Preparation method of nafamostat mesylate

Abstract

The invention relates to the technical field of chemical pharmacy, and particularly discloses a preparation method of nafamostat mesylate. The preparation method comprises the following steps: adding 6-amidinyl-2-naphthol mesylate, 4-guanidinobenzoic acid hydrochloride and EDCI into a first solvent, and carrying out condensation reaction; adding a saturated sodium bicarbonate aqueous solution to obtain an intermediate; and adding the intermediate into a second solvent, adding methanesulfonic acid to form salt, and purifying to obtain the nafamostat mesylate. EDCI firstly reacts with a first solvent and is activated, nitrogen atoms with positive charges in EDCI after oxygen atoms on carbonyl carbon of carboxylic acid are activated are positively charged, the electrophilicity of carboxylic acid is increased, an active intermediate is formed, the active intermediate and alcohol are more easily subjected to nucleophilic substitution reaction, and dehydration condensation is performed to form an ester bond. EDCI is used as a condensing agent, so that the production efficiency and yield of the nafamostat mesylate are improved, the purity of the nafamostat mesylate is improved, the impurity content is reduced, the cost is low, and industrial production is easy.

Description

Technical Field

[0001] The invention relates to the technical field of chemical pharmacy, and in particular to a preparation method of nafamostat mesylate. Background Art

[0002] Nafamostat mesylate, chemical formula: C 21 H 25 N5O8S2, with the molecular structure shown in Formula I, is a synthetic serine protease inhibitor. It is used as an anticoagulant in hemodialysis and has a wide range of pharmacological activities. It is commonly used in clinical practice to treat diseases such as acute pancreatitis and disseminated intravascular coagulation.

[0003]

[0004] Formula I However, the existing preparation methods of nafamostat mesylate are not satisfactory in removing impurities. The presence of impurities not only affects the activity and stability of the drug, but also may cause adverse reactions and pose a potential threat to the health of patients. Some impurities may interact with the target compound, change the pharmacological properties of the drug, and lead to reduced or uncertain therapeutic effects. With the growing market demand for nafamostat mesylate, higher requirements are also placed on its production efficiency and quality to ensure its full efficacy and safety. In addition, the traditional preparation methods of nafamostat mesylate (including purification) generally rely on complex and expensive equipment and reagents, which increases production costs and operational difficulties, and limits the widespread application of drugs.

[0005] How to quickly and efficiently produce high-purity nafamostat mesylate, reduce the impurity content, and facilitate industrial production is a problem that needs to be solved at present. Summary of the invention

[0006] In view of the above problems, the present invention provides a preparation method of nafamostat mesylate, which uses 6-amidino-2-naphthol mesylate and p-guanidinobenzoic acid hydrochloride as reactants and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI) as a condensation agent, thereby improving the production efficiency and yield of nafamostat mesylate, and significantly improving the purity of nafamostat mesylate and reducing the impurity content.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: A method for preparing nafamostat mesylate comprises the following steps: S1, adding 6-amidino-2-naphthol methanesulfonate, p-guanidinobenzoic acid hydrochloride and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide to a first solvent for condensation reaction; then adding a saturated sodium bicarbonate aqueous solution to obtain an intermediate as shown in Formula 1; S2, adding the intermediate into a second solvent, and then adding methanesulfonic acid to form a salt, and purifying to obtain nafamostat mesylate;

[0008] Formula 1.

[0009] Compared with the prior art, the preparation method of nafamostat mesylate provided by the present invention uses 6-amidino-2-naphthol mesylate (its molecular structure is shown in formula II) and p-guanidinobenzoic acid hydrochloride (its molecular structure is shown in formula III) as reactants, and uses EDCI as a condensing agent. EDCI reacts with a reaction solvent (a first solvent) in a reaction system and is first activated. The activated EDCI reacts with a carboxylic acid. The nitrogen atom in EDCI is positively charged, and the oxygen atom on the carbonyl carbon of the carboxylic acid is partially positively charged. This positive charge increases the electrophilicity of the carboxylic acid, further forming an active intermediate, making it easier to react with subsequent alcohols; the active intermediate with electrophilicity is attacked by the alcohol, and the oxygen atom in the alcohol performs nucleophilic substitution on the carbonyl carbon of the active intermediate, and the carboxyl group of the carboxylic acid and the hydroxyl group of the alcohol undergo dehydration condensation to form an ester bond, and by-products (such as water-soluble urea generated by the reaction of EDCI and carboxylic acid) are generated at the same time; the by-products are easy to handle and can be effectively separated and removed by adding a saturated sodium bicarbonate aqueous solution.

[0010]

[0011] Formula II

[0012] Formula III.

[0013] Compared with DCC (dicyclohexylcarbodiimide) and DIC (diisopropylcarbodiimide), using EDCI as a condensation agent has the following advantages: (1) By-products are easy to handle: Dicyclohexyl urea produced by the DCC reaction has a certain solubility in general organic phases and is relatively difficult to handle; diisopropyl urea produced by DIC has relatively good solubility in organic solvents, but is still not as easy to handle as the water-soluble urea produced after the EDCI reaction.

[0014] (2) Avoiding the occurrence of certain side reactions: The use of EDCI can avoid the combination of amines and carboxyl groups, making the condensation reaction more selective, reducing the generation of by-products, and helping to improve the purity and yield of the target product.

[0015] (3) High catalytic efficiency: The stronger electrophilicity of EDCI molecules makes it easier for EDCI to react with carboxylic acids; EDCI can more effectively activate carboxylic acids in the reaction system, making it easier for them to react with p-guanidinobenzoic acid hydrochloride. This means that under the same reaction conditions, EDCI can promote the reaction faster and improve the efficiency and yield of the reaction.

[0016] (4) Cost saving: In the condensation esterification reaction involving DCC or DIC, a catalytic amount of DMAP (4-dimethylaminopyridine) is usually required to accelerate the reaction. DMAP is used as a nucleophilic acyl transfer reagent to react with O-acylisourea to generate an active amide ("active ester") intermediate, thereby reducing the occurrence of side reactions and accelerating the formation of esters. However, the use of EDCI does not require the addition of DMAP, which can improve the reaction efficiency and yield, and improve the purity of nafamostat mesylate.

