Drug conjugates, methods for their preparation, and uses thereof

Abstract

A drug conjugate or a pharmaceutically acceptable salt thereof is prepared by coupling gabapentin or a derivative thereof with propofol or a derivative thereof. Compared with the parent drug, the water solubility and bioavailability of the drug conjugate are effectively improved, and the toxicity and side effects of the drug are reduced. Such a drug conjugate has pharmaceutical effects and can be used to treat and / or prevent central nervous system disorders, such as convulsions / epilepsy, migraine, pain, and depression.

Description

[Technical field]

[0001] The present invention relates to a class of Drug-Drug Conjugates, more particularly to the preparation of the drug conjugates formed by Propofol (or its derivatives) and Gabapentin (or its derivatives), their salts, and crystallization methods. The present invention also relates to the use of said drug conjugates and their salts in the treatment or prevention of central nervous system disorders, such as convulsions / epilepsy, migraine, and depression. [Background technology]

[0002] Drug conjugates are a proven approach to new drug innovation. Drug conjugates are novel molecular entities formed by covalently linking two or more biologically active single drugs. The main purpose of this design is to avoid most of the limitations of single drugs in clinical use. Compared with traditional drugs, drug conjugates have several special advantages, including improved solubility, improved bioavailability, extended half-life and therapeutic period, reduced toxicity, and reduced drug resistance.

[0003] Propofol and gabapentin are both FDA approved active compounds that are very useful for the treatment or prevention of central nervous system disorders. Propofol is an intravenous short-acting anesthetic agent that is widely used for the induction and maintenance of anesthesia. Compared with other anesthetic agents, propofol has the advantages of rapid onset of action, high clearance rate, rapid awakening, and complete recovery of neurophysiological function. In addition, various pharmacological effects of propofol have been shown to be useful for the treatment of various clinical conditions, including migraine, nausea, pain, and anxiety. However, propofol has very low oral bioavailability due to limited water solubility, poor pharmacokinetic properties, and hepatic first-pass effect, making it difficult to achieve the lowest effective dose of the drug, which prevents its widespread clinical application, especially in the central nervous system. Gabapentin is a compound structurally similar to the neurotransmitter gamma-aminobutyric acid (GABA). It is primarily used to treat neuropathic pain and as an adjunctive treatment for partial epileptic seizures in adults with epilepsy. Clinical trials have shown gabapentin's potential role in the treatment of restless leg syndrome, anxiety, and other neurological disorders. However, gabapentin is highly polar and has poor lipid solubility, making it difficult to penetrate the blood-brain barrier, and is prone to dose saturation during clinical use, resulting in dose-dependent kinetics that significantly limit the application of gabapentin in other central nervous system disorders.

[0004] To date, in the process of exploring new applications of propofol and gabapentin in central nervous system diseases, there have been many studies on improving the pharmacokinetics of these two compounds, many of which have been achieved by improving the pharmacokinetics of these two compounds, designing or formulating prodrugs (e.g., non-emulsion formulations of propofol using cyclodextrins and micelles, amino acid ester and phosphate ester derivatives of propofol, Schiff base of gabapentin), but they have only limited success. Propofol and gabapentin each have complex pharmacological mechanisms of action and very different pharmacokinetic profiles, making it difficult to administer the two active substances in a single pharmaceutical formulation. When attempting to combine propofol and gabapentin in two different formulations, the ideal synergistic effect of the two drugs to improve efficacy was not observed.

[0005] The application of drug-drug conjugates provides another completely new way to overcome the limitations of propofol and gabapentin in the pharmacokinetics of the two active substances, and to find and improve their new applications in the prevention and treatment of central nervous system diseases. A new molecular entity can be made by coupling propofol and gabapentin in a stable covalent form, effectively improving the hydrophilic and lipophilic nature of the original two synthon active groups, improving the pharmacokinetic properties of both, and further making the drug easier to formulate and reducing toxicity and side effects. As a new molecular entity, the newly obtained conjugate can exert pharmacological effects in vivo, and the pharmacological mechanism of action can be completely different from that of propofol and gabapentin, thus developing its new application in central nervous system diseases. Summary of the Invention [Means for solving the problem]

[0006] The object of the present invention is to provide a class of propofol-gabapentin drug conjugates and methods for their preparation and use. A first aspect of the present invention provides a drug conjugate or a pharma- ceutically acceptable salt thereof, The structure of the drug conjugate is shown in formula (I): D p -LD g (I) (In the formula, D g is gabapentin or a derivative thereof; L is selected from a carbonyl group or may be absent; D p is selected from propofol and its derivatives; Preferably, the structure of the pharma- ceutically acceptable salt of the drug conjugate is shown in formula (II): D p -LD g A (II) (wherein A is a pharma- ceutically acceptable acidic anion, preferably selected from one or more of the following: sulfate, phosphate, hydrochloride, hydrobromide, acetate, oxalate, citrate, succinate, gluconate, tartrate, p-toluenesulfonate, benzenesulfonate, and mesylate).

[0007] D g is gabapentin or a derivative thereof as shown in formula (III) or a pharma- ceutically acceptable salt thereof according to the first aspect of the present invention:

[0008] [ka]

[0009] (wherein R1 is a methyl group or a hydrogen atom).

[0010] D g is gabapentin or a derivative thereof as shown in formula (IV) or a pharma- ceutically acceptable salt thereof according to the first aspect of the present invention:

[0011] [ka]

[0012] (wherein R2 and R3 are independently selected from a methyl group and a hydrogen atom).

[0013] D g is a derivative of gabapentin represented by formula (V) or a pharma- ceutically acceptable salt thereof according to the first aspect of the present invention:

[0014] [ka]

[0015] (wherein R4, R5 and R6 are independently selected from a methyl group and a hydrogen atom).

[0016] D p is propofol or a derivative thereof as shown in formula (VI) or a pharma- ceutically acceptable salt thereof according to the first aspect of the present invention:

[0017] [ka]

[0018] (wherein X is a halogen atom or a hydrogen atom).

[0019] A second aspect of the present invention provides a method for preparing a drug conjugate or a pharma- ceutically acceptable salt thereof according to the first aspect, comprising: The method includes preparing a drug conjugate by suspending Dp and Dg in an organic solvent; The organic solvent is preferably selected from one or more of dichloromethane, tetrahydrofuran / water, diethyl ether, methanol, ethanol, isopropanol, benzene, and toluene; preferably dichloromethane and / or tetrahydrofuran / water.

[0020] Derivatives of gabapentin according to formula (VII) g The method includes the steps of:

[0021] [ka]

[0022] Preferably, the steps include dissolving gabapentin in an aldehyde solution and adding a reducing agent to prepare a gabapentin derivative; More preferably, the aldehyde solution is an aqueous formaldehyde solution, and the amount of the aldehyde is 1-5 molar equivalents, preferably 3 molar equivalents; and / or the reducing agent is formic acid, and the amount of the reducing agent is 1-5 molar equivalents, preferably 4 molar equivalents; More preferably, the process according to the second aspect of the present invention, wherein the reaction temperature is from 60 to 90° C.; and / or the reaction time is from 3 to 12 hours.

[0023] A propofol derivative represented by formula (VIII) p The method includes the steps of:

[0024] [ka]

[0025] Preferably, the steps include dissolving Propofol in an organic solvent, adding a nucleophile, a base and an oxidizing agent to prepare a Propofol derivative; More preferably, the organic solvent is methanol, the nucleophile is sodium iodide, the base is sodium hydroxide, and / or the oxidizing agent is sodium hypochlorite; More preferably, the reaction temperature is 0° C. and / or the reaction time is 1 to 3 hours; Even more preferably, the process according to the second aspect of the invention, wherein the reaction is quenched after completion with sodium thiosulfate.

[0026] D g When coupling at the N-terminus of gabapentin, Boc-gabapentin is prepared first, followed by D p react with; Preferably, the method for preparing Boc-gabapentin includes the steps of stirring and suspending gabapentin in an organic solvent, sequentially adding and reacting NaHCO3 and Boc2O to obtain Boc-gabapentin; More preferably, the process according to the second aspect of the invention, wherein the organic solvent is preferably 1:1 tetrahydrofuran / water; NaHCO3 is used in an amount of 1-5 molar equivalents, preferably 3 molar equivalents; and / or Boc2O is used in an amount of 1-2 molar equivalents, preferably 1.1 molar equivalents.

[0027] further comprising the step of extracting the crude product with an organic solvent; Preferably, the process according to the second aspect of the invention, wherein the organic solvent is selected from one or more of dichloromethane, chloroform, diethyl ether, methanol, ethanol, isopropanol, benzene, and toluene; preferably dichloromethane.

[0028] A third aspect of the invention provides a pharmaceutical composition comprising: The pharmaceutical composition comprises the drug conjugate according to the first aspect or a pharma- ceutically acceptable salt thereof, or the drug conjugate or a pharma- ceutically acceptable salt thereof prepared by the preparation method according to the second aspect; Preferably, the dosage form of the pharmaceutical composition is selected from one or more of: a tablet, a capsule, an injection, a liposome, and a polymeric microsphere.

[0029] A fourth aspect of the present invention provides the use of a drug conjugate or a pharma- ceutically acceptable salt thereof according to the first aspect, or a drug conjugate or a pharma- ceutically acceptable salt thereof prepared by the preparation method according to the second aspect, in the preparation of a medicament for the treatment and / or prophylaxis of a central nervous system disease; Preferably, the central nervous system disorder is selected from one or more of convulsions, epilepsy, migraine, pain, and depression.

