A compound having synergistic analgesic effect and pharmaceutical composition, preparation method and use thereof

Abstract

The application discloses a small-molecule twin drug compound with synergistic analgesic effect, a pharmaceutical composition, a preparation method and application thereof. The twin drug molecule is formed by covalently connecting a drug A and a drug B, wherein the drug A is nefopam, and the drug B is gamma-aminobutyric acid (GABA) and an analogue thereof, including gabapentin, pregabalin, GABA, methoxycarbonyl-gamma-aminobutyric acid (MGB), and cligabalin. The analgesic efficacy of the twin drug molecule is superior to that of combined administration and single drug, the twin drug molecule can obviously improve various acute and chronic inflammatory pains and relieve peripheral neuropathic pain induced by paclitaxel, has higher anti-inflammatory activity than that of combined administration and single drug, and thus has the potential to treat pain, inflammation and inflammation-related diseases, and can effectively reduce the interaction between drugs and increase the medication compliance of patients.

Description

Technical Field

[0001] This invention relates to a compound with synergistic analgesic effects, its pharmaceutical composition, preparation method, and uses, and more particularly to a small molecule twin compound with synergistic analgesic effects, its pharmaceutical composition, preparation method, and uses. Background Technology

[0002] Pain severely impacts patients' quality of life, making its active and effective treatment crucial. Nefopam is a novel non-opioid, non-steroidal analgesic, unique both chemically and pharmacologically, and unrelated to any currently known analgesics. The exact mechanism of nefopam's analgesic action remains unclear, but current research suggests it primarily acts on pain transmission pathways in the central nervous system. Most researchers believe nefopam, similar to triple receptor (serotonin, norepinephrine, and dopamine) reuptake inhibitors and anticonvulsants, exerts its analgesic effect by inhibiting synaptic uptake of serotonin, norepinephrine, and dopamine, increasing the inhibitory activity of serotonergic and norepinephrine-depressant pathways, and by modulating calcium and sodium ion channels on the glutamate pathway, thereby reducing the activation of postsynaptic glutamate receptors, such as NMDA receptors.

[0003] Gamma-aminobutyric acid (GABA) is the most important and abundant inhibitory neurotransmitter in the human central nervous system. It plays a crucial role in central hyperexcitability associated with nerve injury, acting on inhibitory synapses in the brain by binding to specific transmembrane receptors in the presynaptic and postsynaptic plasma membranes. Increased GABA concentrations in the spinal cord have been reported to induce analgesia, while decreased GABA concentrations lead to neuropathic pain. Studies have shown that exogenous GABA can attenuate the response of pain-excited neurons in the nucleus accumbens of normal rats to noxious stimuli, exhibiting GABA receptor-mediated analgesia, suggesting that GABA receptors, along with other neurotransmitters, participate in regulating the activity of the nucleus accumbens. Furthermore, in a paclitaxel-induced neuropathic pain model, GABA administration reversed the excitability of rats with neuropathic pain in electrophysiological recordings. These results indicate that GABA plays an important role in the regulation of pain responses.

[0004] Gabapentin, pregabalin, melogabalin, and clegabalin belong to the class of gamma-aminobutyric acid (GABA) analogues. Originally used as anticonvulsants, they are now first-line drugs for treating neuropathic pain. Gabapentin, pregabalin, melogabalin, and clegabalin work by acting on presynaptic voltage-gated Ca2+. 2+ The α2δ1 subunit of the channel reduces Ca 2+These drugs induce influx, thereby inhibiting the release of neurotransmitters (such as glutamate and norepinephrine) and reducing neuronal excitability. However, only a portion of patients experience pain relief after treatment with these drugs. In addition, gabapentin, pregabalin, merogalaline, and cligabalin have a range of side effects, such as shortness of breath and ataxia. Studies have shown that combination therapy can reduce the toxic side effects and improve efficacy of these drugs.

[0005] Summary of the Invention

[0006] Purpose of the invention: The first purpose of this 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 the pharmaceutical composition thereof.

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

[0008]

[0009] in, Structural fragments selected from the chemical structures of gabapentin, pregabalin, γ-aminobutyric acid, melogabalin, and clegabalin, excluding the hydrogen atom on the carboxyl group;

[0010] X is selected from halogens or the anodized group 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, and I;

[0014] m is selected from 0 and 1.

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

[0016]

[0017] This invention employs a "multimodal analgesia" strategy, covalently combining nefopam with γ-aminobutyric acid (GABA) and its analogues (gabapentin, pregabalin, melogabalin, or cligabalin) to create a twin drug. Upon entering the body, the synthesized twin drug releases nefopam along with gabapentin, pregabalin, GABA, melogabalin, or cligabalin monotherapy via Hoffmann elimination and hydrolysis. This results in synergistic analgesia through multiple analgesic mechanisms, achieving better analgesic efficacy, reducing dose-related side effects, and better meeting clinical needs. Therefore, twin drugs of the analgesic nefopam with gabapentin, pregabalin, GABA, melogabalin, or cligabalin have broad application prospects for pain treatment.