[0017] The preparation method of nafamostat mesylate provided by the invention is simple to operate, low in cost, and easy to industrialize; it not only improves the production efficiency and yield of nafamostat mesylate, but also significantly improves the purity of nafamostat mesylate and reduces the impurity content.

[0018] Preferably, in S1, the preparation method of 6-amidino-2-naphthol methanesulfonate comprises the following steps: S1-1, hydrogen chloride is introduced into solvent a, and 6-cyano-2-naphthol is added to carry out alkalization reaction to obtain compound 1 as shown in formula 2; S1-2, adding solvent b and an aminating agent to the compound 1 to carry out an aminolysis reaction, cooling and crystallizing to obtain a compound 2 as shown in formula 3; S1-3, adding the compound 2 to the solvent c, and then adding methanesulfonic acid to form a salt, cooling and crystallizing to obtain the 6-amidino-2-naphthol methanesulfonate;

[0019] Formula 2

[0020] Formula 3.

[0021] The invention further improves the yield and purity of 6-amidino-2-naphthol methanesulfonate by limiting the preparation method of 6-amidino-2-naphthol methanesulfonate.

[0022] Further preferably, in S1-1, the solvent a is selected from methanol, ethanol or isopropanol.

[0023] Further preferably, in S1-1, the mass ratio of the 6-cyano-2-naphthol, the solvent a and the hydrogen chloride is 1:(1-20):(1-10), and further preferably 1:(10-20):(3-7).

[0024] Further preferably, in S1-1, the temperature of the alkalization reaction is 10°C to 50°C, and the reaction time is 10h to 25h. More preferably, in S1-1, the temperature of the alkalization reaction is 20°C to 30°C, and the reaction time is 11h to 15h.

[0025] Further preferably, in S1-2, the solvent b is selected from methanol or ethanol.

[0026] Further preferably, in S1-2, the aminating agent is aqueous ammonia.

[0027] More preferably, in S1-2, the mass ratio of the compound 1, the solvent b and the aminating agent is 1:(1-20):(1-10), and more preferably 1:(10-15):(3-7).

[0028] Further preferably, in S1-2, the temperature of the aminolysis reaction is 20°C to 80°C, and the reaction time is 2h to 10h. More preferably, in S1-2, the temperature of the aminolysis reaction is 50°C to 60°C, and the reaction time is 3h to 4h.

[0029] Further preferably, in S1-2, the temperature of the cooling crystallization is 0°C to 10°C, and the crystallization time is 1h to 2h.

[0030] Further preferably, in S1-3, the solvent c is selected from methanol or ethanol.

[0031] Further preferably, in S1-3, the mass ratio of the compound 2, the solvent c and the methanesulfonic acid is 1:(5~10):(0.01~1), and further preferably 1:(6~8):(0.4~0.8).

[0032] Further preferably, in S1-3, the salt-forming temperature is 10°C to 50°C, and the salt-forming time is 0.5h to 2h. More preferably, in S1-3, the salt-forming temperature is 20°C to 30°C, and the salt-forming time is 1.5h to 2h.

[0033] Further preferably, in S1-3, the temperature of the cooling crystallization is 0°C to 10°C, and the crystallization time is 1h to 3h.

[0034] Preferably, in S1, the preparation method of p-guanidinobenzoic acid hydrochloride comprises the following steps: S1-4, adding p-aminobenzoic acid to solvent d, adding cyanamide for addition reaction, adding aqueous hydrochloric acid solution, cooling and crystallizing to obtain the p-guanidinobenzoic acid hydrochloride.

[0035] The invention further improves the yield and purity of p-guanidinobenzoic acid hydrochloride by limiting the preparation method of p-guanidinobenzoic acid hydrochloride.

[0036] Further preferably, in S1-4, the solvent d is a 14 wt% to 17 wt% aqueous solution of hydrochloric acid; the mass concentration is more preferably 55% to 60%.

[0037] Further preferably, in S1-4, the mass ratio of the p-aminobenzoic acid, the solvent d and the cyanamide is 1:(1~10):(1~10), and further preferably 1:(1~5):(1~3).

[0038] Further preferably, in S1-4, the temperature of the addition reaction is 20°C to 80°C, and the reaction time is 2h to 12h. More preferably, in S1-4, the temperature of the addition reaction is 20°C to 30°C, and the reaction time is 2h to 4h.

[0039] Further preferably, in S1-4, the mass concentration of the aqueous hydrochloric acid solution is 1% to 10%, and further preferably 3% to 5%.

[0040] Further preferably, in S1-4, the mass ratio of the p-aminobenzoic acid to the aqueous hydrochloric acid solution is 1:(2.5~3.5).

[0041] Further preferably, in S1-4, the temperature of the cooling crystallization is 0°C to 10°C, and the crystallization time is 1h to 2h.

[0042] Preferably, in S1, the mass ratio of the 6-amidino-2-naphthol methanesulfonate, the p-guanidinobenzoic acid hydrochloride, the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and the first solvent is 1:(0.5~3):(0.5~5):(8~12), and more preferably 1:(0.7~1.5):(0.8~1.8):(9~11).

[0043] Preferably, in S1, the first solvent is dichloromethane.

[0044] The present invention selects dichloromethane as the first solvent, which can promote the condensation reaction, achieve a technical effect equivalent to or even better than that of pyridine, and overcome the defects of pyridine's high toxicity and high cost.

[0045] Preferably, in S1, the temperature of the condensation reaction is -30°C to 30°C, and the reaction time is 1h to 12h. Further preferably, in S1, the temperature of the condensation reaction is 5°C to 15°C, and the reaction time is 4h to 5h.

[0046] Preferably, in S1, the mass ratio of the 6-amidino-2-naphthol methanesulfonate to the saturated sodium bicarbonate aqueous solution is 1:(3-3.5).

[0047] The present invention further promotes the progress of the condensation reaction by limiting the conditions of the condensation reaction, thereby improving the purity and yield of the intermediate.

[0048] Preferably, in S2, the second solvent is selected from an acetone aqueous solution or a dichloromethane aqueous solution.