[0030] A fifth aspect of the present invention provides a method for treating a central nervous system disease, the method comprising administering to a subject in need thereof a drug conjugate according to the first aspect or a pharma- ceutical acceptable compound thereof or a pharmaceutical composition according to the third aspect; Preferably, the central nervous system disorder is selected from one or more of convulsions, epilepsy, migraine, pain, and depression.

[0031] A sixth aspect of the present invention provides a medicament for the treatment and / or prevention of a central nervous system disease, the medicament comprising a drug conjugate according to the first aspect or a pharma- ceutically acceptable salt thereof, or a drug conjugate or a pharma- ceutically acceptable salt thereof prepared by the preparation method according to the third aspect.

[0032] In order to find new effective new drug entities based on propofol, the present inventors formed a drug-drug conjugate by conjugating gabapentin or its derivatives with propofol. Up to now, the use of drug-drug conjugates has been mostly limited to anticancer drugs, and there have been no reports related to drug research in the central nervous system. In this invention, the present inventors couple gabapentin or its derivatives with propofol or its derivatives by a linker (or sometimes without a linker) to form a drug-drug conjugate and its crystalline form.

[0033] In a water solubility experiment of the synthetic drug conjugates, the present inventors found that the water solubility of each of the exemplary compounds 1, 2 and 5 was more than 10 mg / ml, indicating good water solubility.

[0034] In the lipophilicity experiment of the synthetic drug conjugates, the present inventors found that all of the exemplary compounds 1 to 6 have good lipophilic properties, and the lipid-water partition coefficients logP are 1.10, 1.66, 2.38, 3.52, 1.37, and 1.54. In general, regardless of whether the drug development of the central nervous system is successful or not, the compound needs to have good biological activity and metabolic properties and low toxicity to achieve sufficient exposure in the central nervous system, as well as good lipophilicity to overcome the blood-brain barrier (BBB). All of the drug conjugates of the present invention have good lipophilic properties, and such good lipophilic properties can effectively improve the permeability of such drugs through the blood-brain barrier, thereby improving the bioavailability of the drug.

[0035] In in vitro plasma degradation experiments, the inventors found that the conjugate of the present invention has good stability under neutral and acidic plasma conditions, indicating that the conjugate is likely to behave as a novel molecular entity that exerts pharmacodynamic effects in vivo, and that this type of conjugate may have more beneficial pharmacological properties than the inventors expected as a novel molecular entity. For example, a compound with improved plasma stability may have a longer drug action duration in vivo, an increased in vivo exposure, a reduced clearance rate, improved bioavailability, and improved pharmacokinetic and pharmacodynamic properties.

[0036] It has been found in the present invention that such drug conjugates have medicinal properties and can be used to treat and / or prevent central nervous system disorders such as convulsions / epilepsy, migraine headaches, pain and depression.

[0037] The present invention relates to drug conjugates in the form of drug-drug conjugate products, which are active in the treatment and / or prevention of, inter alia, convulsions / epilepsy, migraine headaches, depression.

[0038] The present invention also relates to methods for the synthesis of such molecules, which involve few synthetic steps and are therefore easy to carry out on an industrial scale.

[0039] The present invention also relates to the therapeutic use of such molecules, in particular in the treatment and / or prevention of convulsions / epilepsy, migraine headaches and depression.

[0040] The drug conjugates of the present invention are characterized in that they consist of coupling products according to formulas (I) and (II): D p -LD g (I) D p -LD g A (II) (In the formula, D g is gabapentin or a derivative thereof; D p is propofol and / or its derivatives; L is selected from a carbonyl group or may be absent; A represents a pharma- ceutically acceptable acidic anion, such as: sulfate, phosphate, hydrochloride, hydrobromide, acetate, oxalate, citrate, succinate, gluconate, tartrate, p-toluenesulfonate, benzenesulfonate, methanesulfonate, etc.

[0041] In preferred compounds of the present invention, D g represents gabapentin or its N-terminal partial derivatization product, linked as shown in formula III below:

[0042] [ka]

[0043] (wherein R1 is a methyl group or a hydrogen atom).

[0044] In preferred compounds of the present invention, D grepresents gabapentin or a derivative thereof represented by formula IV below.

[0045] [ka]

[0046] (wherein R2 and R3 may be the same or different and are a methyl group or a hydrogen atom).

[0047] In the present invention, preferably, D g is gabapentin or a derivative thereof represented by formula V below:

[0048] [ka]

[0049] (wherein R4, R5 and R6 may be the same or different and are a methyl group or a hydrogen atom, and A is as defined above).

[0050] In the present invention, preferably, D p is propofol or a derivative thereof of formula VI below:

[0051] [ka]

[0052] (wherein X is a halogen atom or a hydrogen atom).

[0053] The present invention also relates to methods for the preparation of related gabapentin and propofol derivatives.

[0054] a: Preparation of gabapentin derivatives represented by formula VII

[0055] [ka]

[0056] (wherein A, R2 and R3 are as defined above).

[0057] According to an embodiment of the present invention, the gabapentin derivative is prepared by dissolving gabapentin in an aldehyde solution (preferably an aqueous formaldehyde solution) and then adding a reducing agent (preferably formic acid). The reaction solution is preferably stirred at a temperature of 60°C to 90°C for 3 to 12 hours. The amount of aldehyde is preferably 3 molar equivalents, and the amount of reducing agent is preferably 4 molar equivalents. After cooling, the mixture is concentrated under reduced pressure and then mixed with an acid (preferably hydrochloric acid). The solution is stirred for 1 to 12 hours. The product is obtained by recrystallization.

[0058] b. Preparation of Propofol Derivatives Represented by Formula VIII

[0059] [ka]

[0060] (wherein X is as defined above).

[0061] According to an embodiment of the present invention, the propofol derivative is prepared by dissolving propofol in an organic solvent, preferably methanol. A nucleophile, preferably sodium iodide, and a base, preferably sodium hydroxide, are added. The amount of the nucleophile is preferably 1 molar equivalent, and the reaction is preferably carried out under stirring at 0°C. An oxidizing agent, preferably sodium hypochlorite, is added gradually at 0°C. The reaction is carried out for 1-3 hours and then quenched with sodium thiosulfate. The pH of the solution is adjusted to neutral with hydrochloric acid. The crude product is obtained by extraction with an organic solvent, e.g., diethyl ether; further purification by silica gel chromatography gives the product.

[0062] c: The coupling product of the gabapentin derivative of formula VII with propofol or a derivative of formula VIII is the conjugate of formula IX:

[0063] [ka]

[0064] (wherein X, A, R2, and R3 are as defined above).

[0065] According to an embodiment of the present invention, the coupling reaction is carried out by dissolving the gabapentin derivative represented by formula VII and propofol or a propofol derivative represented by formula VIII in an organic solvent (preferably dichloromethane). The amount of the acylating agent is preferably 2 molar equivalents. The mixture is reacted at low temperature, preferably at 0°C in a cooling bath, by stirring for 10-30 minutes. The acylating agent (preferably oxalyl chloride) is added together with an amide catalyst (preferably dimethylformaldehyde). The solution is stirred at 0-20°C for 5-16 hours to obtain the gabapentin derivative as an acid chloride.

[0066] The obtained crude product is redissolved in an organic solvent (preferably dichloromethane) in an ice bath, then an organic base (preferably pyridine) is added, followed by slow addition of Propofol or a Propofol derivative. The amount of organic base is preferably 2-3 equivalents. The mixture is stirred at 0-20°C for 5-12 hours, then washed with an aqueous hydrochloric acid solution, preferably an aqueous hydrochloric acid solution at pH 1. The crude product is obtained by extraction with dichloromethane, purified by silica gel chromatography, and finally recrystallized to the final product.

[0067] d: Gabapentin is coupled with propofol or a derivative thereof represented by formula VIII to prepare a conjugate represented by formula X.

[0068] [ka]

[0069] (wherein X and A1 are as defined above).

[0070] According to an embodiment of the present invention, the conjugate is prepared by suspending gabapentin and propofol or a propofol derivative represented by formula VIII in an organic solvent, preferably 1:1 tetrahydrofuran / water. The gabapentin suspension is stirred in an ice bath and a base (preferably sodium bicarbonate) is added, followed by an amine protecting agent (preferably di-tert-butyl dicarbonate). The amount of the amine protecting agent is preferably 1 molar equivalent. The reaction solution is heated to 20°C and stirred overnight. Extraction is performed with an organic solvent (preferably diethyl ether), and then the aqueous layer is acidified to pH 7 by careful addition of potassium bisulfate at 0°C. The resulting aqueous mixture is extracted with dichloromethane. The two organic phases are combined, dried over sodium sulfate, and the solvent is removed under reduced pressure. The white solid can be used in the next coupling reaction without further purification.

[0071] The white solid and propofol or its derivative obtained above are dissolved in an organic solvent (preferably dichloromethane), an amine catalyst (preferably 4-dimethylaminopyridine) is added, and a coupling agent (preferably N,N'-dicyclohexylcarbodiimide) dissolved in the same solvent is gradually added to the mixture at 0°C, and the mixture is stirred at 20°C for 5 to 18 hours. The reaction solution is filtered, and the solvent is removed under reduced pressure. The obtained crude coupling product is purified by silica gel chromatography.