[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 is an excipient widely used in the pharmaceutical manufacturing industry. Excipients primarily serve to provide a safe, stable, and functional pharmaceutical composition, and may also provide methods for dissolving the active ingredient at a desired rate after administration to a subject, or for promoting effective absorption of the active ingredient after administration to a subject. The pharmaceutical excipient may be an inert filler, or may provide a function such as stabilizing the overall pH of the composition or preventing degradation of the active ingredient. The pharmaceutical excipient may include one or more of the following: binders, suspending agents, emulsifiers, diluents, fillers, granulators, adhesives, disintegrants, lubricants, anti-adhesion agents, flow aids, wetting agents, gelling agents, absorption delay agents, dissolution inhibitors, enhancers, adsorbents, buffers, chelating agents, preservatives, colorants, flavoring agents, and sweeteners.

[0020] The pharmaceutical compositions of the present invention can be prepared using any method known to those skilled in the art, based on the disclosure. For example, conventional mixing, dissolving, granulation, emulsification, grinding, encapsulation, embedding, or lyophilization processes.

[0021] The pharmaceutical compositions of this invention can be administered in any form, including by injection (intravenous), mucosal, oral (solid and liquid formulations), inhalation, ocular, rectal, topical, or parenteral (infusion, injection, implantation, subcutaneous, intravenous, intra-arterial, intramuscular) administration. The pharmaceutical compositions of this invention can also be controlled-release or sustained-release dosage forms (e.g., liposomes or microspheres). Examples of solid oral formulations include, but are not limited to, powders, capsules, tablets, soft capsules, and tablets. Examples of liquid formulations for oral or mucosal administration include, but are not limited to, suspensions, emulsions, elixirs, and solutions. Examples of topical formulations include, but are not limited to, emulsions, gels, ointments, creams, patches, pastes, foams, lotions, drops, or serum preparations. Examples of parenteral formulations include, but are not limited to, solutions for injection, dry powder formulations 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 tablets.

[0022] The method for preparing the compound of the present invention includes the following steps:

[0023]

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

[0025] (2) Use an alkaline reagent to release nefopam hydrochloride into nefopam, and then react the released nefopam with the intermediate. The reaction was carried out by heating in the reaction solvent to obtain intermediate II;

[0026] (3) The intermediate I obtained in step (1) and the intermediate II obtained in step (2) are subjected to a condensation reaction under the action of a catalyst to obtain intermediate III;

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

[0028] Where R1 is selected from the protecting groups Boc, Cbz, Fomc, and Alloc, m, The definition is as described above.

[0029] Preferably, the amino protecting agent mentioned in step (1) is selected from di-tert-butyl dicarbonate (Boc2O), benzooxycarbonyl succinimide (Cbz-Cl), fluorenyl methyl chloroformate (Fmoc-Cl) or allyl chloroformate (Alloc-Cl), and the molar ratio of gabapentin, pregabalin, γ-aminobutyric acid, melogabalin or clegabalin 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, and potassium bicarbonate; the reaction solvent is selected from acetonitrile, acetone, tetrahydrofuran, N,N-diformylformamide, or N,N-diformylacetamide; and nefopam and the intermediate are also selected from these reagents. The molar ratio is 1:(2~10).

[0031] Preferably, the catalyst 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'-tetramethylurea hexafluorophosphate (HBTU), 6-chlorobenzotriazole-1,1,3,3-tetramethylurea hexafluorophosphate (HCTU) or 2-(1H-benzotriazo-L-1-yl)-1,1,3,3-tetramethylurea 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 described in step (4) are selected from the presence of ethyl acetate, hydrochloric acid gas, trifluoroacetic acid, tetraethylamine fluoride, tetramethylamine fluoride, triethylamine, trimethyliodosilane, or pyridine.

[0033] The compounds or pharmaceutical compositions thereof described in this invention are used to prepare remedies for the prevention and / or treatment of pain and nervous system diseases.

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

[0035] Preferably, the drug is a drug for the prevention and / or treatment of epilepsy, anxiety, depression, personality disorders, cognitive impairment, emotional disorders, neurodegenerative diseases, seizure disorders, 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] This invention utilizes medicinal chemistry to covalently link nefopam and γ-aminobutyric acid (GABA) and its analogues, ultimately obtaining a novel molecular entity with high analgesic activity. Its analgesic efficacy is superior to that of combination therapy and monotherapy, significantly improving various acute and chronic inflammatory pains and alleviating paclitaxel-induced peripheral neuropathy. Furthermore, it exhibits higher anti-inflammatory activity than combination therapy and monotherapy. Since treating inflammation is a feasible method for improving pain, the compound designed in this invention has the potential to treat pain, inflammation, and inflammatory pain-related diseases. In addition, it can effectively reduce drug interactions and increase patient medication adherence. Attached Figure Description

[0039] Figure 1 The 1H NMR spectrum of compound 3;

[0040] Figure 2 The 1H NMR spectrum of compound 4;

[0041] Figure 3 The carbon NMR spectrum of compound 3;

[0042] Figure 4 The carbon NMR spectrum of compound 4;

[0043] Figure 5 This diagram illustrates the analgesic effect of nefopam in a carrageenan-induced inflammatory pain model. A represents the analgesic time-efficacy curve of nefopam in carrageenan-treated mice, B represents the time-efficacy relationship represented by an AUC plot, and C represents the effect-efficacy (ED) of nefopam in carrageenan-induced inflammatory pain in mice. 50 value;