[0049] Further preferably, in S2, the mass ratio of acetone or dichloromethane to water in the second solvent is 1:(3.5~4.5).

[0050] Preferably, in S2, the mass ratio of the intermediate, the second solvent and the methanesulfonic acid is 1:(10-30):(1-10), and more preferably 1:(15-25):(3-5).

[0051] Preferably, in S2, the salt-forming temperature is 10°C to 50°C, and the salt-forming time is 0.5h to 10h. More preferably, in S2, the salt-forming temperature is 10°C to 15°C, and the salt-forming time is 1h to 2h.

[0052] Preferably, in S2, the purification comprises the following steps: The crude product of nafamostat mesylate obtained after the salt formation is added into the third solvent, activated carbon is added for decolorization, and the mixture is filtered; the obtained filtrate is cooled and crystallized to obtain nafamostat mesylate.

[0053] Further preferably, in S2, the third solvent is selected from at least two of water, acetone, methyl tert-butyl ether, tert-butyl acetate, methanol or ethanol.

[0054] Further preferably, in S2, the mass ratio of the crude nafamostat mesylate, the third solvent and the activated carbon is 1:(1~5):(0.01~1), more preferably 1:(3~3.5):(0.05~0.15).

[0055] Further preferably, in S2, the bleaching temperature is 40°C to 60°C, and the bleaching time is 30min to 60min.

[0056] Further preferably, in S2, the temperature of the cooling crystallization is 0°C to 20°C, and the crystallization time is 1 to 10 hours. More preferably, in S2, the temperature of the cooling crystallization is 0°C to 10°C, and the crystallization time is 1 to 2 hours.

[0057] The present invention adopts a specific method for purification, the purification method is simple, the labor cost and training cost are reduced, the purification efficiency is high, and the efficient purification of nafamostat mesylate can be achieved in a relatively short time, and the cost of each raw material is low, which is suitable for large-scale industrial production and has high market competitiveness. The specific third solvent can fully dissolve the target compound, lays a good foundation for the subsequent removal of impurities, and can also be recycled; a specific amount of activated carbon can accurately adsorb impurities, and the adsorption effect on the target compound is extremely small, thereby retaining the effective ingredients to the greatest extent and improving the yield of the nafamostat mesylate product. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is a high-resolution mass spectrum of nafamostat mesylate in Example 1 of the present invention; Figure 2 For the nafamostat mesylate in Example 1 of the present invention 1 HNMR spectrum; Figure 3 For the nafamostat mesylate in Example 1 of the present invention 13 CNMR spectrum; Figure 4 It is the HPLC spectrogram of nafamostat mesylate in Example 1 of the present invention; Figure 5 The HPLC spectrogram of nafamostat mesylate in Example 2 of the present invention; Figure 6 It is the HPLC spectrogram of nafamostat mesylate in Example 3 of the present invention; Figure 7 It is the HPLC spectrogram of nafamostat mesylate in Example 4 of the present invention; Figure 8 It is the HPLC spectrogram of nafamostat mesylate in Example 5 of the present invention; Fig. 9 It is the HPLC spectrogram of the crude product of nafamostat mesylate in Comparative Example 1 of the present invention; Fig.10 It is the HPLC spectrogram of the crude product of nafamostat mesylate in Comparative Example 2 of the present invention; Fig.11 It is the HPLC spectrum of the crude product of nafamostat mesylate in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0060] A method for preparing nafamostat mesylate (reaction equation is shown in formula IV), comprising the following steps: S1, prepare 6-amidino-2-naphthol methanesulfonate and p-guanidinobenzoic acid hydrochloride respectively: S1-1, hydrogen chloride is introduced into solvent a, and 6-cyano-2-naphthol is added to carry out alkalization reaction to obtain compound 1 as shown in formula 2; S1-2, adding solvent b and an aminating agent to the compound 1 to carry out an aminolysis reaction, cooling and crystallizing to obtain a compound 2 as shown in formula 3; S1-3, adding the compound 2 to the solvent c, and then adding methanesulfonic acid to form a salt, cooling and crystallizing to obtain the 6-amidino-2-naphthol methanesulfonate; S1-4, adding p-aminobenzoic acid to solvent d, adding cyanamide for addition reaction, adding aqueous hydrochloric acid solution, cooling and crystallizing to obtain the p-guanidinobenzoic acid hydrochloride; S2, adding the 6-amidino-2-naphthol methanesulfonate, the p-guanidinobenzoic acid hydrochloride and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide to the first solvent for condensation reaction; then adding a saturated sodium bicarbonate aqueous solution to obtain an intermediate as shown in Formula 1; S3, adding the intermediate into a second solvent, and then adding methanesulfonic acid to form a salt, to obtain a crude product of nafamostat mesylate; S4, adding the crude product of nafamostat mesylate into a third solvent, adding activated carbon for decolorization, filtering to remove the activated carbon; cooling the obtained filtrate for crystallization to obtain nafamostat mesylate.

[0061]

[0062] Formula IV.

[0063] It should be noted that there is no order of precedence between S1-1~S1-3 and S1-4.

[0064] Example 1 The present embodiment provides a method for preparing nafamostat mesylate, comprising the following steps: S1, prepare 6-amidino-2-naphthol methanesulfonate and p-guanidinobenzoic acid hydrochloride respectively: S1-1, 75.01 g of hydrogen chloride was introduced into 225.00 g of methanol, and after the introduction, 15.00 g (0.09 mol) of 6-cyano-2-naphthol was added, the mass ratio of 6-cyano-2-naphthol, methanol and hydrogen chloride was 1:15:5, mixed evenly, and alkalized at 25°C for 13 h. The mixture was filtered to obtain compound 1.

[0065] S1-2, add 13 times the mass of methanol and 5 times the mass of ammonia water to compound 1, mix well, carry out ammonolysis reaction at 50°C, and keep warm for 4 hours; after the reaction is completed, cool the temperature in an ice bath to 5°C, crystallize for 1 hour, and filter to obtain compound 2.

