Preparation method of tiamulin and tiamulin fumarate based on Bunte salt

Abstract

The invention discloses a preparation method of tiamulin and tiamulin fumarate based on Bunte salt, which comprises the following steps: mixing the Bunte salt and pleuromutilin p-toluenesulfonate, reacting at 45-65 DEG C for 3-5 hours to synthesize tiamulin, preparing the Bunte salt through a reaction formula 1, and preparing the pleuromutilin p-toluenesulfonate through a reaction formula 2, the molar ratio of the 2-diethylaminoethanol to the sodium thiosulfate to the chlorination reagent in the reaction formula 1 is 1: (1-1.3): (1-1.5), and the molar ratio of the pleuromutilin to the paratoluensulfonyl chloride to the pyridine in the reaction formula 2 is 1: (1-1.2): (1-1.2); the prepared tiamulin and fumaric acid are used as raw materials for a salt forming reaction, the reaction temperature ranges from 55 DEG C to 65 DEG C, the reaction time ranges from 40 min to 80 min, and after the reaction is finished, the tiamulin fumarate is prepared through cooling, crystallization, centrifugation and drying; the tiamulin fumarate disclosed by the invention is high in content, low in total amount of impurities, few in variety and stable in quality under high-temperature and high-humidity conditions, and the preparation method is simple and easy to operate and good in product quality.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of chemical drugs, and relates to a preparation method of a veterinary raw material drug, in particular to a preparation method of tiamulin and tiamulin fumarate based on Bunte salt. BACKGROUND

[0002] Tiamulin fumarate is a diterpene special antibiotic for livestock and poultry, which is generally obtained by salifying tiamulin and fumaric acid. The antibacterial spectrum of tiamulin fumarate is similar to that of macrolide antibiotics, and mainly targets gram-positive bacteria, mycoplasma, spirochetes, intracellular lawsonia and gram-positive bacteria, and shows strong antibacterial activity. The effect on mycoplasma is better than that of macrolide drugs. Tiamulin fumarate has the characteristics of rapid absorption in the animal body, high drug concentration, wide distribution and low residue. In addition, tiamulin fumarate does not have cross-resistance with other antibiotics, so it is not easy to produce drug resistance. When used at a low dose, tiamulin fumarate can also promote animal growth and improve feed conversion rate. Due to the unique structural characteristics of tiamulin base, tiamulin fumarate has many advantages as a veterinary raw material drug, especially in the aspects of anti-mycoplasma infection and promoting animal growth, and thus tiamulin fumarate occupies an important position in the field of veterinary drugs.

[0003] In the United States patent US4107434 in 1978, it is disclosed that tiamulin is synthesized by reacting truncated pleuromutilin with 2-diethylaminoethanethiol using Pleurotus mutilus for fermentation. However, 2-diethylaminoethanethiol has a very unpleasant odor, and other substitutes for 2-diethylaminoethanethiol are used in subsequent studies, such as using thiourea instead of N,N-diethyl ethylamine to replace 2-diethylaminoethanethiol, or using nucleophilic substitution reaction of thio-truncated pleuromutilin with diethylaminoethane derivatives to generate tiamulin. The above methods all have the disadvantages of long steps, many by-products, and environmental unfriendliness, and therefore it is urgent to develop more practical and efficient preparation methods of tiamulin and tiamulin fumarate. SUMMARY

[0004] The purpose of the present application is to develop a more practical and efficient preparation method of tiamulin and tiamulin fumarate. The present application has carried out in-depth research on the synthesis route and preparation process of tiamulin and tiamulin fumarate.

[0005] The technical scheme adopted by the present application is a preparation method of titramycin based on Bunte salt, and the key lies in that the preparation method shown in reaction formula 3 is that the Bunte salt and the p-toluenesulfonic acid ester of pleuromutilin are mixed and reacted at 45 DEG C to 65 DEG C for 3h to 5h to synthesize the titramycin, the Bunte salt is prepared through reaction formula 1, and the p-toluenesulfonic acid ester of pleuromutilin is prepared through reaction formula 2;

[0006] Reaction formula 1 is as follows:

[0007]

[0008] Reaction formula 2 is as follows:

[0009]

[0010] Reaction formula 3 is as follows:

[0011]

[0012] In reaction formula 1, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and a chlorinating agent is 1:1 to 1.3:1 to 1.5.