[0044] Figure 6 This diagram illustrates the analgesic effect of nefopam in an iodoacetic acid-induced osteoarthritis pain model. A represents the analgesic time-efficacy curve of nefopam in mice treated with iodoacetic acid, B represents the time-efficacy relationship represented by an AUC plot, and C represents the effect-efficacy of nefopam in mice with iodoacetic acid-induced osteoarthritis pain. 50 value;

[0045] Figure 7 This diagram illustrates the analgesic effect of nefopam in a paclitaxel-induced neuropathic pain model. A represents the analgesic time-efficacy curve of nefopam in paclitaxel-treated mice, B represents the time-efficacy relationship represented by an AUC plot, and C represents the effect-efficacy curve of nefopam in paclitaxel-induced neuropathic pain mice. 50 value;

[0046] Figure 8This diagram illustrates the analgesic effect of pregabalin / gabapentin in a carrageenan-induced inflammatory pain model. A and C represent the analgesic time-effect curves of pregabalin / gabapentin in carrageenan-treated mice, B and D represent the time-effect relationship of pregabalin / gabapentin as represented by the AUC plot, and E and F represent the end-efficacy (ED) of pregabalin / gabapentin in carrageenan-induced inflammatory pain in mice. 50 value;

[0047] Figure 9 This diagram illustrates the analgesic effect of pregabalin / gabapentin in an iodoacetic acid-induced osteoarthritis pain model. A and C represent the analgesic time-effect curves of pregabalin / gabapentin in iodoacetic acid-treated mice, B and D represent the time-effect relationship of pregabalin / gabapentin as represented by an AUC plot, and E and F represent the end-efficacy (ED) of pregabalin / gabapentin in iodoacetic acid-induced osteoarthritis pain in mice. 50 value;

[0048] Figure 10 This diagram illustrates the analgesic effect of pregabalin / gabapentin in a paclitaxel-induced neuropathic pain model. A and C represent the analgesic time-effect curves of pregabalin / gabapentin in paclitaxel-treated mice, respectively; B and D represent the time-effect relationship of pregabalin / gabapentin as shown by the AUC plot; and E and F represent the effect of pregabalin / gabapentin on the effects of paclitaxel-induced neuropathic pain in mice. 50 value;

[0049] Figure 11 This diagram illustrates the analgesic effects of compounds 3 and 4 in a carrageenan-induced inflammatory pain model. A and C represent the time-effect curves of analgesia for compounds 3 and 4 in carrageenan-treated mice, respectively. B and D represent the time-effect relationship of compounds 3 and 4 as shown in the AUC plot. E and F represent the end-efficacy (ED) of compounds 3 and 4 in carrageenan-induced inflammatory pain in mice, respectively. 50 value;

[0050] Figure 12 This diagram illustrates the analgesic effects of compounds 3 and 4 in an iodoacetic acid-induced osteoarthritis pain model. A and C represent the time-effect curves of analgesia for compounds 3 and 4 in iodoacetic acid-treated mice, respectively; B and D represent the time-effect relationship of compounds 3 and 4 represented by AUC plots; and E and F represent the end-efficacy (ED) of compounds 3 and 4 in iodoacetic acid-induced osteoarthritis pain in mice, respectively. 50 value;

[0051] Figure 13This diagram illustrates the analgesic effects of compounds 3 and 4 in a paclitaxel-induced neuropathic pain model. A and C represent the time-effect curves of analgesia for compounds 3 and 4 in paclitaxel-treated mice, respectively; B and D represent the time-effect relationship of compounds 3 and 4 as represented by the AUC plot; and E and F represent the effect-effect curves of compounds 3 and 4 in paclitaxel-induced neuropathic pain mice, respectively. 50 value;

[0052] Figure 14 This is a schematic diagram showing the motion coordination of compounds 3 and 4 in a rotator experiment. Detailed Implementation

[0053] The technical solution of the present invention will be further described below with reference to the embodiments.

[0054] The structures of the compounds in 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 with deuterated dimethyl sulfoxide (DMSO-d6) as the solvent, deuterated chloroform (CDCl3) as the internal standard, and tetramethylsilane (TMS).

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

[0056] Thin-layer chromatography (TLC) uses Yantai Huanghai HSGF254 or Qingdao GF254 silica gel plates. The silica gel plates used in TLC have a diameter of 0.15–0.2 mm, while the diameter of the plates used for TLC separation and purification is 0.4–0.5 mm.

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

[0058] Unless otherwise specified in the examples, the reaction temperature is room temperature, which is 20-30°C.

[0059] The reaction process in the examples was monitored using 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-bromoonium hydrochloride (Compound 1)

[0061] The synthesis 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]oxazine-5-bromoonium (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. 2-bromoethanol (5.0 g, 40 mmol, 2.0 eq) was added with 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 excess solvent was removed using a rotary evaporator. 60 mL of ethyl acetate was added, and the mixture was stirred and stirred for 1 hour. The mixture was filtered and dried to obtain 6.5 g of a pale yellow solid, yielding 1A, with a yield of 85.5%. (+)-ESI-MS: m / z 298.1812 (calcd.298.1802 for C 19 H 24 NO2 + [M-Br] + ).