[0066] S1-3, compound 2 was added to 6.6 times the mass of methanol and 0.6 times the mass of methanesulfonic acid, mixed evenly, stirred at 20°C for 2 h to form a salt, cooled to 5°C, crystallized for 2 h, filtered, and 23.21 g (0.08 mol) of 6-amidino-2-naphthol methanesulfonate was obtained, with a yield of 92.73%.

[0067] S1-4, add 25.00g (0.18mol) of p-aminobenzoic acid to a hydrochloric acid aqueous solution (25.00g of purified water and 37.50g of concentrated hydrochloric acid), add 50.00g of cyanamide with stirring, the mass ratio of p-aminobenzoic acid, hydrochloric acid aqueous solution and cyanamide is 1:2.5:2, carry out addition reaction at 20°C, and keep warm for 4h; after the reaction is completed, add 75.00g of 4wt% dilute hydrochloric acid, mix well, reduce to 5°C, crystallize for 1h, filter with suction, and obtain 38.00g (0.18mol) of p-guanidinobenzoic acid hydrochloride, with a yield of 96.67%.

[0068] There is no order of precedence between S1-1~S1-3 and S1-4.

[0069] S2, take 20.00g (0.07mol) of 6-amidino-2-naphthol methanesulfonate, 30.00g (0.14mol) of p-guanidinobenzoic acid hydrochloride and 26.00g of EDCI and add them to 200.00g of dichloromethane, the mass ratio of 6-amidino-2-naphthol methanesulfonate, p-guanidinobenzoic acid hydrochloride, EDCI and dichloromethane is 1:1.5:1.3:10, mix well, carry out condensation reaction at 10°C, and keep warm for 5h; after the reaction is completed, add 65.08g of saturated sodium bicarbonate aqueous solution, filter with suction, and obtain 32.98g (0.07mol) of intermediate, with a yield of 98.75%.

[0070] S3, add the intermediate to the second solvent (527.68g purified water and 131.92g acetone), add 131.92g methanesulfonic acid dropwise at room temperature, the mass ratio of the intermediate, the second solvent and methanesulfonic acid is 1:20:4, stir at 10°C for 3h to form salt, filter, and vacuum dry at 50°C for 6h to obtain 34.88g (0.06mol) of crude nafamostat mesylate, with a yield of 92.40%, a purity of 99.449%, and a maximum single impurity of 0.135%.

[0071] S4, taking 10.0g of the crude product of nafamostat mesylate, adding it to 35.0g of the third solvent (a mixed solution of water, acetone and tert-butyl acetate in a mass ratio of 1:1:1), mixing evenly, adding 0.5g of activated carbon, the mass ratio of the crude product of nafamostat mesylate, the third solvent and the activated carbon is 1:3.5:0.05, stirring and decolorizing at 50°C for 45min, filtering to remove the activated carbon; cooling the obtained filtrate to 5°C for crystallization, filtering and collecting the crystals, and vacuum drying at 60°C for 4h to obtain 8.6g of nafamostat mesylate (its HPLC spectrum is shown in Figure 4 ), purity is 99.905%, and the maximum single impurity is 0.067%.

[0072] The structure of nafamostat mesylate was identified by nuclear magnetic resonance (NMR) analysis. Figures 1 to 3 As shown, its chemical structure is confirmed to be nafamostat mesylate. It should be noted that, Figure 1 In the mass spectrometry, no salt peak is observed.

[0073] Example 2 The present embodiment provides a method for preparing nafamostat mesylate, comprising the following steps: S1, prepare 6-amidino-2-naphthol methanesulfonate and p-guanidinobenzoic acid hydrochloride respectively: S1-1, 50.00 g of hydrogen chloride was introduced into 270.00 g of ethanol, and after the introduction, 15.00 g (0.09 mol) of 6-cyano-2-naphthol was added, the mass ratio of 6-cyano-2-naphthol, ethanol and hydrogen chloride was 1:18:3.3, mixed evenly, and alkalized at 30°C for 11 h. The mixture was filtered to obtain compound 1.

[0074] S1-2, add 10 times the mass of ethanol and 7 times the mass of ammonia water to compound 1, mix well, carry out ammonolysis reaction at 60°C, and keep warm for 3 hours; after the reaction is completed, cool the temperature in an ice bath to 0°C, crystallize for 1 hour, and filter to obtain compound 2.

[0075] S1-3, add 6 times the mass of methanol and 0.4 times the mass of methanesulfonic acid to compound 2, mix well, stir at 25 ° C for 1.5 h to form a salt, cool to 0 ° C, crystallize for 1 h, filter with suction, and obtain 22.89 g (0.08 mol) of 6-amidino-2-naphthol methanesulfonate, with a yield of 91.45%.

[0076] S1-4, add 25.00g (0.18mol) of p-aminobenzoic acid to a hydrochloric acid aqueous solution (50.00g of purified water and 75.00g of concentrated hydrochloric acid), add 75.00g of cyanamide with stirring, the mass ratio of p-aminobenzoic acid, hydrochloric acid aqueous solution and cyanamide is 1:5:3, carry out addition reaction at 30°C, and keep warm for 2h; after the reaction is completed, add 87.50g of 3wt% dilute hydrochloric acid, mix well, reduce to 0°C, crystallize for 1h, filter with suction, and obtain 38.81g (0.18mol) of p-guanidinobenzoic acid hydrochloride, with a yield of 98.73%.

[0077] There is no order of precedence between S1-1~S1-3 and S1-4.

[0078] S2, take 20.00g (0.07mol) of 6-amidino-2-naphthol methanesulfonate, 20.00g (0.09mol) of p-guanidinobenzoic acid hydrochloride and 16.00g of EDCI and add them to 180.00g of dichloromethane, the mass ratio of 6-amidino-2-naphthol methanesulfonate, p-guanidinobenzoic acid hydrochloride, EDCI and dichloromethane is 1:1:0.8:9, mix well, carry out condensation reaction at 15°C, and keep warm for 4h; after the reaction is completed, add 60.00g of saturated sodium bicarbonate aqueous solution, filter by suction, and obtain 30.57g (0.06mol) of intermediate, with a yield of 91.53%.