[0013] In reaction formula 2, the molar ratio of pleuromutilin, p-toluenesulfonyl chloride and pyridine is 1:1 to 1.2:1 to 1.2.

[0014] The preparation method of titramycin fumarate based on Bunte salt is a salt formation reaction of titramycin and fumaric acid according to reaction formula 4, and the key lies in that the titramycin is synthesized by the preparation method, and the reaction

[0015] Formula 4 is as follows:

[0016]

[0017] Further, the reaction temperature of the salt formation reaction is 55 DEG C to 65 DEG C, the reaction time of the salt formation reaction is 40 min to 80 min, after the salt formation reaction is completed, the titramycin fumarate is prepared after cooling, crystallization, centrifugation and drying.

[0018] Further, the salt formation reaction needs to add an organic solvent C, and the organic solvent C is any one or a combination of methanol, ethanol or isopropanol.

[0019] Specifically, the specific steps of the preparation method are as follows:

[0020] S1 step, preparation of Bunte salt:

[0021] 2-diethylaminoethanol and chlorinating reagent are reacted at room temperature for 0.5h-2h to prepare a 2-diethylaminoethyl chloride hydrochloride solution, and then sodium thiosulfate is added to the 2-diethylaminoethyl chloride hydrochloride solution to react at 60℃-70℃ for 1.5h-3.5h to prepare a Bunte salt, and the prepared Bunte salt is a Bunte salt solution or a Bunte salt solid obtained by filtration and crystallization;

[0022] S2 step, preparation of pleuromutilin p-toluenesulfonate:

[0023] Pleuromutilin and pyridine are added to an organic solvent B, and p-toluenesulfonyl chloride is added dropwise while controlling the reaction temperature to 20℃-30℃, and reacted for 2h-4h to prepare pleuromutilin p-toluenesulfonate, and the prepared pleuromutilin p-toluenesulfonate is a pleuromutilin p-toluenesulfonate solution.

[0024] S3 step, preparation of fumoxicin fumarate:

[0025] The Bunte salt and the pleuromutilin p-toluenesulfonate are mixed and reacted at 45℃-65℃ for 3h-5h, and then an organic solvent C and fumaric acid are added to perform a salt formation reaction, and after cooling, crystallization, centrifugation, water washing, and drying, the fumoxicin fumarate is prepared.

[0026] Further, in the S1 step, 2-diethylaminoethanol and chlorinating reagent can be reacted in an organic solvent A, and the amount of the organic solvent A used is 0.8L-1.1L per mole of 2-diethylaminoethanol.

[0027] Further, the organic solvent A is any one or a combination of dichloromethane, chlorobenzene, chloroform, 1,2-dichloroethane, acetone, tetrahydrofuran, ethyl acetate, or 2,2-dimethyltetrahydrofuran, and after the 2-diethylaminoethyl chloride hydrochloride solution is prepared in the S1 step, the organic solvent A can be removed by concentration.

[0028] Further, in the S1 step, the tail gas can be absorbed with an aqueous base or collected.

[0029] Specifically, the organic solvent B is any one or a combination of ethyl acetate, tetrahydrofuran, dichloromethane, chloroform, acetone, methyl acetate, ethyl formate, or methyl isobutyl ketone, and the amount of the organic solvent B used is 0.5L-0.8L per mole of pleuromutilin.

[0030] Preferably, the chlorinating agent is any one of chlorine, hydrogen chloride, thionyl chloride, phosphorus pentachloride and phosphorus trichloride; the sodium thiosulfate is added together with water and methanol, the volume ratio of water to methanol is 1:3-4, and the total volume of water and methanol used per mole of sodium thiosulfate is 3-4 L; the drying is carried out using anhydrous sodium sulfate or anhydrous magnesium sulfate; and the water washing is carried out using any one or a combination of ethyl acetate, dichloromethane, chloroform, ethyl formate, methyl isobutyl ketone or methyl tert-butyl ether.