[0072] The product obtained above is dissolved in an acidic solution, preferably diethyl ether in hydrogen chloride. The solution is stirred for 1-5 days, then the solvent is removed and the final product is obtained by recrystallization.

[0073] e. Gabapentin is coupled with propofol or a derivative of formula VIII to prepare XI.

[0074] [ka]

[0075] (wherein X and R1 are as defined above).

[0076] (1) According to an embodiment of the present invention, a conjugate of gabapentin and propofol or a propofol derivative represented by formula (VIII) is prepared by suspending gabapentin in an organic solvent (preferably dichloromethane). The gabapentin suspension is cooled to 0-15°C, an amine (preferably diisopropylethylamine) is added, and then an amine protecting agent (preferably chlorotrimethylsilane) is added. The solution is then stirred for 1-2 hours before proceeding to step (3).

[0077] (2) In a separate reaction vessel, propofol or a derivative thereof is dissolved in the same solvent as in the previous step at 0° C. Trichloromethyl carbonate (triphosgene) is added, preferably in an amount of 0.4 molar equivalents; then an amine, preferably diisopropylethylamine, is added. The reaction is stirred at 20° C. for 12-16 hours before proceeding to step (3).

[0078] (3) The reaction solution from step (2) was evaporated to near dryness under reduced pressure at 10-25° C., then redissolved in the same organic solvent as above, and the reaction solution from step (1) was slowly added dropwise thereto, followed by stirring for 12 hours at 25° C. The reaction solution was extracted with dichloromethane to obtain a crude product, which was further purified by column chromatography.

[0079] f: Preparation of the quaternary ammonium salt of the conjugate of formula XII from step e

[0080] [ka]

[0081] (wherein X, A, R2, R3 and R4 are as defined above).

[0082] According to an embodiment of the present invention, the free amine is extracted from the aqueous layer by dissolving the conjugate obtained from step C in water, adding sodium carbonate until the pH of the solution is 8, and extracting with an organic solvent (preferably dichloromethane). After removing the solvent under reduced pressure, methyl iodide is added as a solvent and reagent, stirred for 12 hours, and recrystallized to obtain the final product.

[0083] Migraine according to the present invention refers to the following condition: a pulsating headache on one or both sides of the head, with each attack lasting from several hours to several days, which usually causes nausea, vomiting and photophobia.

[0084] In the embodiment of the present invention, a nitroglycerin-induced migraine mouse model established by subcutaneous injection of nitroglycerin is selected, which is currently the most classic migraine model and has been widely used both at home and abroad in the experimentation and evaluation of drugs for treating migraine.

[0085] Behaviorally, scratching the head five times or scratching the face with the forepaws more than five times are considered as migraine-related behaviors induced by nitroglycerin; in the hot plate test, lifting of the hind paw and licking of the hind paw can be used as indicators to observe the analgesic effect.

[0086] The present invention evaluates the effect of the drug conjugate on nitroglycerin-induced migraine in mice, and uses the pain threshold of the hot plate test and head scratching behavior as observation indicators.The results show that the drug conjugate formed by gabapentin or its derivative and propofol or its derivative, or its pharma- ceutically acceptable salt, can effectively relieve the pain caused by nitroglycerin-induced migraine.

[0087] Longitudinal studies have shown that depression is a progressive, lifelong disorder that usually shows recurrences or long-lasting episodes (chronic depression). The mouse model of depression selected in the present embodiment is established by subcutaneous injection of lipopolysaccharide, which is widely used in the experimentation and evaluation of drugs to treat depression.

[0088] The effect of the test drug on spontaneous activity of mice was evaluated using an open field test apparatus and associated computer software to count the total distance traveled by each mouse in an open field (50×50×50 cm) for 5 min; a forced swimming test (FST) was used in which the mouse was placed in a transparent cylinder filled with warm water (about 25° C.) for 6 min. The mouse experienced behaviors such as struggling, forced swimming, and floating, and when the mouse stopped struggling and floated on the water surface, it was considered as a state of despair caused by depression.

[0089] The results of the tests of the examples of the present invention showed that a drug conjugate formed by gabapentin or a derivative thereof and propofol or a derivative thereof, or a pharma- ceutically acceptable salt thereof, can effectively alleviate depression in a mouse model induced by lipopolysaccharide.

[0090] The present invention evaluates the effect of this drug conjugate on mice with convulsions / epilepsy induced by electrical stimulation. The results show that the drug conjugate significantly improves the anti-electroconvulsive ability of mice at an effective dose, and is effective against convulsions / epilepsy.

[0091] The results of Test Examples 8 to 10 of the present invention demonstrated that a drug conjugate formed by gabapentin or a derivative thereof and propofol or a derivative thereof, or a pharma- ceutically acceptable salt thereof, has better sedative and antidepressant effects than the use of propofol alone or the combined use of gabapentin and propofol.

[0092] The drug conjugate and its pharma- ceutically acceptable salt prepared in the present invention can be in any dosage form, preferably in the form of a tablet, capsule, injection, lyophilized powder, emulsion, liposome or polymer microsphere. [Brief description of the drawings]

[0093] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. [Figure 1] FIG. 1 is a graph showing the comparative results of weight gain of individuals between groups in Test Example 1. [Diagram 2] FIG. 1 shows the results of a comparison of the time spent licking a hind paw between groups, measured by the hot plate method in Test Example 1. [Diagram 3] FIG. 1 shows a comparison of the total number of head scratching counts between groups in Test Example 1. [Figure 4] FIG. 1 shows the results of one-way ANOVA comparison of individual body weight gain between groups in Test Example 2. [Diagram 5] FIG. 13 shows the results of one-way ANOVA comparison of the total distance traveled in the open field between groups in Test Example 2. [Figure 6] FIG. 13 is a graph showing the results of one-way ANOVA comparison of FST immobility time between groups in Test Example 2. [Figure 7] FIG. 1 shows the results of one-way ANOVA comparison of mouse body weight gain in each group in Test Example 3. [Figure 8] FIG. 13 shows the results of one-way ANOVA comparing the increased threshold voltage values ​​measured before and after administration in each group of mice in Test Example 3. [Figure 9] FIG. 13 shows the results of one-way ANOVA comparing changes in preference for sugar water before and after administration in each group of mice in Test Example 9. [Figure 10] FIG. 13 shows the results of one-way ANOVA comparing changes in immobility time during forced swimming before and after administration in each mouse group in Test Example 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0094] The present invention will be further described below using specific examples; however, it should be understood that these examples are merely used for more detailed explanation and should not be construed as limiting the present invention in any way.

[0095] In this section, a general description of the materials and test methods used in the testing of the present invention is provided. Although many of the materials and procedures used for the purposes of the present invention are known in the art, the present invention is described in as much detail as possible. It is clear to those skilled in the art that the materials and procedures used in the present invention are well known in the art, even if not specifically mentioned in the context.

[0096] The reagents and equipment used in the following examples are as follows:

[0097] Reagents: Gabapentin was purchased from AK Scientific (CA, USA); THF, NaHCO3, Boc2O, diethyl ether, KHSO4, dichloromethane, Na2SO4, propofol, 4-dimethylaminopyridine, N,N'-dicyclohexylcarbodiimide, ethyl acetate, hexane, diethyl ether, methanol, sodium iodide, sodium hydroxide, sodium hypochlorite, sodium thiosulfate, hydrochloric acid, diisopropylethylamine, chlorotrimethylsilane, trichloromethane carbonate base ester, formic acid, formaldehyde, acetone, oxalyl chloride, dimethylformaldehyde, pyridine, CMC-Na aqueous solution, flunarizine hydrochloride, and nitroglycerin were purchased from Sigma-Aldrich.

[0098] Equipment and model: Nuclear magnetic resonance instrument, Bruker-400 mhz UltraShield NMR; High pressure liquid chromatography, Agilent-1100 series HPLC; Mass spectrometer, Waters ZMD 2000 MC365 mass spectrometer EXAMPLES

[0099] This example is used to illustrate the preparation of compound 1: 2,6-diisopropylphenyl 2-(1-(aminomethyl)cyclohexyl)acetate hydrochloride.

[0100] [ka]

[0101] Gabapentin (5.14 g, 30 mmol, 1 equiv) was suspended in THF / water (1:1, 180 ml) with stirring and cooled to 0° C. NaHCO3 (7.56 g, 90 mmol, 3 equiv) and Boc2O (7.6 mL, 33 mmol, 1.1 equiv) were added successively and the mixture was stirred at room temperature overnight. The reaction solution was extracted with diethyl ether (3×100 mL); the aqueous layer was acidified to pH 7 at 0° C. by careful addition of KHSO4 (10%); the aqueous phases were combined and extracted with dichloromethane (3×100 mL); the two organic phases were combined, dried over Na2SO4 and the solvent was removed under reduced pressure. Boc-gabapentin (7.4 g, 88%) was obtained as a white solid.

[0102] The Boc-gabapentin (5.7 g, 21 mmol, 1 equiv) and propofol (3.9 mL, 21 mmol, 1 equiv) obtained above were dissolved in dichloromethane (100 mL), and 4-dimethylaminopyridine (164 mg, 7% mol) was added. A mixed solution of N,N'-dicyclohexylcarbodiimide (4.3 g, 21 mmol, 1 equiv) dissolved in dichloromethane (20 mL) was slowly added to the above mixture at 0°C, and the mixture was stirred overnight at 20°C. The next day, the reaction solution was filtered to remove precipitates, and the filtrate was decompressed to remove the solvent, and the coupled product was purified by silica gel chromatography and eluted with 8% ethyl acetate in hexane (6.0 g, 66%).