[0065] Step 2: Synthesis of (S)-3-(((tert-Butoxycarbonyl)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 dropwise. While stirring, a mixed solution of di-tert-butyl dicarbonate (2.65 g, 12 mmol, 1.2 eq) and dioxane (25 mL) was added dropwise. After stirring at room temperature for 2 hours, TLC monitoring showed that the 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 the pH was adjusted to 4-5 with NaHCO3. Dichloromethane (3 × 20 mL) was added for extraction again. The organic layers were combined, washed with 15 mL of saturated brine, dried over anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 2.11 g of 1B as a white solid powder, 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 NO4 + [M+H] + ).

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

[0068] In a 100 mL round-bottom flask, add 20 mL of dichloromethane, 1A (0.76 g, 2 mmol, 1.0 eq), 1B (0.62 g, 2.4 mmol, 1.2 eq), and DMAP (0.024 g, 0.2 mmol, 0.1 eq). After stirring, add EDCI (0.46 g, 2.4 mmol, 1.2 eq) and react at room temperature. Monitor the reaction process by TLC. After 3 hours, 1A was almost completely reacted. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate. After extraction, the organic layer was adjusted to pH 5-6 with 1 mol / L hydrochloric acid, and extracted again. The organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL). Finally, it was dried with anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 1.3 g of crude product as a yellow oil. The crude product was purified by chromatographic column (DCM:MeOH = 15:1) to obtain 0.86 g of 1C as a pale yellow oil, with a yield of 69.6%. (+)-ESI-MS: m / z 539.3492 (calcd. 539.3479 for C 32 H 47 N2O5 + [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]oxazine-5-bromoonium hydrochloride (Compound 1)

[0070] In a 100 mL round-bottom flask, 0.86 g of product 1C from step 3 was added and dissolved in ethyl acetate (with a small amount of methanol added dropwise). While stirring, a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise. The mixture was stirred at room temperature, and the reaction was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 1C was basically completely reacted. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain 0.6 g of white solid (compound 1), with a yield of 77.9%. 1 H NMR (500MHz, DMSO-d6) 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),7.2 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). 13C NMR(126MHz,DMSO-d6)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 N2O3 + [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]oxazine-5-bromoonium hydrochloride (compound 2)

[0072] The synthesis route is as follows:

[0073]

[0074] Step 1: Synthesis of 2-(1-((tert-Butoxycarbonyl)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 dropwise. While stirring, a mixed solution of di-tert-butyl dicarbonate (2.65 g, 12 mmol, 1.2 eq) and dioxane (25 mL) was added dropwise. After stirring at room temperature for 2 hours, TLC monitoring showed 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 the pH was adjusted to 4-5 with NaHCO3. Dichloromethane (3 × 20 mL) was added for extraction again. The organic layers were combined, washed with 15 mL of saturated brine, dried over anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 2.25 g of 2B as a white solid powder, with a yield of 83.3%. (+)-ESI-MS: m / z 272.1866 (calcd. 272.1856 for C 14 H26 NO4 + [M+H] + ).

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

[0077] In a 100 mL round-bottom flask, add 20 mL of dichloromethane, 1A (0.76 g, 2 mmol, 1.0 eq), 2B (0.65 g, 2.4 mmol, 1.2 eq), and DMAP (0.024 g, 0.2 mmol, 0.1 eq). After stirring, add EDCI (0.46 g, 2.4 mmol, 1.2 eq) and react at room temperature. Monitor the reaction process by TLC. After 3 hours, 1A was almost completely reacted. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate. After extraction, the organic layer was adjusted to pH 5-6 with 1 mol / L hydrochloric acid, and extracted again. The organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL). Finally, it was dried with anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 1.5 g of crude product as a yellow oil. The crude product was purified by chromatographic column (DCM:MeOH = 15:1) to obtain 0.95 g of 2C as a pale yellow oil, with a yield of 75.4%. (+)-ESI-MS: m / z 551.3491 (calcd.551.3479 for C) 33 H 47 N2O5 + [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]oxazine-5-bromoonium hydrochloride (compound 2)

[0079] In a 100 mL round-bottom flask, 0.95 g of product 2C from step three was added and dissolved in ethyl acetate (with a small amount of methanol added dropwise). While stirring, a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise. The mixture was stirred at room temperature, and the reaction was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 2C was basically completely reacted. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain 0.7 g of white solid (compound 2), with a yield of 82.3%. 1H NMR (500MHz, 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=11.2Hz,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(126MHz,DMSO-d6)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 N2O3 + [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-bromoonium hydrochloride (compound 3)

[0081] The synthesis 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]oxazine-5-bromoonium (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. 3-bromo-1-propanol (5.56 g, 40 mmol, 2.0 eq) was added with 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 excess solvent was removed using a rotary evaporator. 60 mL of ethyl acetate was added, and the mixture was stirred and stirred for 1 hour. The mixture was filtered and dried to obtain 6.7 g of a pale red solid, yielding 2A, with a yield of 85.9%. (+)-ESI-MS m / z 312.1966 (calcd. 312.1958 for C 20 H 26 NO2 + [M-Br] + ).