[0031] Compared with the prior art, the present application has the following advantages:

[0032] The present application studies a preparation method of tiamulin and tiamulin fumarate based on Bunte salt. The Bunte salt, i.e. alkyl thiosulfate, is generally composed of two parts, i.e. alkyl (R) and thiosulfate ion (S2O3 2- ), from the structure. Among them, the alkyl is mainly various hydrocarbon groups such as methyl (CH3) and ethyl (C2H5), and these alkyl groups of different structures and sizes will affect the physical and chemical properties of the Bunte salt.

[0033] In the present application, the 2-diethylaminoethanol is prepared into the corresponding Bunte salt by using inorganic salt sodium thiosulfate as a sulfuration reagent, the main structure of which is amine group and thiosulfate ion, which can provide the long branched chain part of tiamulin. In the present application, the prepared Bunte salt is mixed with pleuromutilin p-toluenesulfonate, and tiamulin can be synthesized under the relatively mild conditions of 45-65°C. The synthesis step does not need to involve special catalysts and special acid-base environment, and the solvent used is also a safer and more environmentally friendly alcohol solvent. However, the solvent used in the prior art for this reaction is generally methyl isobutyl ketone, which can cause inhibition and anesthesia of the central nervous system, stimulate the respiratory tract when inhaled at high concentration, cause symptoms such as nausea, vomiting, loss of appetite, abdominal pain, etc., and also pollute the environment through air, water and soil, and have toxic effects on aquatic organisms and terrestrial organisms. It can be seen that the process of the present application is relatively safe and environmentally friendly. In the present application, if tiamulin fumarate is further prepared, it does not need to be separated and purified, and fumaric acid can be directly added to the system for salt formation. In addition, the inorganic salt sodium thiosulfate used in the present application is cheap and low in cost.

[0034] More importantly, the product sample prepared by the synthetic route of the present application has high content and low total amount of impurities, and the product content reaches as high as 99.7%, which is better than the control sample prepared by the synthetic route of the prior art. In addition, the types of impurities in the product sample prepared by the present application are also reduced, and only 4 types of impurities are contained in the sample synthesized under the optimal process, while 7 types of impurities are contained in the control samples of the two prior art processes.

[0035] Under the conditions of high temperature and high humidity, the stability of the sample prepared by the present application is stable, and after the end of the investigation period, the content of the product sample is still much higher than the requirement of the relevant quality standard, and the impurities of the product sample are still much lower than the relevant quality standard. Although the control sample also meets the requirements of the relevant quality standard, it is closer to the limit of the requirement.

[0036] In summary, the preparation method of thiamphenicol and thiamphenicol fumarate of the present application is simple and easy to operate, and the product quality is good. Not only is it a green, environmentally friendly and economic synthesis strategy, but it is also more conducive to drug quality and safety, and has good commercialization prospects. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The high performance liquid chromatogram of the ester sample 1.

[0038] Figure 2 The high performance liquid chromatogram of the ester sample 2.

[0039] Figure 3 The high performance liquid chromatogram of the ester sample 3.

[0040] Figure 4 The high performance liquid chromatogram of the ester sample 4.

[0041] Figure 5 The high performance liquid chromatogram of the ester sample 5.

[0042] Figure 6 The infrared spectrum of the product sample 1.

[0043] Figure 7 The infrared spectrum of the product sample 2.

[0044] Figure 8 The infrared spectrum of the product sample 3.

[0045] Figure 9 The infrared spectrum of the product sample 4.

[0046] Figure 10 The infrared spectrum of the product sample 5.

[0047] Figure 11 The high performance liquid chromatogram of the product sample 1.

[0048] Figure 12 HPLC of product sample 2.

[0049] Figure 13 HPLC of product sample 3.

[0050] Figure 14 HPLC of product sample 4.

[0051] Figure 15 HPLC of product sample 5.

[0052] Figure 16 HPLC of product control 1.

[0053] Figure 17 HPLC of product control 2. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present application.