[0079] S3, add the intermediate to the second solvent (626.00g purified water and 139.00g acetone), add 152.85g methanesulfonic acid dropwise at room temperature, the mass ratio of the intermediate, the second solvent and methanesulfonic acid is 1:25:5, stir at 15°C for 2h to form salt, filter, and vacuum dry at 50°C for 6h to obtain 33.02g (0.06mol) of crude nafamostat mesylate, with a yield of 94.37%, a purity of 99.325%, and a maximum single impurity of 0.155%.

[0080] S4, taking 10.0g of the crude product of nafamostat mesylate, adding it to 32.5g of the third solvent (a mixed solution of water, methyl tert-butyl ether and tert-butyl acetate in a mass ratio of 1:1:1), mixing evenly, adding 1g of activated carbon, the mass ratio of the crude product of nafamostat mesylate, the third solvent and the activated carbon is 1:3.25:0.1, stirring and decolorizing at 60°C for 30min, filtering to remove the activated carbon; cooling the obtained filtrate to 10°C for crystallization, filtering and collecting the crystals, and vacuum drying at 60°C for 4h to obtain 8.3g of nafamostat mesylate (its HPLC spectrum is shown in Figure 5 ), purity is 99.851%, and the maximum single impurity is 0.081%.

[0081] The structure of nafamostat mesylate was identified by nuclear magnetic resonance (NMR) analysis technology, and its chemical structure was confirmed to be nafamostat mesylate.

[0082] Example 3 The present embodiment provides a method for preparing nafamostat mesylate, comprising the following steps: S1, prepare 6-amidino-2-naphthol methanesulfonate and p-guanidinobenzoic acid hydrochloride respectively: S1-1, 100.00 g of hydrogen chloride is passed into 180.00 g of isopropanol, and after the passing is completed, 15.00 g (0.09 mol) of 6-cyano-2-naphthol is added, the mass ratio of 6-cyano-2-naphthol, isopropanol and hydrogen chloride is 1:12:6.7, mixed evenly, and alkalized at 20°C for 15 h. The mixture is filtered to obtain compound 1.

[0083] S1-2, add 15 times the mass of methanol and 3 times the mass of ammonia water to compound 1, mix well, carry out ammonolysis reaction at 55°C, and keep warm for 4.5 hours; after the reaction is completed, cool the temperature in an ice bath to 10°C, crystallize for 1.5 hours, and filter to obtain compound 2.

[0084] S1-3, add 8 times the mass of methanol and 0.8 times the mass of methanesulfonic acid to compound 2, mix well, stir at 30°C for 1.5h to form salt, reduce the temperature to 10°C, crystallize for 2.5h, filter with suction, and obtain 23.02g (0.08mol) of 6-amidino-2-naphthol methanesulfonate, with a yield of 91.97%.

[0085] S1-4, add 25.00g (0.18mol) of p-aminobenzoic acid to a hydrochloric acid aqueous solution (16.30g of purified water and 21.20g of concentrated hydrochloric acid), add 37.50g of cyanamide with stirring, the mass ratio of p-aminobenzoic acid, hydrochloric acid aqueous solution and cyanamide is 1:1.5:1.5, carry out addition reaction at 25°C, and keep warm for 3h; after the reaction is completed, add 62.50g of 5wt% dilute hydrochloric acid, mix well, reduce to 10°C, crystallize for 2h, filter with suction, and obtain 38.20g (0.18mol) of p-guanidinobenzoic acid hydrochloride, with a yield of 97.18%.

[0086] There is no order of precedence between S1-1~S1-3 and S1-4.

[0087] S2, take 20.00g (0.07mol) of 6-amidino-2-naphthol methanesulfonate, 25.00g (0.12mol) of p-guanidinobenzoic acid hydrochloride and 36.00g of EDCI and add them to 220.00g of dichloromethane, the mass ratio of 6-amidino-2-naphthol methanesulfonate, p-guanidinobenzoic acid hydrochloride, EDCI and dichloromethane is 1:1.25:1.8:11, mix well, carry out condensation reaction at 5°C, and keep warm for 5h; after the reaction is completed, add 70.00g of saturated sodium bicarbonate aqueous solution, filter by suction, and obtain 33.01g (0.07mol) of intermediate, with a yield of 98.84%.

[0088] S3, add the intermediate to the second solvent (410.67g purified water and 117.33g dichloromethane), add 99.03g methanesulfonic acid dropwise at room temperature, the mass ratio of the intermediate, the second solvent and methanesulfonic acid is 1:16:3, stir at 10°C for 3h to form salt, filter, and vacuum dry at 50°C for 6h to obtain 34.87g (0.06mol) of crude nafamostat mesylate, with a yield of 92.29%, a purity of 98.743%, and a maximum single impurity of 0.255%.

[0089] S4, taking 10.0g of the crude product of nafamostat mesylate, adding it to 30.0g of the third solvent (a mixed solution of water, acetone and methyl tert-butyl ether in a mass ratio of 1:1:1), mixing evenly, adding 1.5g of activated carbon, the mass ratio of the crude product of nafamostat mesylate, the third solvent and the activated carbon is 1:3:0.15, stirring and decolorizing at 40°C for 55min, filtering to remove the activated carbon; cooling the obtained filtrate to 0°C for crystallization, filtering and collecting the crystals, and vacuum drying at 60°C for 4h to obtain 8.4g of nafamostat mesylate (its HPLC spectrum is shown in Figure 6 ), the purity is 99.802%, and the maximum single impurity is 0.093%.

[0090] The structure of nafamostat mesylate was identified by nuclear magnetic resonance (NMR) analysis technology, and its chemical structure was confirmed to be nafamostat mesylate.

[0091] Example 4 The present embodiment provides a method for preparing nafamostat mesylate, comprising the following steps: S1, prepare 6-amidino-2-naphthol methanesulfonate and p-guanidinobenzoic acid hydrochloride respectively: S1-1, 150.00 g of hydrogen chloride is passed into 300.00 g of methanol, and after the passing is completed, 15.00 g (0.09 mol) of 6-cyano-2-naphthol is added, the mass ratio of 6-cyano-2-naphthol, methanol and hydrogen chloride is 1:20:10, the mixture is mixed evenly, and an alkalization reaction is carried out at 50°C. The mixture is kept warm for 10 hours and filtered to obtain compound 1.