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

[0086] In a 100 mL round-bottom flask, add 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). After stirring, add EDCI (0.46 g, 2.4 mmol, 1.2 eq) and react at room temperature. Monitor the reaction process by TLC. After 3 hours, reaction 2A was almost complete. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate, extracted, and the organic layer was adjusted to pH 5-6 with 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). Finally, it was dried with anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 1.35 g of crude product as a yellow oil. The crude product was purified by chromatographic column (DCM:MeOH = 15:1) to obtain 0.91 g of 3C as a pale yellow oil, with a yield of 72.2%. (+)-ESI-MS: m / z 553.3649 (calcd. 553.3636 for C 33 H 49 N2O5 + [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]oxazine-5-bromoonium hydrochloride (compound 3)

[0088] In a 100 mL round-bottom flask, 0.91 g of product 3C from step 3 was added and dissolved in ethyl acetate (with a small amount of methanol added dropwise). While stirring, a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise. The mixture was stirred at room temperature, and the reaction was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 3C was basically completely reacted. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain 0.62 g of white solid (compound 3), with a yield of 75.6%. 1 H NMR (500MHz, DMSO-d6) 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),2.43-2.3 2(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). 13C NMR(126MHz,DMSO-d6)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 / 124.8 3,85.32 / 84.98,65.81,65.05 / 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 N2O3 + [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-bromoonium hydrochloride (compound 4)

[0090] The synthesis route is as follows:

[0091]

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

[0093] In a 100 mL round-bottom flask, add 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). After stirring, add EDCI (0.46 g, 2.4 mmol, 1.2 eq) and react at room temperature. Monitor the reaction process by TLC. After 3 hours, reaction 2A was almost complete. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate, extracted, and the organic layer was adjusted to pH 5-6 with 1 mol / L hydrochloric acid, extracted again, and washed once with water (10 mL) and once with saturated saline solution (10 mL). Finally, it was dried with anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 1.45 g of crude product as a yellow oil. The crude product was purified by chromatographic column (DCM:MeOH = 15:1) to obtain 0.99 g of 4C as a pale yellow oil, with a yield of 77.3%. (+)-ESI-MS: m / z 565.3652 (calcd.565.3636 for C 34 H 49 N2O5 + [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]oxazine-5-bromoonium hydrochloride (compound 4)

[0095] In a 100 mL round-bottom flask, 0.99 g of product 4C from step 3 was added and dissolved in ethyl acetate (with a small amount of methanol added dropwise). While stirring, a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise. The mixture was stirred at room temperature, and the reaction was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 4C was basically completely reacted. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain 0.73 g of white solid (compound 4), with a yield of 84.2%. 1H NMR (500MHz, DMSO-d6) 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-d6)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 N2O3 + [M-Br] + ).

[0096] Example 5: Synthesis of 5-(2-((4-aminobutyryl)oxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazine-5-bromoonium hydrochloride (compound 5)

[0097] The synthesis route is as follows:

[0098]

[0099] Step 1: Synthesis of 4-(tert-Butoxycarbonyl)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 dropwise. While stirring, a mixed solution of di-tert-butyl dicarbonate (2.65 g, 12 mmol, 1.2 eq) and dioxane (25 mL) was added dropwise. After stirring at room temperature for 2 hours, TLC monitoring showed 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 the pH was adjusted to 4-5 with NaHCO3. Dichloromethane (3 × 20 mL) was added for extraction again. The organic layers were combined, washed with 15 mL of saturated brine, dried with anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 1.6 g of 3B as a white solid powder, 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 C9H 18 NO4 + [M+H] + ).

[0101] Step 2: Synthesis of 5-(2-((4-((tert-butoxycarbonyl)amino)butyryl)oxy)ethyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazine-5-bromoonium (5C)

[0102] In a 100 mL round-bottom flask, add 20 mL of dichloromethane, 1A (0.76 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). After stirring, add EDCI (0.46 g, 2.4 mmol, 1.2 eq) and react at room temperature. Monitor the reaction process by TLC. After 3 hours, 1A was almost completely reacted. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate. After extraction, the organic layer was adjusted to pH 5-6 with 1 mol / L hydrochloric acid, and extracted again. The organic layer was washed once with water (10 mL) and once with saturated saline solution (10 mL). Finally, it was dried with anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 1.1 g of crude product as a yellow oil. The crude product was purified by chromatographic column (DCM:MeOH = 15:1) to obtain 0.74 g of 5C as a pale yellow oil, with a yield of 66.1%. (+)-ESI-MS: m / z 483.2867 (calcd.483.2853 for C 28 H 39 N2O5 + [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]oxazine-5-bromoonium hydrochloride (compound 5)

[0104] In a 100 mL round-bottom flask, 0.74 g of product 5C from step 3 was added and dissolved in ethyl acetate (with a small amount of methanol added dropwise). While stirring, a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise. The mixture was stirred at room temperature, and the reaction was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 5C was basically completely reacted. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain 0.55 g of white solid (compound 5), with a yield of 84.6%. 1H NMR (500MHz, DMSO-d6) 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 N2O3 + [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]oxazine-5-bromoonium hydrochloride (compound 6)

[0106] The synthesis route is as follows:

[0107]

[0108] Step 1: Synthesis of 5-(3-((4-((tert-butoxycarbonyl)amino)butyryl)oxy)propyl)-5-methyl-1-phenyl-3,4,5,6-tetrahydro-1H-benzo[f][1,4]oxazine-5-bromoonium (6C)