[0103] The purified coupling compound obtained above (6.0 g, 13.9 mmol, 1 equiv) was dissolved in 2N hydrogen chloride in diethyl ether (70 ml, 10 equiv), the solution was stirred for 2 days, and then the solvent was removed to give a white solid (5.1 g, 100%). The final product was then recrystallized from diethyl ether.

[0104] 1 H NMR (chloroform-d1) δ:8.54(br.s.,3H), 7.13-7.25(m,3H), 3.15(br.s.,2H), 2.95( MS(m / z):C 21 H 34 Calculated value of ClNO2, 367.96; Found, [M-Cl] + , 331.87.

[0105] The solubility of compound 1 in water is 18 mg / ml; LogP: 1.10. EXAMPLES

[0106] This example is used to illustrate the preparation of compound 2: 4-iodo-2,6-diisopropylphenyl 2-(1-(aminomethyl)cyclohexyl)acetate hydrochloride.

[0107] [ka]

[0108] Propofol (3.43 mL, 18.5 mmol, 1 equiv) was dissolved in methanol (50 mL) and sodium iodide (2.77 g, 18.5 mmol, 1 equiv) and sodium hydroxide (0.74 g, 18.5 mmol, 1 equiv) were added. The reaction is preferably carried out under stirring at 0° C. Sodium hypochlorite (35 mL, 4%) was added slowly at 0° C. and the reaction was stirred for 1 hour and then quenched with sodium thiosulfate solution (20 mL, 10%). The pH of the reaction solution was adjusted to neutral with 5% hydrochloric acid and the crude product was obtained by extraction with diethyl ether. Purification was performed by silica gel chromatography and elution with 3% ethyl acetate in hexane. 4-Iodopropofol was obtained as a brown oil (2.4 g, 43%).

[0109] Gabapentin (5.14 g, 30 mmol, 1 equiv) was suspended in THF / water (1:1, 180 ml) with stirring and cooled to 0° C. NaHCO3 (7.56 g, 90 mmol, 3 equiv) and Boc2O (7.6 mL, 33 mmol, 1.1 equiv) were added successively and the mixture was stirred at room temperature overnight. The reaction solution was extracted with diethyl ether (3×100 mL); the aqueous phase was adjusted to pH 7 at 0° C. by careful addition of KHSO4 (10%); the aqueous phases were combined and extracted with dichloromethane (3×100 mL); the two organic phases were combined, dried over Na2SO4 and the solvent was removed under reduced pressure. Boc-gabapentin (7.4 g, 88%) was obtained as a white solid.

[0110] Boc-gabapentin (2.0 g, 7.5 mmol, 1 equiv) and 4-iodopropofol (2.3 mL, 7.5 mmol, 1 equiv) were dissolved in dichloromethane (20 mL) and 4-dimethylaminopyridine (60 mg, 7% mol) was added. To this mixture, a mixed solution of N,N'-dicyclohexylcarbodiimide (1.54 g, 7.5 mmol, 1 equiv) dissolved in dichloromethane (10 mL) was slowly added at 0°C and stirred overnight at 20°C. The next day, the reaction solution was filtered to remove precipitates, and the filtrate was depressurized to remove the solvent. The coupled product was purified and eluted by silica gel chromatography with 8% ethyl acetate in hexane (2.74 g, 66%).

[0111] The purified coupling compound obtained above (2.74 g, 5 mmol, 1 equiv.) was dissolved in 2N hydrogen chloride in diethyl ether (25 ml, 10 equiv.) and stirred for 2 days, then the solvent was removed to finally give a white solid (2.4 g, 100%).

[0112] 1 H NMR (chloroform-d1) δ:8.46(br.s.,3H), 7.44(s,2H), 3.13(br.s.,2H), 2.94(s,2 H), 2.76-2.88(m,2H), 1.45-1.68(m,10H), 1.16(d,J=7.0Hz,12H);MS(m / z):C 21 H 33 Calculated value of ClINO2, 493.85; Found, [M-Cl] + , 457.71.

[0113] The solubility of compound 2 in water is 13 mg / ml; LogP: 1.66. EXAMPLES

[0114] This example is used to illustrate a method for the preparation of compound 3: 2-(1-(((2,6-diisopropylphenoxy)carbonyl)methyl)cyclohexyl)acetic acid.

[0115] [ka]

[0116] Gabapentin (0.42 g, 2.45 mmol, 1 equiv) was suspended in dichloromethane (20 mL), cooled to 15° C., diisopropylethylamine was added, followed by chlorotrimethylsilane (0.62 mL, 4.9 mmol, 2 equiv), and the solution (Solution A) was stirred for 2 h. In a separate reaction vessel, propofol (0.48 mL, 2.56 mmol, 1.04 equiv) was dissolved in dichloromethane (10 mL) at 0° C., trichloromethyl carbonate (triphosgene) (0.37 g, 1.28 mmol, 0.5 equiv) was added, diisopropylethylamine (1.34 mL, 3.8 mmol, 3 equiv) was added, stirred at 20° C. for 12 h, evaporated to near dryness under reduced pressure at 25° C., and redissolved in dichloromethane (20 mL) (Solution B). Solution B was prepared by slowly adding solution A dropwise and stirring at 25° C. for 12 hours. The reaction mixture was extracted with dichloromethane to obtain a crude product, which was further purified by column chromatography eluting with 20% ethyl acetate in hexane. 2-(1-(((2,6-diisopropylphenoxy)carbonyl)methyl)cyclohexyl)acetic acid (0.64 g, 59%) was obtained as a white solid.

[0117] 1 H NMR (chloroform-d1) δ:7.13-7.18(m,3H), 5.61(t,J=6.7Hz,1H), 3.37(d,J=6.8Hz,2H), 2.97-3.1 (m,2H), 2.39(s,2H), 1.50-1.63(m,4H), 1.40-1.49(m,6H), 1.22(d,J=6.8Hz,12H);MS(m / z):C 22 H 33 Calculated NO4, 375.5; Found, [M+1] + ,375.94.

[0118] The solubility of compound 3 in water is 0.08 mg / ml; LogP: 2.38. EXAMPLES

[0119] This example is used to illustrate the preparation of compound 4: 2-(1-(((4-iodo-2,6-diisopropylphenoxy)carbonyl)methyl)cyclohexyl)acetic acid.

[0120] [ka]

[0121] Gabapentin (0.42 g, 2.45 mmol, 1 equiv) was suspended in dichloromethane (20 mL), cooled to below 15° C., diisopropylethylamine was added, followed by chlorotrimethylsilane (0.62 mL, 4.9 mmol, 2 equiv), and stirred for 2 h (Solution A). In a separate reaction vessel, 4-iodopropofol (0.48 mL, 2.56 mmol, 1.04 equiv) was dissolved in dichloromethane (10 mL) at 0° C., trichloromethylcarbonate (triphosgene) (0.37 g, 1.28 mmol, 0.5 equiv) was added, diisopropylethylamine (1.34 mL, 3.8 mmol, 3 equiv) was added, stirred at 20° C. for 12 h, and the reaction solution was evaporated to dryness under reduced pressure at 25° C., then redissolved in dichloromethane (20 mL) (Solution B). To the mixture B, solution A was slowly added dropwise and stirred at 25° C. for 12 hours. The reaction mixture was extracted with dichloromethane to obtain the crude product, which was further purified by column chromatography, eluting with 20% ethyl acetate in hexane. 2-(1-(((4-iodo-2,6-diisopropylphenoxy)carbonyl)methyl)cyclohexyl)acetic acid (0.88 g, 72%) was obtained as a white solid.

[0122] 1 H NMR (chloroform-d1) δ:7.43(s,2H), 5.64(t,J=6.7Hz,1H), 3.36(d,J=7.2Hz,2H), 2.89 -3.02(m,2H), 2.38(s,2H), 1.49-1.70(m,10H), 1.19(d,J=6.8Hz,12H);MS(m / z):C 22 H 32Calculated value of INO4, 501.4; Measured value, [M+1] + , 501.73.

[0123] The solubility of compound 4 in water is 0.04 mg / ml; LogP: 3.52. EXAMPLES

[0124] This example is used to illustrate the preparation of compound 5: 2,6-diisopropylphenyl 2-(1-((dimethylamino)methyl)cyclohexyl)acetate hydrochloride.

[0125] [ka]

[0126] Gabapentin (10 g, 58.34 mmol, 1 equiv) was dissolved in 37% aqueous formaldehyde solution (13 mL, 175.02 mmol, 3 equiv), 95% formic acid (9.44 mL, 233.36 mmol, 4 equiv) was added, and the reaction mixture was stirred and refluxed at 90° C. for 5 hours. After cooling to room temperature, the reaction solution was concentrated under reduced pressure, mixed with concentrated hydrochloric acid (37%) (6 mL), and stirred for 1 hour. Recrystallization in acetone and ether (4.1 g, 30%) gave N,N'-dimethylgabapentin.

