to take, increase patient compliance with medication, and improve the quality of life of patients.

Claims

1. A compound having a synergistic analgesic effect, characterized in that: The chemical structure of the compound is as follows: in, A structural fragment selected from the chemical structure of gabapentin, pregabalin, γ-aminobutyric acid, melogabalin, and cligabalin except for the hydrogen on the carboxyl group; X is selected from halogen or an acid radical of any of the following acids: carbonic acid, sulfuric acid, phosphoric acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, citric acid, malic acid, tartaric acid, lactic acid, pyruvic acid, acetic acid, maleic acid, succinic acid, fumaric acid, salicylic acid, phenylacetic acid, mandelic acid, ferulic acid; m is selected from 0, 1, and 2.

2. The compound according to claim 1, characterized in that In the chemical structure, Selected from X is selected from F, Cl, Br, I; m is selected from 0 and 1.

3. The compound according to claim 1, characterized in that It is selected from any one of the following compounds:

4. A pharmaceutical composition, characterized in that Contains the compound according to any one of claims 1 to 3 and a pharmaceutically acceptable carrier.

5. A method for preparing the compound according to any one of claims 1 to 3, characterized in that: R1 is selected from Boc, Cbz, Fomc, Alloc protecting groups, m, As defined in claim 1, the preparation method comprises the following steps: (1) protecting the amino group in the structure of gabapentin, pregabalin, γ-aminobutyric acid, melogabalin or cligabalin to obtain intermediate I; (2) Using an alkaline reagent to dissociate Nefopam hydrochloride into Nefopam, and reacting the free Nefopam with the intermediate The intermediate II is obtained by heating the reaction in a reaction solvent; (3) subjecting the intermediate I obtained in step (1) to a condensation reaction with the intermediate II obtained in step (2) in the presence of a catalyst to obtain an intermediate III; (4) Removing the protecting group from the intermediate III obtained in step (3) under acidic, alkaline or neutral conditions to obtain the compound.

6. The preparation method according to claim 5, characterized in that: The molar ratio of gabapentin, pregabalin, γ-aminobutyric acid, melogabalin or cligabalin to the amino protecting agent in step (1) is 1:(1-10); The alkaline reagent described in step (2) is selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, sodium bicarbonate, potassium bicarbonate, the reaction solvent is selected from acetonitrile, acetone, tetrahydrofuran, N,N-diformylformamide or N,N-diformylacetamide, nefopam and intermediate The molar ratio is 1:(2~10).

7. The preparation method according to claim 5, characterized in that: The catalyst described in step (3) is selected from 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 4-dimethylaminopyridine, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, benzotriazole-N,N,N',N'-tetramethyluronium hexafluorophosphate, 6-chlorobenzotriazole-1,1,3,3-tetramethyluronium hexafluorophosphate or 2-(1H-benzotriazol-L-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate, the molar ratio of intermediate I, intermediate II and catalyst is 1:(1-3):(0.01-10), and the reaction solvent is selected from dichloromethane, acetonitrile, acetone or tetrahydrofuran; The acidic, alkaline or neutral conditions described in step (4) are selected from the conditions in the presence of ethyl acetate hydrochloric acid gas, trifluoroacetic acid, tetraethylammonium fluoride, tetramethylammonium fluoride, triethylamine, trimethylsilyl iodide or pyridine.

8. Use of a compound according to any one of claims 1 to 3 or a pharmaceutical composition according to claim 4 in the preparation of a drug for preventing and / or treating pain or nervous system diseases.

9. The use according to claim 8, characterized in that The medicine is a medicine for preventing and / or treating acute pain, chronic pain, neuropathic pain, inflammatory pain, nociceptive pain, cancer pain, hyperalgesia or visceral pain.

10. The use according to claim 8, characterized in that The medicine is a medicine for preventing and / or treating epilepsy, anxiety, depression, personality disorder, cognitive disorder, affective disorder, neurodegenerative disease, convulsive disease, schizophrenia, insomnia or restless legs syndrome.

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