[0109] In a 100 mL round-bottom flask, add 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). After stirring, add EDCI (0.46 g, 2.4 mmol, 1.2 eq) and react at room temperature. Monitor the reaction process by TLC. After 3 hours, reaction 2A was almost complete. The reaction solution was adjusted to pH 9-10 with saturated sodium bicarbonate, extracted, and the organic layer was adjusted to pH 5-6 with 1 mol / L hydrochloric acid, extracted again, and washed once with water (10 mL) and once with saturated saline solution (10 mL). Finally, it was dried with anhydrous sodium sulfate, filtered, and evaporated to dryness to obtain 1.09 g of crude product as a yellow oil. The crude product was purified by chromatographic column (DCM:MeOH = 15:1) to obtain 0.81 g of 3C as a pale yellow oil, with a yield of 70.4%. (+)-ESI-MS: m / z 497.3035 (calcd.497.3010 for C 29 H 41 N2O5 + [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]oxazine-5-bromoonium hydrochloride (compound 6)

[0111] In a 100 mL round-bottom flask, 0.81 g of product 6C from step 3 was added and dissolved in ethyl acetate (with a small amount of methanol added dropwise). While stirring, a saturated ethyl acetate / HCl solution (adjusted to pH 2-4) was added dropwise. The mixture was stirred at room temperature, and the reaction was monitored by TLC. A large amount of white solid precipitated during the reaction. After 2 hours, 6C was basically completely reacted. The mixture was filtered, and the filter cake was dried under reduced pressure to obtain 0.68 g of white solid (compound 6), with a yield of 94.4%. 1H NMR(500MHz,DMSO-d6)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=7.2Hz,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=13.4 Hz,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 -2.10(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 N2O3 + [M-Br] + ).

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

[0113] Carrageenan-induced inflammatory pain is a widely used animal model for assessing acute inflammatory pain. λ-carrageenan, a sulfated polysaccharide extracted from red algae, induces local inflammatory responses in animals, such as tissue swelling, congestion, and hyperalgesia. In mice, inflammatory pain induced by a paw injection of 20 μL of 1% carrageenan solution peaked at 3 hours and subsided within 24–72 hours. After modeling, the mechanical withdrawal threshold in mice was significantly lower than baseline, indicating successful induction of inflammatory pain. As shown in the figure, nefopam (1, 3, 5, 10 mg / kg) dose-dependently reduced carrageenan-induced inflammatory pain [F(35, 210) = 21.56, p < 0.0001, ] Figure 5 A; F(4,25)=31.11, p<0.0001, Figure 5 [B] The analgesic and inhibitory rates of nefopam at doses of 1, 3, 5, and 10 mg / kg in inflammatory pain were 36.27%, 59.18%, 77.00%, and 93.15%, respectively, with an ED50 of 50%. 50 The concentration was 1.80 ± 0.59 mg / kg. Figure 5 ).

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

[0115] Osteoarthritis is a chronic degenerative joint disease clinically 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. After injecting 20 μL of 1% iodoacetic acid into the knee joint of mice for 24 hours, the mechanical withdrawal threshold was significantly reduced, indicating a successful establishment of an osteoarthritis pain model. 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 The result was AUC[F(4, 25) = 82.32, p < 0.0001, A]. Figure 6 [B] In iodoacetic acid-induced osteoarthritis pain, the analgesic inhibition rates of nefopam at four doses (3, 10, 30, and 60 mg / kg) were 16.00%, 30.02%, 45.99%, and 57.27%, respectively, with an ED50% (half-maximal effective dose). 50 The value was 38.11 ± 2.08 mg / 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 atopic pain and hyperalgesia induced by harmful or harmless stimuli. On day 6, compared with baseline, the mechanical withdrawal threshold of mice in the model group was significantly reduced, indicating that paclitaxel-induced neuropathic pain in mice was successfully established. Nefopam (1, 3, 5, 10 mg / kg) reversed paclitaxel-induced mechanical atopic pain in a dose-dependent manner, with analgesic efficacy reaching its 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 efficacy of nefopam was determined by dose-response curves. 50 The values ​​were 2.40 ± 0.57 mg / kg, and the analgesic inhibition rates were 35.92%, 49.89%, 63.11%, and 81.02%, respectively. Figure 7 ).

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

[0119] λ-Carrageenan is a chemical substance that stimulates inflammation by releasing pro-inflammatory factors, including prostaglandins, leukotrienes, histamine, serotonin, bradykinin, and TNF-α. In mice, a paw injection of 20 μL of 1% carrageenan solution induced a local inflammatory response (peaking at 3 hours and subsiding within 24–72 hours), such as tissue swelling, hyperemia, and hyperalgesia. Three hours after carrageenan injection, the mechanical withdrawal threshold in mice was significantly lower than baseline, indicating successful induction of inflammatory pain. As shown in the figure, pregabalin (3, 6, 12, 24 mg / kg) and gabapentin (25, 50, 75, 100 mg / kg) both reduced carrageenan-induced inflammatory pain 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 and inhibitory rates of pregabalin at doses of 3, 6, 12, and 24 mg / kg in inflammatory pain were 29.26%, 46.86%, 64.06%, and 80.48%, respectively, with an ED50 of 60%. 50 The analgesic and inhibitory rates of gabapentin at doses of 6.80 ± 1.01 mg / kg were 16.15%, 47.20%, 67.86%, and 80.76% in inflammatory pain, respectively, with a median effective dose (ED50) of 6.80 ± 1.01 mg / kg. 50 The concentration was 52.80 ± 1.10 mg / kg. Figure 8 ).