[0092] S1-2, add 20 times the mass of methanol and 10 times the mass of ammonia water to compound 1, mix well, carry out ammonolysis reaction at 80°C, and keep warm for 2h; after the reaction is completed, cool the temperature in an ice bath to 5°C, crystallize for 1h, and filter to obtain compound 2.

[0093] S1-3, add 9 times the mass of ethanol and 0.9 times the mass of methanesulfonic acid to compound 2, mix well, stir at 50°C for 0.5h to form salt, reduce the temperature to 5°C, crystallize for 2h, filter with suction, and obtain 23.22g (0.08mol) of 6-amidino-2-naphthol methanesulfonate, with a yield of 92.78%.

[0094] S1-4, add 25.00g (0.18mol) of p-aminobenzoic acid to a hydrochloric acid aqueous solution (83.33g of purified water and 116.67g of concentrated hydrochloric acid), add 175.00g of cyanamide with stirring, the mass ratio of p-aminobenzoic acid, hydrochloric acid aqueous solution and cyanamide is 1:8:7, carry out addition reaction at 80°C, and keep warm for 2h; after the reaction is completed, add 75.00g of 3wt% dilute hydrochloric acid, mix well, reduce to 5°C, crystallize for 1h, filter with suction, and obtain 38.28g (0.18mol) of p-guanidinobenzoic acid hydrochloride, with a yield of 97.39%.

[0095] There is no order of precedence between S1-1~S1-3 and S1-4.

[0096] S2, take 20.00g (0.17mol) of 6-amidino-2-naphthol methanesulfonate, 25.00g (0.12mol) of p-guanidinobenzoic acid hydrochloride and 80.00g of EDCI and add them to 240.00g of dichloromethane, the mass ratio of 6-amidino-2-naphthol methanesulfonate, p-guanidinobenzoic acid hydrochloride, EDCI and dichloromethane is 1:1.25:4:12, mix well, carry out condensation reaction at 30°C, and keep warm for 1.5h; after the reaction is completed, add 65.00g of saturated sodium bicarbonate aqueous solution, filter with suction, and obtain 31.85g (0.07mol) of intermediate, with a yield of 95.36%.

[0097] S3, add the intermediate to the second solvent (191.1g purified water and 764.4g acetone), add 254.80g methanesulfonic acid dropwise at room temperature, the mass ratio of the intermediate, the second solvent and methanesulfonic acid is 1:30:8, stir at 50°C for 40min to form salt, filter, and vacuum dry at 50°C for 6h to obtain 33.58g (0.06mol) of crude nafamostat mesylate, with a yield of 92.13%, a purity of 98.12%, and a maximum single impurity of 0.395%.

[0098] S4, taking 10.0g of the crude product of nafamostat mesylate, adding it to 40.0g of the third solvent (a mixed solution of water, acetone and methanol in a mass ratio of 1:1:1), mixing evenly, adding 0.3g of activated carbon, the mass ratio of the crude product of nafamostat mesylate, the third solvent and the activated carbon is 1:4:0.3, stirring and decolorizing at 50°C for 30min, filtering to remove the activated carbon; cooling the obtained filtrate to 15°C for crystallization, filtering and collecting the crystals, and vacuum drying at 60°C for 4h to obtain 8.0g of nafamostat mesylate (its HPLC spectrum is shown in Figure 7 ), purity is 99.778%, and the maximum single impurity is 0.076%.

[0099] The structure of nafamostat mesylate was identified by nuclear magnetic resonance (NMR) analysis technology, and its chemical structure was confirmed to be nafamostat mesylate.

[0100] Example 5 The present embodiment provides a method for preparing nafamostat mesylate, comprising the following steps: S1, prepare 6-amidino-2-naphthol methanesulfonate and p-guanidinobenzoic acid hydrochloride respectively: S1-1, 15.00 g of hydrogen chloride is passed into 15.00 g of methanol, and after the passing is completed, 15.00 g (0.09 mol) of 6-cyano-2-naphthol is added, the mass ratio of 6-cyano-2-naphthol, methanol and hydrogen chloride is 1:1:1, and the mixture is mixed evenly. Alkalinization reaction is carried out at 10°C, and the mixture is kept warm for 20 h. The mixture is filtered to obtain compound 1.

[0101] S1-2, add 5 times the mass of methanol and 2 times the mass of ammonia water to compound 1, mix well, carry out ammonolysis reaction at 20°C, and keep warm for 8 hours; after the reaction is completed, cool the temperature in an ice bath to 5°C, crystallize for 1 hour, and filter to obtain compound 2.

[0102] S1-3, add 5 times the mass of methanol and 0.1 times the mass of methanesulfonic acid to compound 2, mix well, stir at 10°C for 2 h to form a salt, reduce the temperature to 5°C, crystallize for 2 h, filter with suction, and obtain 22.53 g (0.08 mol) of 6-amidino-2-naphthol methanesulfonate, with a yield of 90.01%.

[0103] S1-4, add 25.00 g (0.18 mol) of p-aminobenzoic acid to a hydrochloric acid aqueous solution (10.00 g of purified water and 15.00 g of concentrated hydrochloric acid), add 25.00 g of cyanamide with stirring, the mass ratio of p-aminobenzoic acid, hydrochloric acid aqueous solution and cyanamide is 1:1:1, carry out addition reaction at 20°C, and keep warm for 10 hours; after the reaction is completed, add 75.00 g of 3 wt% dilute hydrochloric acid, mix well, reduce to 5°C, crystallize for 1 hour, filter with suction, and obtain 35.87 g (0.17 mol) of p-guanidinobenzoic acid hydrochloride, with a yield of 91.25%.

[0104] There is no order of precedence between S1-1~S1-3 and S1-4.

[0105] S2, take 20.00g (0.07mol) of 6-amidino-2-naphthol methanesulfonate, 15.00g (0.07mol) of p-guanidinobenzoic acid hydrochloride and 12.00g of EDCI and add them to 160.00g of dichloromethane, the mass ratio of 6-amidino-2-naphthol methanesulfonate, p-guanidinobenzoic acid hydrochloride, EDCI and dichloromethane is 1:0.75:0.6:8, mix well, carry out condensation reaction at -18°C, and keep warm for 10h; after the reaction is completed, add 65.00g of saturated sodium bicarbonate aqueous solution, filter by suction, and obtain 29.97g (0.06mol) of intermediate, with a yield of 89.74%.