[0127] N,N'-Dimethylgabapentin (1.9g, 8mmol, 1equiv) was dissolved in a mixed solvent of dichloromethane (15mL) and oxalyl chloride (1.7mL, 19.5mmol, 2.4equiv), and one drop of dimethylformaldehyde was added. The mixture was stirred in an ice bath for 30 minutes, and then stirred at 0-20°C for 5 hours to obtain the acid chloride product of N,N'-dimethylgabapentin.

[0128] The resulting pale yellow solid was redissolved in dichloromethane (15 mL) in an ice bath, pyridine (1.9 mL, 24.2 mmol, equiv) was slowly added, followed by propofol (1.1 mL, 6.45 mmol, 0.8 equiv) and stirred at 20° C. for 12 hours. The reaction solution was then washed with 1N aqueous HCl and extracted with dichloromethane to obtain the crude product. The crude product was subjected to silica gel chromatography and eluted with 5% methanol in dichloromethane. The final product was obtained by recrystallization in a mixed solvent of acetone and hexane (1.0 g, 39%).

[0129] 1 H NMR (chloroform-d1) δ: 11.50(s,1H), 7.08-7.13(m,3H), 3.46-3.58(m,2H), 3.30-3.41 (m,4H), 2.79-2.91(m,6H), 1.16-1.22(m,10H), 1.12(d,J=6.9Hz,12H);MS(m / z):C 23 H 38 Calculated value of ClNO2, 396.01; Found, [M-Cl] + , 359.84.

[0130] The solubility of compound 5 in water is 150 mg / ml; LogP: 1.37. EXAMPLES

[0131] This example is used to illustrate the preparation of compound 6: (1-(2-(2,6-diisopropylphenoxy)-2-oxoethyl)cyclohexyl)-N,N,N-tri-methylmethanaminium iodide.

[0132] [ka]

[0133] Compound 5: 2,6-diisopropylphenyl 2-(1-((dimethylamino)methyl)cyclohexyl)acetate hydrochloride (0.8 g, 2 mmol, 1 equiv.) prepared in Example 5 was dissolved in water, adjusted to pH 8 with aqueous sodium carbonate (10%, 40 mL), and the free amine was extracted from the aqueous layer with dichloromethane. After removing the solvent under reduced pressure, iodomethane (5 mL) was added and stirred for 12 hours. The final product was obtained by recrystallization with diethyl ether (0.9 g, 89%).

[0134] 1 H NMR (chloroform-d1) δ:7.16-7.14(m,3H), 3.87(s,2H), 3.59(br.s.,2H), 3.53(s,9H), 3.58(s ,4H), 3.10(s,2H), 2.69-2.80(m,2H), 1.17-1.20(m,10H), 1.10-1.15(m,12H);MS(m / z):C 24 H 40 Calculated value of INO2, 501.48; measured value, [MI] + , 373.97.

[0135] The solubility of compound 6 in water is 0.9 mg / ml; LogP: 1.54.

[0136] Test Example 1 This test example is used to illustrate the effect of Compound 5, prepared in Example 5, on a nitroglycerin-induced migraine mouse model.

[0137] Experimental animals and groups, sources 48 ICR mice, weighing 18-22g, half male and half female; purchased from Qinglongshan Animal Breeding Farm Co., Ltd., Jiangning District, Nanjing City, certificate: SCXK (Su) 2017-0001; rearing conditions: room temperature 18-20℃, same-sex cage rearing, 12-hour light and 12-hour ventilation, regular chow feeding at conventional regular rate, bedding changed every 2 days; 48 mice were randomly divided into 6 groups (blank control group, model group, positive drug group, low-dose test drug group, medium-dose test drug group, high-dose test drug group), with 8 mice (4♀4) in each group, marked with numbers 1-8 and picric acid, respectively.

[0138] Experimental Drugs and Preparations Solvent: 0.5% CMC-Na aqueous solution; Positive drug: Flunarizine hydrochloride (Siberium) capsule (standard 5mg) contents are taken into a mortar, crushed, and 100ml of 0.5% CMC-Na solution is added, and the capsule is placed in an EP tube for later use; Test drug (compound 5): Dissolve in distilled water to 5, 10, and 20mg / ml solutions, and the capsule is placed in an EP tube for later use; Model drug (nitroglycerin): Take two nitroglycerin tablets (standard 5mg), crush them into powder, place them in an EP tube, add 500μl of propylene glycol with a pipette, shake well, leave for 5 minutes, add 9.5ml of normal saline, shake well, leave overnight, and obtain the supernatant (containing 1mg / ml nitroglycerin) for use.

[0139] Modeling Methodology Except for the first group (blank control group), the individuals in other groups were subcutaneously injected with 10 mg / kg (0.2 ml / 20 g) nitroglycerin backup solution 1 hour after each administration (modeled once every other day on the 1st, 3rd, and 5th days).

[0140] Method of administration, dosage The first group is the blank control group, which is given 0.2ml / 20g of 0.5% CMC-Na by gavage; the second group is the model group, which is given 0.5% CMC-Na by gavage; the third group is the positive drug group, which is given 1mg / kg of flunarizine hydrochloride (Siberium) by gavage; the fourth group is the low dose group of the test drug, which is given 100mg / kg of compound 5 by gavage; the fifth group is the medium dose group of the test drug, which is given 200mg / kg of compound 5 by gavage; the sixth group is the high dose group of the test drug, which is given 400mg / kg of compound 5 by gavage. Administration is performed every other day on the 1st, 3rd, and 5th days.

[0141] Detection Method On the fifth day, the behavioral indexes of the mice were collected immediately after modeling, i.e., the number of scratches of each mouse was collected in three periods after modeling: 1-30 minutes, 30-60 minutes, and 60-90 minutes, and the first time the mouse exhibited head scratching behavior was recorded; 45 minutes after modeling, the time each mouse spent licking its hind paw was measured and recorded using a hot plate device.

[0142] Observation Indicators In the behavioral study, mice were observed to scratch their heads more than five times or to scratch their faces with their forelimbs more than five times as model-induced migraine-related behaviors, and one head scratch was recorded; in the hot plate study, mice were observed to lift their hind limbs or lick their hind paws, and the time was immediately recorded.

[0143] result As shown in Figures 1 to 3.

[0144] conclusion The data showed that the drug did not significantly affect the body weight of the mice. Statistically, there was no significant difference in body weight gain in all other groups compared to the blank group (p>0.05).

[0145] The results of pain threshold and head scratching behavior by hot plate test showed that the mouse nitroglycerin-induced migraine model was successful, and the test drug compound 5 can effectively alleviate nitroglycerin-induced migraine in mice. The statistical results showed that, compared with the model group, the blank group mice had a significant difference in the time spent licking their hind paws (p<0.05), and the total number of head scratches was significantly significant (p<0.01); the positive drug had a significant difference in the time spent licking between the medium and high dose groups of the test drug (p<0.05), and the positive drug had a significant difference in the total number of head scratches between the low and medium dose groups of the test drug (p<0.01), while the high dose group of the test drug had a significant difference (p<0.05).

[0146] Test Example 2 This test example is used to illustrate the effect of Compound 5 prepared in Example 5 on a lipopolysaccharide-induced depression mouse model.

[0147] Experimental animals and groups, sources The same as Test Example 1.

[0148] Clinical trial drugs and preparations Positive drug: Fluoxetine hydrochloride capsule (standard 20 mg) contents are placed in a mortar, ground, and 40 ml of 0.5% CMC-Na solution is added to make a suspension, and the EP tube is set for use; Test drug (compound 5): Dissolve in distilled water to make 5, 10, and 20 mg / ml solutions, and place in an EP tube for later use; Model drug (LPS): Take frozen lipopolysaccharide PBS solution (1.2 mg: 1.2 ml), thaw, and then use a pipette to take 1 ml into an EP tube, replace with a new pipette tip, pipette 9 ml of normal saline into the EP tube, shake well before use.

[0149] Modeling Methodology Mice in the other groups except for the first group (blank control group), the model group, the positive drug group, and the low, medium and high dose groups of the test drug were intraperitoneally injected with LPS 2 hours before the last administration on the 7th day.

[0150] Method of administration, dosage The first group was a blank control group, and was given 0.2ml / 20g of 0.5% CMC-Na by gavage; the second group was a model group, and was given 0.5% CMC-Na by gavage; the third group was a positive drug group, and was given 1mg / kg of flunarizine hydrochloride (siberium) by gavage; the fourth group was a low dose group of the test drug, and was given 100mg / kg of compound 5 by gavage; the fifth group was a medium dose group of the test drug, and was given 200mg / kg of compound 5 by gavage; the sixth group was a high dose group of the test drug, and was given 400mg / kg of compound 5 by gavage. The drugs were administered for one week, and the second to sixth groups were intraperitoneally injected with 1mg / kg (0.2ml / 20g) of LPS on the seventh day to establish the model.

[0151] Spontaneous Activity Detection Before the last administration and modeling on the 7th day, it is necessary to investigate the effect of the drug on the spontaneous activity of the mouse, to ensure that the drug increases the spontaneous activity of the mouse and does not interfere with the immobility time in the forced swimming experiment. The total movement distance of each mouse within 5 minutes in the open field (50 × 50 × 50 cm) was calculated using the open field experimental apparatus and related computer software. Before data collection, each mouse was given 5 minutes to get used to the open field environment, and after the test, each mouse was removed from the feces and the odor was removed with an alcohol spray bottle.