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

[0121] Joint pain is a major clinical feature of osteoarthritis, primarily caused by synovial neuroinflammation and subchondral nerve damage. With the occurrence of joint injury, pain develops and gradually leads to loss of joint mobility in osteoarthritis patients. Iodoacetic acid-induced osteoarthritis models have become one of the most popular models for studying the pain process and intervention effects in osteoarthritis, allowing for the assessment of not only the analgesic effects of drugs but also their anti-inflammatory effects. In mice, a significant reduction in the mechanical withdrawal threshold was observed 24 hours after injection of 20 μL of 1% iodoacetic acid into the knee joint, indicating successful establishment of the osteoarthritis pain model. Pregabalin (6, 12, 24, 48 mg / kg) and gabapentin (25, 50, 75, 100 mg / kg) showed significant dose-dependent analgesic effects in the osteoarthritis pain model [F(35, 210) = 65.30, p < 0.0001, ] Figure 9 A; F(35,210)=82.29, p<0.0001, Figure 9 C], the result is AUC[F(4,25)=80.38, p<0.0001, Figure 9 B; F(4,25)=239.90, p<0.0001, Figure 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, with an ED50% (half-maximal effective dose). 50 The analgesic inhibition rate of gabapentin at four doses (25, 50, 75, and 100 mg / kg) was 23.00%, 45.77%, 61.14%, and 70.00%, respectively, with an ED50% of 14.90 ± 1.09 mg / kg. 50 The concentration was 56.00 ± 30.20 mg / kg. Figure 9 ).

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

[0123] Some evidence suggests that hyperexcitability of dorsal root ganglia and spinal dorsal horn neurons may lead to the development of thermal and mechanosensitive hypersensitivity in animal models of neuropathic pain induced by chemotherapy drugs such as paclitaxel, vincristine, and cisplatin. On day 6, the mechanosensitive withdrawal threshold was significantly reduced in the model group mice compared to baseline, indicating successful establishment of paclitaxel-induced neuropathic pain in mice. Pregabalin (3, 6, 12, 24 mg / kg) dose-dependently reversed paclitaxel-induced mechanosensitive pain, and the analgesic efficacy peaked at 90 minutes post-administration [F(35, 210) = 28.31, p < 0.0001]. Figure 10 A; F(4,25)=114.00, p<0.0001, Figure 10 B]. Gabapentin (25, 50, 75, 100 mg / kg) also reversed mechanical atopic pain in a dose-dependent manner, with peak analgesic efficacy at 120 minutes post-administration [F(35, 210) = 29.15, p < 0.0001, Figure 10 C; F(4,25)=70.95, p<0.0001, Figure 10 D]. The median effective dose (ED) of pregabalin and gabapentin was obtained through dose-response curves. 50The values ​​were 7.50±2.23 mg / kg and 45.60±0.20 mg / 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%, respectively. Figure 10 ).

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

[0125] Three hours after injection of carrageenan into the plantar surface of mice, the mechanical withdrawal threshold was significantly lower than baseline, indicating successful induction of inflammatory pain. Administration of compounds 3 and 4 significantly increased the mechanical withdrawal threshold in mice [F(24, 150) = 86.65, p < 0.0001]. Figure 11 A; F(3,20)=100.20, p<0.0001, Figure 11 C]. Both conjugated drugs produced dose-dependent analgesic effects in mice [F(24, 150) = 84.46, p < 0.0001, Figure 11 B; F(3,20)=188.20, p<0.0001, Figure 11 [D]. The analgesic and inhibitory rates of compounds 3 and 4 were 79.16%, 70.46%, and 57.31%, and 93.51%, 69.84%, and 43.09%, respectively, with an ED50 of 100%. 50 The median effective doses (EDS) for compounds 3 and 4 in the inflammatory pain model were 0.52 ± 0.29 mg / kg and 5.95 ± 0.83 mg / kg, respectively. 50 Lower than the ED of 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 compounds 3 and 4 in an iodoacetic acid-induced osteoarthritis pain model

[0127] After administration of compounds 3 and 4, the mechanical withdrawal threshold in mice was significantly increased [F(24, 150) = 84.40, p < 0.0001, Figure 12 A; F(24,150)=38.38, p<0.0001, Figure 12 C]. Both conjugated drugs produced significant, dose-dependent analgesic effects in mice [F(3,20)=85.38, p<0.0001, Figure 12 B; F(3,20)=122.00, p<0.0001, Figure 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, while those 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 compounds 3 and 4 was [not specified]. 50 The values ​​were 3.41±1.16 and 5.03±0.26 mg / kg, respectively.

[0128] Both conjugate compounds 3 and 4 exhibited improved analgesic activity in a mouse model of osteoarthritis pain, with the half-maximal effective dose (ED50) of the conjugates significantly lower than that of the combined administration. 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) decreased by 3.17-fold; Compound 4 (24.92±6.93 mg / kg) decreased by 4.95-fold. The half-maximal effective dose (ED50) of nefopam monotherapy in this model was significantly reduced. 50 The concentration was 38.11 mg / kg. The synthesis of the conjugate drug compensated for the insufficient efficacy of nefopam monotherapy in treating osteoarthritis pain.