[0106] S3, add the intermediate to the second solvent (60.00g purified water and 24.00g acetone), add 45.00g methanesulfonic acid dropwise at room temperature, the mass ratio of the intermediate, the second solvent and methanesulfonic acid is 1:10:1.5, stir at 10°C for 7h to form salt, filter, and vacuum dry at 50°C for 6h to obtain 30.59g (0.06mol) of crude nafamostat mesylate, with a yield of 89.16%, a purity of 97.437%, and a maximum single impurity of 0.324%.

[0107] S4, taking 10.0g of the crude product of nafamostat mesylate, adding it to 20.0g of the third solvent (a mixed solution of water and acetone in a mass ratio of 1:1), mixing evenly, adding 5.0g of activated carbon, the mass ratio of the crude product of nafamostat mesylate, the third solvent and the activated carbon being 1:2:0.5, stirring and decolorizing at 50°C for 30min, filtering to remove the activated carbon; cooling the obtained filtrate to 18°C ​​for crystallization, filtering and collecting the crystals, and vacuum drying at 60°C for 4h to obtain 8.1g of nafamostat mesylate (its HPLC spectrum is shown in Figure 8 ), the purity is 99.707%, and the maximum single impurity is 0.086%.

[0108] The structure of nafamostat mesylate was identified by nuclear magnetic resonance (NMR) analysis technology, and its chemical structure was confirmed to be nafamostat mesylate.

[0109] Comparative Example 1 This comparative example provides a method for preparing a crude product of nafamostat mesylate, comprising the following steps: S1, take 20.00g (0.07mol) of 6-amidino-2-naphthol methanesulfonate prepared according to steps S1-1 to S1-3 of Example 1, 32.50g (0.15mol) of p-guanidinobenzoic acid hydrochloride prepared according to step S1-4 of Example 1, add them to 160.00g of pyridine, then add 11.83g of DCC and 0.33g of DMAP, mix well, carry out condensation reaction at room temperature, and keep warm for 12h; after the reaction is completed, filter, add 40g of pyridine to the filter cake for washing, add 65.00g of saturated sodium bicarbonate aqueous solution to the filtered filtrate, filter with suction to obtain a filter cake, and combine with the washed filter cake to obtain 22.10g (0.05mol) of the intermediate, with a yield of 66.17%.

[0110] S2, the intermediate is added to the second solvent (353.60g purified water and 88.40g acetone), 88.40g methanesulfonic acid is added dropwise at room temperature, the mass ratio of the intermediate, the second solvent and methanesulfonic acid is 1:20:4, after the addition, the mixture is stirred at 10°C for 3h to form a salt, filtered, and dried under vacuum at 50°C for 6h to obtain 23.00g (0.04mol) of crude nafamostat mesylate (its HPLC spectrum is shown in Fig. 9 ), the yield was 90.93%, the purity was 86.84%, and the maximum single impurity was 3.47%.

[0111] Comparative Example 2 This comparative example provides a method for preparing a crude product of nafamostat mesylate, comprising the following steps: S1, add 34.00g (0.20mol) of 6-cyano-2-naphthol and 300mL of anhydrous ethanol to a 1000mL three-necked flask, introduce dry hydrogen chloride gas to saturation under ice bath conditions, react with stirring at 25°C for 24h, evaporate until the reaction liquid remains about 150mL, add 150mL of anhydrous ethanol, raise the temperature to 50°C, introduce dry ammonia for 3h, and evaporate by rotary evaporation; after the rotary evaporation, add 400mL of saturated sodium bicarbonate solution, precipitate solid, filter with suction, wash the filter cake with water, and vacuum dry at 50°C for 6h; add Add 100 mL of methanol, add 21.25 g of methanesulfonic acid dropwise under ice bath condition, stir at room temperature for 0.5 h to form salt; add 100 mL of ether, precipitate solid, filter with suction, wash the filter cake twice with 30 mL of ether, add 300 mL of anhydrous ethanol, heat and reflux at 80 ° C, after the solid is completely dissolved, add activated carbon for decolorization, filter while hot; cool to 5 ° C for crystallization, filter with suction, and dry in vacuo at 50 ° C for 6 h to obtain 46.52 g (0.16 mol) of light yellow crystals of 6-amidino-2-naphthol methanesulfonate, with a yield of 81.99%.

[0112] S2, add 28.23g (0.10mol) of 6-amidino-2-naphthol methanesulfonate and 21.56g of p-guanidinobenzoic acid hydrochloride prepared according to step S1-4 of Example 1 into a 500mL three-necked flask, add 250mL of anhydrous pyridine, 24.76g of DCC and 24.43g of DMAP, and stir at 25°C for 5h; after the reaction, filter with suction, wash the filter cake twice with 30mL of pyridine, and obtain 31.08g (0.06mol) of crude nafamostat mesylate (its HPLC spectrum is shown in Fig.10 ), the yield was 57.60%, the purity was 81.28%, and the maximum single impurity was 6.16%.

[0113] Comparative Example 3 This comparative example provides a method for preparing a crude product of nafamostat mesylate, comprising the following steps: S1, 20.00 g (0.12 mol) of 6-cyano-2-naphthol was placed in a 250 mL three-necked flask, 120 mL of 30 wt% hydrochloric acid ethanol solution was added, and the mixture was stirred at 25 °C for 12 h. After the reaction was completed, the mixture was rotary evaporated to obtain a yellow solid; Add 200 mL of methanol to the yellow solid, pass ammonia gas until the yellow color completely disappears, and then evaporate to obtain 6-amidino-2-naphthol; Add 100 mL of methanol to 6-amidino-2-naphthol, cool to 0°C, and add methanesulfonic acid dropwise under temperature control. The addition is completed within 2 h. Stir for 1 h after the addition. The solution changes from turbid to clear. Add 100 mL of isopropyl ether and stir for 0.5 h. Filter with suction to obtain 27.49 g (0.10 mol) of light yellow 6-amidino-2-naphthol methanesulfonate, with a yield of 82.37%.