[0152] Forced swim test (FST) Four hours after intraperitoneal injection of LPS, behavioral indicators of mice were collected by a forced swimming test apparatus and associated computer software. The swimming state of each mouse in the cylinder was observed for 6 minutes, and the immobility time of the mouse within 4 minutes (i.e., 2 to 6 minutes) was recorded. Because of the low air temperature, it is appropriate to control the water temperature by adding hot water to the cylinder.

[0153] Observation Indicators In spontaneous activity, the behavior index was selected as the total distance traveled by the mouse in the open field within 5 min, the mouse was tracked by the monitoring device, and the total distance traveled could be directly obtained by using computer software; in the FST experiment, the mouse was placed in a transparent cylinder filled with warm water (about 25°C) for 6 min, the mouse experienced struggling, swimming and floating behavior, and the time when the mouse stopped struggling and floated to the surface of the water was considered as a state of despair caused by depression, and the total "immobility time" could be directly obtained by using the monitoring device and computer software to statistically analyze the state of the mouse after 4 min.

[0154] result As shown in Figures 4 to 6.

[0155] conclusion The results of the mouse body weight survey showed that the positive drug and test drug did not significantly affect the body weight of the mice, but the statistics based on the blank group showed that there was a significant difference in body weight gain between the positive drug group and the low-dose test drug group (p<0.01).

[0156] Regarding spontaneous activity, the positive and test drugs did not significantly affect the spontaneous activity of the mice. In the statistics, the blank group was used as the standard, and there was no significant difference in the total movement distance of the mice within 5 minutes in the other groups (p>0.05).

[0157] Depression Index-FST immobility time, the acute depression model was successfully reproduced by the LPS method, and the positive drug and test drug had a certain alleviating effect on the depressive behavior caused by LPS (no statistical difference was found); statistically, based on the model group, the immobility time of the blank group was significantly different (p<0.05), and the immobility time of the positive drug and test drug groups was not significantly different (p>0.05).

[0158] Test Example 3 This test example is used to illustrate the anticonvulsant effect of Compound 5 prepared in Example 5 on mice induced by electrical stimulation.

[0159] Sources of experimental animals The source is the same as in Test Example 1.

[0160] Screening and Classification of Animals (1) Forty mice (20♀20) were randomly divided into five groups with eight mice (4♀4) in each group, and labeled with picric acid as numbers 1 to 8, respectively; (2) All mice were tested for electrical stimulation in the order of group and labeling, with an initial voltage of 40 V, and the voltage was increased by 2.5 V each time, with a time interval of 20 min between two electrical stimuli for the same mouse, and the threshold voltage value of convulsions and the time to complete recovery from convulsions were recorded, and the mice that died were excluded to screen for eligible mice; (3) After screening, seven mice (2♀5) among the 40 mice could not recover after convulsions and died, leaving 33 eligible mice (18♀15); (4) From the mice that were set aside for later use, seven were screened as replacements, and the numbers of the mice that died in step (2) were marked with picric acid and added to the corresponding groups, finally obtaining a total of 40 eligible mice (20♀20) in five groups. All mice were weighed and recorded.

[0161] Experimental Drugs and Preparations Positive drug: sodium valproate (standard 0.2 g) was taken as one tablet in a mortar and crushed, while adding 20 ml of 0.5% CMC-Na solution to make a suspension, and the EP tube was set for use; test drug (compound 5): each was dissolved in distilled water to make 5, 10, and 20 mg / ml solutions, and the EP tube was set for later use.

[0162] Modeling Methodology Electrical stimulation was performed 1.5 hours after the last administration, and a pre-measured threshold voltage was applied to each mouse to observe experimental events, recording whether there were any convulsions and whether death occurred.

[0163] Method of administration, dosage The first group was the blank control group and was given 0.4ml / 20g of 0.5% CMC-Na by oral gavage; the second group was the positive drug control group and was given 200mg / kg of sodium valproate by oral gavage; the third group was the low dose group of the test drug and was given 100mg / kg of Compound 5 by oral gavage; the fourth group was the medium dose group of the test drug and was given 200mg / kg of Compound 5 by oral gavage; and the fifth group was the high dose group of the test drug and was given 400mg / kg of Compound 5 by oral gavage.

[0164] Observation Indicators 1.5 hours after the last administration, electrical stimulation is performed on each mouse according to the threshold voltage previously measured, experimental events are observed, and the occurrence of convulsion and death is recorded.If convulsion occurs, the complete recovery time is recorded; if convulsion does not occur, the voltage is continuously increased with a gradient of 2.5V, and the threshold voltage value and recovery time at that point are measured.

[0165] The five periods of convulsions in mice, namely, the latency period, flexion rigidity period, hindlimb extension period, clonic period and recovery period, are strictly followed to determine whether the mice had convulsions after electrical stimulation and whether they could not recover from convulsions and died after convulsions.

[0166] result As shown in Figures 7-8.

[0167] conclusion Compared with the blank group, there was no difference in the effect of the three dose groups of the positive drug and the test drug on the weight gain of the mice (p>0.05). Compared with the blank group, the positive drug group could significantly improve the anti-electroconvulsive ability of the mice (p<0.05); the test drug 100 and 200 mg / kg dose groups did not significantly affect the anti-electroconvulsive ability of the mice (p>0.05); the 400 mg / kg dose group could significantly improve the anti-electroconvulsive ability of the mice (p<0.01).

[0168] Test Example 4 In this test example, the hot plate method was used to investigate the analgesic effect of Compound 1 prepared in Example 1 on mice after intravenous administration.

[0169] Experimental animals and groups, sources Twenty ICR mice, 18-22 g, half male and half female, were purchased from the animal room of Xi'an Jiaotong University School of Medicine; rearing conditions were: room temperature 18-20°C, same-sex cages, 12-h light and 12-h light, regular ventilation, feeding with conventional solid food at regular rates, and bedding changed every 2 days; the 20 mice were randomly divided into two groups (low-dose test drug group and high-dose test drug group), with 10 mice (5♀5) in each group.

[0170] All mice included in the study were qualified through hot plate pain threshold testing prior to the study.

[0171] Device PL-200 Hot Sting Pain Meter (Chengdu Taimeng Technology Company)

[0172] Experimental Drugs and Preparations Compound 1 was accurately weighed and dissolved in 0.9% saline to a concentration of 5mg / ml (well dissolved and essentially transparent), which was used as the mother solution, which was diluted with normal saline to the appropriate concentration during the test according to the test requirements.

[0173] Method of administration, dosage The first group was the low dose test drug group, in which the test drug was administered at 10 mg / kg via tail vein injection; the second group was the high dose test drug group, in which the test drug was administered at 15 mg / kg via tail vein injection.

[0174] Experimental Method The mice were placed in a hot plate apparatus at a temperature of 55±0.5° C., and the pain thresholds of the mice were measured and recorded before administration, 30 minutes after administration, 60 minutes after administration, and 120 minutes after administration.

[0175] The results of the test are shown in Table 1 below.

[0176] [Table 1]

[0177] conclusion Compound 1 has good analgesic effect on mice in the hot plate test, with the most excellent analgesic effect at a dose of 10 mg / kg. Regarding the duration of action, good analgesic effect exists within 30 to 60 minutes after injection.

[0178] Test Example 5 In this test example, the analgesic effect of Compound 1 prepared in Example 1 on mice after intragastric administration was investigated using the hot plate method.

[0179] Experimental animals and groups, sources The same as Test Example 1.

[0180] All mice added to the experiment underwent hot plate pain threshold detection prior to the experiment to screen eligible mice with a pain threshold of 10 to 40 seconds.

[0181] Device Chengdu Taimeng Intelligent Hot Plate Instrument(Chengdu Taimeng Software)

[0182] Experimental Drugs and Preparations Compound 1 was accurately weighed and dissolved in distilled water to prepare a 100mg / ml mother solution, which was then diluted with double distilled water to 1.25mg / ml (25mg / kg) and 2.5mg / ml (50mg / kg); the positive control drug gabapentin was accurately weighed and dissolved in distilled water to prepare a 100mg / ml mother solution, which was then diluted with double distilled water to 10mg / ml (200mg / kg). All pharmaceuticals were prepared and used as needed.

[0183] Method of administration, dosage Only 40 eligible mice were divided into 4 groups, with half male and half female in each group. The first group was a blank group without any treatment; the second group was a positive control (gabapentin) 25mg / kg group; the third group was a test drug 25mg / kg group; and the fourth group was a test drug 50mg / kg group. All were administered orally by gavage.

[0184] Experimental Method The mice were placed in a hot plate apparatus with a temperature of 55±0.5° C., and the pain thresholds of the mice were measured and recorded before and 60 min after administration.

[0185] The results of the study are shown in Table 2 below.

[0186] [Table 2]

[0187] conclusion Compound 1 can prolong the reaction time of hot plate pain and has an analgesic effect equivalent to that of the positive drug gabapentin.

[0188] Test Example 6 This example is used to illustrate the stability of Compound 5, prepared in Example 5, in fresh and acidic rat plasma.