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

[0130] After successful establishment of paclitaxel-induced neuropathic pain in mice, the mechanical withdrawal threshold of the model group mice was significantly reduced. Compounds 3 and 4, administered at doses of 1, 5, and 10 mg / kg, respectively, significantly improved paclitaxel-induced neuropathic pain, with analgesic efficacy showing a dose-dependent effect [F(24, 150) = 84.40, p < 0.0001]. Figure 13 A; F(3,20)=60.51, p<0.0001, Figure 13 B; F(24,150)=36.79, p<0.0001, Figure 13 C; F(3,20)=80.61, p<0.0001, Figure 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, with an ED50% (half-maximal effective dose). 50 The concentration was 1.38 ± 0.05 mg / kg. 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, with an ED50 of 1.38 ± 0.05 mg / kg. 50 The effective dose was 5.28 ± 0.15 mg / kg. The conjugates 3 and 4 demonstrated improved analgesic efficacy in a neuropathic pain model, with an ED50% (half-maximal effective dose) of 5.28 ± 0.15 mg / kg. 50 The ED is much lower than that of combined administration. 50 (The synergistic anti-nociceptive effects of nefopam and gabapentinoidsin inflammatory, osteoarthritis, and neuropathic pain in mouse models. European Journal of Pharmacology 977(2024)176738. Nefopam + pregabalin: 4.95 mg / kg; Nefopam + gabapentin: 24.00 mg / kg).

[0131] Example 16: Motion coordination of compounds 3 and 4 in rotator bar experiments

[0132] The fatigue rotundus test is a classic method for assessing the effects of drugs on animal behavior. Because pregabalin / gabapentin has an ED50% (half-maximal effective dose)... 50 Drug administration affects the motor coordination ability of mice. This invention evaluates the effect of compound 3 (3.41 mg / kg, the highest ED among three models) using this experiment. 50 (dose) and compound 4 (5.95 mg / kg, the highest ED among the three models) 50 The effect of dosage on sedation or motor dysfunction in mice. Experimental results showed that the half-maximal effective dose (ED) of ED... 50 The drop latency in mice after administration was not significantly different from that in the control group. Figure 14 This indicates that the conjugate compounds 3 and 4 do not cause ataxia or sedation.

[0133] Example 17: Safety of Compounds 3 and 4 in Acute Toxicity Tests

[0134] Acute toxicity tests are used to determine the median lethal acute LD50 shortly after administration. 50 And the adverse reactions caused. Mice were observed for 7 days after gavage administration of conjugate compound 3 (2000 mg / kg), compound 4 (2000 mg / kg) or physiological saline. After 7 days, no mice in the treated group or the blank group died, and no obvious adverse reactions were observed.

[0135] In summary, conjugates of nefopam and gamma-aminobutyric acid (GABA) analogs are highly effective and low in toxicity, providing a new approach for clinical analgesia. Compared to traditional compound preparations and combination therapies, conjugates can effectively reduce drug interactions, eliminate the need to consider dosage ratios, are more convenient to take, increase patient compliance, and improve patients' quality of life.

Claims

1. A compound with synergistic analgesic effect, characterized in that, The chemical structure of the compound is as follows: ， in, Selected from , , ; X is selected from halogens or the anodized group 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 aforementioned chemical structure, X is selected from F, Cl, Br, and 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, It contains the compound as described in 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 the protecting groups Boc, Cbz, Fomc, and Alloc, m, As defined in claim 1, the preparation method comprises the following steps: ， (1) Protect the amino groups in the structures of gabapentin, pregabalin, and γ-aminobutyric acid to obtain intermediate I; (2) Use an alkaline reagent to release nefopam hydrochloride into nefopam, and then react the released nefopam with the intermediate. The reaction was carried out by heating in the reaction solvent to obtain intermediate II; (3) The intermediate I obtained in step (1) and the intermediate II obtained in step (2) are subjected to a condensation reaction under the action of a catalyst to obtain intermediate III; (4) Remove the protecting group from 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 and amino protecting agent in step (1) is 1:(1~10). The alkaline reagent mentioned in step (2) is selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, sodium bicarbonate, and potassium bicarbonate; the reaction solvent is selected from acetonitrile, acetone, tetrahydrofuran, etc. N,N -Diformylformamide or N,N - Dicarboxyacetamide, Nefopam and intermediates The molar ratio is 1:(2~10).

7. The preparation method according to claim 5, characterized in that, The catalyst mentioned 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' -Tetramethylurea hexafluorophosphate, 6-chlorobenzotriazole-1,1,3,3-tetramethylurea hexafluorophosphate or 2-(1 H (-benzotriazo-L-1-yl)-1,1,3,3-tetramethylurea tetrafluoroborate, 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; The acidic, alkaline, or neutral conditions described in step (4) are selected from the presence of ethyl acetate, hydrochloric acid gas, trifluoroacetic acid, tetraethylamine fluoride, tetramethylamine fluoride, triethylamine, trimethyliodosilane, 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 medicament for the prevention and / or treatment of pain and nervous system diseases.

9. The use according to claim 8, characterized in that, The medication described is for the prevention and / or treatment of 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 medications mentioned are for the prevention and / or treatment of epilepsy, anxiety disorders, depression, personality disorders, cognitive impairment, emotional disorders, neurodegenerative diseases, seizure disorders, schizophrenia, insomnia, or restless legs syndrome.

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