[0114] S2, add 10.00 g (0.05 mol) of p-guanidinobenzoic acid hydrochloride prepared according to step S1-4 of Example 1 to a 250 mL three-necked flask, add 100 mL of pyridine, stir until dissolved, then add 5.30 g of DIC, stir for 1 h, add 0.057 g of DMAP and 13.09 g (0.05 mol) of 6-amidino-2-naphthol methanesulfonate, stir at 25° C. for 12 h, after the reaction is complete, filter and obtain a white solid; add 50 mL of methanol and 10 mL of ethyl acetate to the white solid, beat for 1 h, filter and obtain 9.52 g (0.25 mol) of crude nafamostat, with a yield of 59.10%.

[0115] S3, add 32 mL of methanol and 8 mL of water to a 100 mL three-necked flask, heat to 50°C, add 8.00 g (0.02 mol) of crude nafamostat, stir until dissolved, drop 5.6 g of methanesulfonic acid, add 0.4 g of activated carbon after the drop, stir for 20 min, filter while hot, crystallize the filtrate at 0°C for 6 h, filter with suction, and obtain 10.31 g (0.02 mol) of crude nafamostat mesylate (its HPLC spectrum is shown in Fig.11 ), the yield was 82.97%, the purity was 84.83%, and the maximum single impurity was 4.45%.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing nafamostat mesylate, characterized in that, The following steps are involved: S1, adding 6-amidino-2-naphthol methanesulfonate, p-guanidinobenzoic acid hydrochloride and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide to a first solvent for condensation reaction; then adding a saturated sodium bicarbonate aqueous solution to obtain an intermediate as shown in Formula 1; S2, adding the intermediate into a second solvent, and then adding methanesulfonic acid to form a salt, and purifying to obtain nafamostat mesylate; Formula 1.

2. The method for preparing nafamostat mesylate as claimed in claim 1, wherein In S1, the mass ratio of the 6-amidino-2-naphthol methanesulfonate, the p-guanidinobenzoic acid hydrochloride, the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and the first solvent is 1:(0.5-3):(0.5-5):(8-12); In S1, the first solvent is dichloromethane.

3. The preparation method of nafamostat mesylate as claimed in claim 1, characterized in that, In S1, the temperature of the condensation reaction is -30°C to 30°C, and the reaction time is 1h to 12h.

4. The method for preparing nafamostat mesylate as claimed in claim 1, wherein In S2, the second solvent is selected from an acetone aqueous solution or a dichloromethane aqueous solution, and the mass ratio of acetone or dichloromethane to water is 1:(3.5-4.5); In S2, the mass ratio of the intermediate, the second solvent and the methanesulfonic acid is 1:(10-30):(1-10); In S2, the salt-forming temperature is 10°C to 50°C, and the salt-forming time is 0.5h to 10h.

5. The method for preparing nafamostat mesylate as claimed in claim 1, wherein In S2, the purification comprises the following steps: The crude product of nafamostat mesylate obtained after the salt formation is added into the third solvent, activated carbon is added for decolorization, and the mixture is filtered; the obtained filtrate is cooled and crystallized to obtain nafamostat mesylate.

6. The method for preparing nafamostat mesylate as claimed in claim 5, wherein In S2, the third solvent is selected from at least two of water, acetone, methyl tert-butyl ether, tert-butyl acetate, methanol or ethanol; In S2, the mass ratio of the crude nafamostat mesylate, the third solvent and the activated carbon is 1:(1-5):(0.01-1).

7. The method for preparing nafamostat mesylate according to claim 1, wherein In S1, the preparation method of 6-amidino-2-naphthol methanesulfonate comprises the following steps: S1-1, hydrogen chloride is introduced into solvent a, and 6-cyano-2-naphthol is added to carry out alkalization reaction to obtain compound 1 as shown in formula 2; S1-2, adding solvent b and an aminating agent to the compound 1 to carry out an aminolysis reaction, cooling and crystallizing to obtain a compound 2 as shown in formula 3; S1-3, adding the compound 2 to the solvent c, and then adding methanesulfonic acid to form a salt, cooling and crystallizing to obtain the 6-amidino-2-naphthol methanesulfonate; Formula 2 Formula 3.

8. The method for preparing nafamostat mesylate as claimed in claim 7, wherein In S1-1, the solvent a is selected from methanol, ethanol or isopropanol; In S1-1, the mass ratio of the 6-cyano-2-naphthol, the solvent a and the hydrogen chloride is 1:(1-20):(1-10); In S1-1, the alkalization reaction temperature is 10°C to 50°C, and the reaction time is 10h to 25h; In S1-2, the solvent b is selected from methanol or ethanol; In S1-2, the aminating agent is aqueous ammonia; In S1-2, the mass ratio of the compound 1, the solvent b and the aminating agent is 1:(1-20):(1-10); In S1-2, the temperature of the ammonolysis reaction is 20°C to 80°C, and the reaction time is 2h to 10h; In S1-3, the solvent c is selected from methanol or ethanol; In S1-3, the mass ratio of the compound 2, the solvent c and the methanesulfonic acid is 1:(5-10):(0.01-1); In S1-3, the salt-forming temperature is 10°C to 50°C, and the salt-forming time is 0.5h to 2h.

9. The method for preparing nafamostat mesylate according to claim 1, wherein In S1, the preparation method of p-guanidinobenzoic acid hydrochloride comprises the following steps: S1-4, adding p-aminobenzoic acid to solvent d, adding cyanamide for addition reaction, adding aqueous hydrochloric acid solution, cooling and crystallizing to obtain the p-guanidinobenzoic acid hydrochloride.

10. The method for preparing nafamostat mesylate according to claim 9, wherein: In S1-4, the solvent d is a 14 wt% to 17 wt% aqueous solution of hydrochloric acid; In S1-4, the mass ratio of the p-aminobenzoic acid, the solvent d and the cyanamide is 1:(1-10):(1-10); In S1-4, the temperature of the addition reaction is 20°C to 80°C, and the reaction time is 2h to 12h.

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