[0189] Experimental samples: Compound 5 prepared in Example 5; 5% glucose (Xi'an Jingxi Shuanghe Pharmaceutical Co., Ltd.); Rat plasma (Source: Animal Center, Department of Medicine, Xi'an Jiaotong University)

[0190] Preparation of fresh plasma samples: a: Compound 5 prepared in Example 5 was dissolved in purified water to prepare solution A at a concentration of 10 mg / ml; 150 μl of solution A was added to 660 μl of preheated plasma (37° C.) to obtain solution B; b: Solution B (5 μmol / ml) was stirred in a water bath at 37°C for a certain period (1 min, 2 min, 4 min, 8 min, 16 min, 30 min, 1 h, 2 h, 4 h), and 50 μl was sampled at each time point; c: 50 μl of sampled solution) was added to 950 μl of methanol (0.1% AcH) to precipitate plasma proteins to obtain mixture C; d: Mixture C was vortexed for 1 second, centrifuged at 12000r for 3 minutes, and the supernatant was collected for testing.

[0191] Preparation of acidified plasma samples: a: Compound 5 prepared in Example 5 was dissolved in purified water to prepare solution A at a concentration of 10 mg / ml; 150 μl of solution A was added to 660 μl of pre-warmed plasma (37° C.), and the pH was adjusted with 0.1% acetic acid to completely dissolve the sample to obtain solution B; b: Solution B (5 μmol / ml) was stirred in a water bath at 37°C for a certain period (1 min, 2 min, 4 min, 8 min, 16 min, 30 min, 1 h, 2 h, 4 h), and 50 μl was sampled at each time point; c: 50 μl of the sampled solution was added to 950 μl of methanol (0.1% AcH) to precipitate plasma proteins to obtain mixture C. d: Mixture C was vortexed for 1 second, centrifuged at 12000r for 3 minutes, and the supernatant was collected for testing.

[0192] Liquid phase detection: After the above centrifugation, 10 μl of the supernatant is collected and used as a measurement sample.

[0193] [Table 3]

[0194] [Table 4]

[0195] Conclusion: The detection results of the plasma samples showed that the test samples were not significantly degraded in fresh plasma and acidified plasma, indicating that the samples were relatively stable in fresh plasma and acidified plasma.

[0196] Test Example 7 In this test example, the hot plate method was used to investigate the analgesic effect of Compound 2 prepared in Example 2 on mice after intravenous administration.

[0197] Experimental animals and groups, sources Twenty ICR mice, 18-22 g, half male and half female, were purchased from the animal room of Xi'an Jiaotong University School of Medicine; rearing conditions were: room temperature 18-20°C, single-sex cage, 12-h light and 12-h ventilation, regular chow feeding, bedding changed every 2 days; the 20 mice were randomly divided into two groups (low-dose test drug group and high-dose test drug group), with 10 mice (5♀5) in each group.

[0198] All mice included in the study were qualified through hot plate pain threshold testing prior to the study.

[0199] Device PL-200 Hot Sting Pain Meter (Chengdu Taimeng Technology Company)

[0200] Experimental Drugs and Preparations Compound 2 was accurately weighed and dissolved in 5% glucose water to a concentration of 2mg / ml (well dissolved and essentially transparent), which was used as the mother solution, which was diluted with 5% glucose water to the appropriate concentration according to the test requirements during the test.

[0201] Method of administration, dosage The first group was the high dose test drug group, in which the test drug was administered at 10 mg / kg via tail vein injection; the second group was the low dose test drug group, in which the test drug was administered at 3 mg / kg via tail vein injection.

[0202] Experimental Method The mice were placed in a hot plate apparatus at a temperature of 55±0.5° C., and the pain thresholds of the mice were measured and recorded before administration, 30 minutes after administration, 60 minutes after administration, and 120 minutes after administration.

[0203] The results of the study are shown in Table 5 below.

[0204] [Table 5]

[0205] Conclusion: Compound 2 showed good analgesic effects in mice in the hot plate test, and was effective at 10 mg / kg 30 min after injection.

[0206] Test Example 8 This study investigated the sedative and hypnotic effects and related compatibility of Compound 5 using the mouse righting reflex test.

[0207] Experimental animals: SPF Kunming mice, male, 20-30g, Laboratory Animal Center of Lanzhou University (Certificate No.: SCXK (Gan) 2018-0002), housed in separate cages, temperature 22±1℃, humidity 50%, automatic light control 12h / 12h light / dark cycle (lights on 8:00h, lights off 20:00h, light intensity ≒100lux) environment, food and activity ad libitum, adapted to the experimental environment for 5 days.

[0208] Experimental drugs. Compound 5; Gabapentin (A); Propofol (abbreviated as Pro or P, 10mg / ml, dissolved in 10% DMSO); Diazepam (abbreviated as Dia) injection, specification: 2ml:10mg, Tianjin Jinyao Pharmaceutical Industrial Co., Ltd., batch number 1903111; Pro and Gabapentin (A) are mixed in dosage 1:1 (molar ratio) (dissolved in 10% DMSO). Classification and administration: 42 Kunming mice were selected and divided into 6 groups, with 7 mice in each group, as shown in Table 6 below, and all were administered by intraperitoneal injection.

[0209] [Table 6]

[0210] Righting reflex experiment method. Mice were weighed and intraperitoneally injected with drugs according to the corresponding doses, and the following items were recorded (if the righting reflex of an individual was not lost 20 minutes after drug injection, it was considered that the righting reflex was not lost): (1) The time from the start of administration to the loss of the righting reflex of the mouse (loss of righting reflex lasted more than 30 seconds) was taken as the latency of loss of righting reflex; (2) The time from the loss of righting reflex to the recovery of righting reflex (when three righting reflexes were completed within 1 minute, it was considered that the righting reflex was recovered) was recorded; (3) The activity of the individual was observed and recorded.

[0211] Statistical analysis. Experimental data were analyzed by SPSS 19.0 statistical software, and all data were expressed as mean ± SEM.

[0212] The experimental results are shown in Table 7 below. In the negative control group (saline and DMSO) and A1P1 group, the righting reflex of the mice was not lost, and there was no significant change in activity; in the diazepam group (Dia) and compound 5 group mice, the righting reflex was not lost, but the activity state was significantly reduced, and the gait was very unstable, and the effect of the drug was significant; in the propofol group (Pro group), the righting reflex of two mice was lost, and the activity of others was significantly reduced. The results show that compound 5 has a better sedative effect.

[0213] [Table 7]

[0214] Test Example 9 This study investigated the antidepressant effect and related compatibility of compound 5 using the mouse sugar preference test.

[0215] Experimental drugs: Clomipramine (CLI), Sigma, batch number: C7291, 10 mg / ml (10% DMSO); Reserpine (Res), Sigma, batch number: 83580, 1 mg / ml (10% DMSO);

[0216] Compound 5; gabapentin (A); propofol (abbreviated as Pro or P, 10 mg / ml in 10% DMSO); Pro and gabapentin were mixed at a dosage of 1:1 (10% in DMSO).

[0217] Laboratory animals, classification and administration SPF adult male Kunming mice, 20-30g, Laboratory Animal Center of Lanzhou University, Animal Certificate Number: SCXK (Gan) 2018-0002, housed in separate cages, temperature 22±1℃, humidity 50%, 12h / 12h light / dark cycle controlled by dynamic lighting (lights on 8:00h, lights off 20:00h, light intensity ≒100lux), individuals were allowed to eat and move freely. Male Kunming mice were selected, with 6-10 mice per group as shown in Table 8 below, and all were administered by intraperitoneal injection.

[0218] [Table 8]

[0219] Sugar water preference experiment method: Before the experiment, Kunming mice were selected and divided into several groups, and the individuals were trained to drink 2% sucrose water, and on the first day of the experiment, DMSO or Res was injected at 8:00, and DMSO, compound 5, Pro or CLI was injected at 9:00. (See Table 8 for details), then, one bottle of 2% sucrose water and one bottle of normal drinking water were placed, and the positions of sugar water and normal drinking water were exchanged every 12 hours; After the second intraperitoneal injection of DMSO, compound 5, Pro, A1P1 or CLI (see Table 8 for details), the individuals were fasted for 24 hours at 9:00 on the second day; At 9:00 on the third day, one bottle of 2% sucrose water and one bottle of normal drinking water were placed, and the individuals were weighed 2 hours later to calculate the amount of water they drank, and the amount of sucrose water and the amount of normal water were calculated by the formula: sugar water preference = sugar water drinking amount / total drinking amount, and used to evaluate the depressive behavior of the individuals.

[0220] Statistical analysis. Experimental data were analyzed by SPSS 19.0 statistical software, and all data were expressed as mean ± SEM.

[0221] Experimental results. The specific results are shown in Table 9 below (shown in Figure 9). Compared with the DMSO group, the mice in the Res+DMSO group had a significantly lower preference for sugar water. Based on the administration of the Res group, after intraperitoneal injection of CLI, the preference of the mice for sugar water increased significantly, indicating that the experimental process met the requirements of the test. Compared to the Res+DMSO group, the mice in other groups were administered various drugs after the injection of Res, among which, after the administration of Pro and compound 5, the preference of the mice for sugar and water increased significantly, there was a significant difference, and compound 5 had a significant antidepressant effect. After the administration of A1P1, there was no significant change in the preference for sugar water.

[0222] [Table 9]

[0223] Test Example 10 This study investigated the antidepressant effects and related compatibility of compound 5 using the forced swimming test in mice.

[0224] The experimental drugs, animals, classification and administration were the same as in the sugar water preference experiment.

[0225] Forced swimming test Preparation of depression animal model. Acute intraperitoneal injection of 6 mg / kg Res can induce a 1-week sustained reduction in monoamine neurotransmitters in the brain and depression-like behavior lasting 72 hours, and is often used to prepare depression models (Huang et al., 2004). The experimental procedure is as follows: on the first day of the experiment, Res (6 mg / kg) or 10% DMSO was injected intraperitoneally at 8:00, DMSO, Compound 5, A1P1, Pro or CLI was injected at 9:00, a second injection of DMSO, Compound 5, Pro or CLI was given at 9:00 a.m. on the second day, and the forced swim test was completed between 9:00 and 12:00 on the third day.

[0226] Forced swimming experiment process. The forced swimming experiment is an experiment in which animals are placed in a stressful environment from which they cannot escape, in order to detect the despair state of the animals' behavior (Porsolt et al., 1978). Male Kunming mice were selected and randomly divided into several groups. The experiment was conducted in a quiet, closed behavioral observation room with red light (25 lux) for room lighting. The experiment was divided into two stages. Stage 1: Adaptation experiment. From 9:00 to 12:00 h one day before the test, the individuals were placed in the forced swimming test device (plexiglass drum: diameter 20 cm, height 25 cm, water depth 12 cm, water temperature 21 to 25 °C, upper CCD camera connected to computer for recording), and after 15 minutes of adaptation, they were taken out, their fur was dried with a towel, and they were returned to their cages. Stage 2: Test experiment. The individuals of each group were placed in the forced swimming bucket for 5 minutes at the same time, and their behavioral activity during the test period was tracked, recorded by a digital camera, and then analyzed. Immobility time: the animal either does not move its limbs to keep its head above the water surface, or moves its hind limbs slightly and floats on the surface. The animal is assessed for depression-like behavior by detecting a state of despair based on immobility time.

[0227] Statistical analysis. The experimental data were analyzed by SPSS 19.0 statistical software, and all data were expressed as mean ± SEM. Data were analyzed by one-way ANOVA, and comparisons between two groups were performed using Fisher's least significant difference (LSD) test, and p<0.05 was considered statistically significant.

[0228] Experimental results. The specific results are shown in Table 10 below (shown in the attached Figure 10):

[0229] [Table 10]

[0230] Compared with the DMSO group, the immobility time of the mice in the Res+DMSO group during forced swimming was prolonged and had a significant difference, and based on the administration of the Res group, the immobility time of the mice in the depression model mice during forced swimming was significantly shortened after intraperitoneal injection of CLI. These results indicated that the experimental process met the test requirements.

[0231] Based on the administration of Res group, various drugs were intraperitoneally injected.Compared with Res+DMSO group, the forced immobility time of model mice after intraperitoneal injection of Pro or A1P1 was slightly shortened, and the forced immobility time of model mice after injection of compound 5 was slightly shortened;Compared with Res+Pro group, the forced immobility time of model mice was shortened, and there was a significant difference after intraperitoneal injection of Res+compound 5;Compared with Res+A1P1 group, in model mice after intraperitoneal injection of Res+compound 5, the forced immobility time of mice was shortened to some extent, but there was no significant difference.The results show that compound 5 has a significant antidepressant effect.

[0232] Although the present invention has been described to a certain degree of particularity, it will be apparent that suitable modifications may be made in various circumstances without departing from the spirit and scope of the invention. It is to be understood that the present invention is not limited to the described embodiments, but is encompassed by the following claims, including equivalents of each of the described elements.

Claims

1. A drug conjugate or a pharma- ceutically acceptable salt thereof, The structure of the drug conjugate is shown in formula (I): D ｐ -L-D ｇ (I) (In the formula, D ｇ is a derivative of gabapentin; L is selected from a carbonyl group or may be absent; D ｐ is selected from propofol or its derivatives The structure of the pharma- ceutically acceptable salt of the drug conjugate is shown in Formula (II): D ｐ -L-D ｇ (II) where A is a pharma- ceutically acceptable acidic anion. D g is a derivative of gabapentin represented by formula (III), formula (IV) or formula (V); 【Chemistry 1】 (wherein R 1 is a methyl group or a hydrogen atom, R 2 and R 3 are independently selected from a methyl group or a hydrogen atom, but are not simultaneously hydrogen atoms, and R 4 , R 5 and R 6 are independently selected from a methyl group or a hydrogen atom, but are not simultaneously hydrogen atoms). The drug conjugate or a pharma- ceutically acceptable salt thereof, wherein Dp is propofol or a derivative thereof as shown in formula (VI): 【Chemistry 2】 (wherein X is a halogen atom or a hydrogen atom)

2. A is selected from one or more of a sulfate ion, a phosphate ion, a hydrochloride ion, a hydrobromide ion, an acetate ion, an oxalate ion, a citrate ion, a succinate ion, a gluconate ion, a tartrate ion, a p-toluenesulfonate ion, a benzenesulfonate ion, and a mesylate ion. The drug conjugate of claim 1 or a pharma- ceutically acceptable salt thereof.

3. A method for preparing the drug conjugate or a pharma- ceutically acceptable salt thereof according to claim 1 or 2, comprising: The preparation method, comprising the step of preparing the drug conjugate by suspending Dp and Dg in an organic solvent.

4. The method of claim 3, comprising: The process according to the above, characterized in that the organic solvent is selected from one or more of dichloromethane, tetrahydrofuran / water, diethyl ether, methanol, ethanol, isopropanol, benzene, or toluene.

5. The method of claim 4, wherein the organic solvent is dichloromethane and / or tetrahydrofuran / water.

6. The preparation method comprises the step of: ｇ A process according to any one of claims 3 to 5, characterized in that it comprises the step of preparing 【Chemistry 3】 (wherein R 2 and R 3 are independently selected from a methyl group or a hydrogen atom, but are not simultaneously hydrogen atoms).

7. The method of claim 6, characterized in that the steps include dissolving gabapentin in an aldehyde solution and adding a reducing agent to prepare a gabapentin derivative.

8. The preparation method described in claim 7, characterized in that the aldehyde solution is an aqueous formaldehyde solution and the amount of the aldehyde is 1 to 5 molar equivalents, and / or the reducing agent is formic acid and the amount of the reducing agent is 1 to 5 molar equivalents.

9. The method of claim 8, wherein the amount of aldehyde is 3 molar equivalents and / or the amount of reducing agent is 4 molar equivalents.

10. The process according to claim 9, wherein the reaction temperature is 60-90° C. and / or the reaction time is 3-12 hours.

11. The preparation method comprises the step of: ｐ A process according to any one of claims 3 to 10, characterized in that it comprises the step of preparing 【Chemistry 4】 (wherein X is a halogen atom or a hydrogen atom)

12. The preparation method described in claim 11, characterized in that the steps include dissolving propofol in an organic solvent, and adding a nucleophilic reagent, a base and an oxidizing agent to prepare a propofol derivative.

13. The method of claim 12, wherein the organic solvent is methanol, the nucleophilic reagent is sodium iodide, the base is sodium hydroxide, and / or the oxidizing agent is sodium hypochlorite.

14. The process according to claim 13, characterized in that the reaction temperature is 0° C. and / or the reaction time is 1-3 hours.

15. The process according to claim 14, characterized in that the reaction is quenched with sodium thiosulfate after completion.

16. D ｇ is coupled to the N-terminus of the gabapentin derivative D g, the Boc-gabapentin derivative D g is first prepared, and then D ｐ The process according to any one of claims 3 to 5, characterized in that it comprises reacting 17. The method for preparing the Boc-gabapentin derivative Dg according to claim 16, characterized in that it comprises the steps of stirring and suspending the gabapentin derivative Dg in an organic solvent, and sequentially adding and reacting NaHCO3 and Boc2O to obtain the Boc-gabapentin derivative Dg.

18. The process according to claim 17, characterized in that the organic solvent is 1:1 tetrahydrofuran / water, NaHCO 3 is used in an amount of 1-5 molar equivalents, and / or Boc 2 O is used in an amount of 1-2 molar equivalents.

19. The process according to claim 18, characterized in that NaHCO 3 is used in an amount of 3 molar equivalents and / or Boc 2 O is used in an amount of 1.1 molar equivalents.

20. The process according to any one of claims 3 to 19, characterized in that it further comprises a step of extracting the crude product with an organic solvent.

21. The method of claim 20, wherein the organic solvent is selected from one or more of dichloromethane, chloroform, diethyl ether, methanol, ethanol, isopropanol, benzene, and toluene.

22. The method of claim 21, wherein the organic solvent is dichloromethane.

23. A pharmaceutical composition comprising the drug conjugate of claim 1 or 2 or a pharma- ceutically acceptable salt thereof.

24. The pharmaceutical composition of claim 23, wherein the dosage form of the pharmaceutical composition is selected from one or more of a tablet, a capsule, an injection, a liposome, and a polymeric microsphere.

25. 3. Use of the drug conjugate or a pharma- ceutically acceptable salt thereof according to claim 1 or 2 in the preparation of a medicament for the treatment and / or prevention of a central nervous system disease.

26. The use according to claim 25, characterized in that the central nervous system disease is selected from one or more of convulsions, epilepsy, migraine, pain, and depression.

27. A pharmaceutical for treating and / or preventing a central nervous system disease, comprising the drug conjugate according to claim 1 or 2 or a pharma- ceutically acceptable salt thereof.

28. The pharmaceutical composition described in claim 27, characterized in that the central nervous system disease is selected from one or more of convulsions, epilepsy, migraine, pain, and depression.

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