[0055] The unmarked specific conditions in the embodiments can be carried out according to the conventional conditions; the used reagents or instruments without marked manufacturers are all the conventional products which can be obtained by market purchase.

[0056] In the embodiments of the present application, the tiamulin is prepared according to the following reaction process, and the tiamulin fumarate is prepared by using the prepared tiamulin and fumaric acid as raw materials.

[0057] The reaction formula for preparing the tiamulin is as follows:

[0058]

[0059] The reaction formula for preparing the tiamulin fumarate is as follows:

[0060]

[0061] In the embodiments one to eight, the step S1 is studied:

[0062] Embodiment one

[0063] In a dry reaction bottle, 60.5 mmol of thionyl chloride is added, and 55 mmol of 2-diethylaminoethanol is added dropwise at room temperature;

[0064] The temperature of the reaction system rose to refluxing state during the dropwise addition of 2-diethylaminoethanol, and the tail gas generated was absorbed by alkaline water;

[0065] After the dropwise addition of 2-diethylaminoethanol was completed, the reaction was carried out at room temperature for 1.5 h to prepare a 2-diethylaminoethyl chloride hydrochloride solution;

[0066] Then, 59 mmol of sodium thiosulfate was added to the reaction bottle;

[0067] The reaction was continued at 65°C for 2 h to prepare the Bunte salt, which was a Bunte salt solution and was recorded as Bunte salt sample 1.

[0068] In this embodiment, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and thionyl chloride was 1:1.07:1.10.

[0069] Example Two

[0070] S1-1, 60.5 mL of dichloromethane and 55 mmol of thionyl chloride were added to a dry reaction bottle, and 55 mmol of 2-diethylaminoethanol was added dropwise at room temperature;

[0071] S1-2, the temperature of the reaction system rose to refluxing state during the dropwise addition of 2-diethylaminoethanol, and the tail gas generated was absorbed by alkaline water;

[0072] S1-3, after the dropwise addition of 2-diethylaminoethanol was completed, the reaction was carried out at room temperature for 2 h, and after the reaction was completed, the organic solvent in the 2-diethylaminoethyl chloride hydrochloride solution was removed by concentration;

[0073] S1-4, 60.5 mmol of sodium thiosulfate was added to the reaction bottle;

[0074] S1-5, the reaction was continued at 70°C for 1.5 h, and the Bunte salt solid obtained by filtration and crystallization was recorded as Bunte salt sample 2.

[0075] In this embodiment, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and thionyl chloride was 1:1.10:1.00.

[0076] Example Three

[0077] S1-1, 44 mL of a mixed solution of dichloromethane and tetrahydrofuran was added to a dry reaction bottle, the volume ratio of dichloromethane and tetrahydrofuran was 1:1, 66 mmol of thionyl chloride was added, and 55 mmol of 2-diethylaminoethanol was added dropwise at room temperature;

[0078] S1-2, the temperature of the reaction system rose to refluxing state during the dropwise addition of 2-diethylaminoethanol, and the tail gas generated was absorbed by alkaline water;

[0079] S1-3, after the completion of the drop of 2-diethylaminoethanol, the reaction was carried out at room temperature for 1.5 h, after the reaction was completed, the organic solvent in the 2-diethylaminoethyl chloride hydrochloride solution was removed by concentration;

[0080] S1-4, 55 mmol of sodium thiosulfate, 55 mL of water and 165 mL of methanol were added to the reaction bottle again;

[0081] S1-5, continue to react at 60°C for 3.5 h, filter and crystallize the obtained Bunte salt solid, marked as Bunte salt sample 3.

[0082] The molar ratio of 2-diethylaminoethanol, sodium thiosulfate and thionyl chloride in this example is 1:1.00:1.20.

[0083] Example Four

[0084] S1-1, in a dry reaction bottle, 50 mL of dichloromethane and 60 mmol of thionyl chloride were added, and 55 mmol of 2-diethylaminoethanol was added dropwise at room temperature;

[0085] S1-2, as the 2-diethylaminoethanol was added, the temperature of the reaction system rose to reflux state, and the tail gas generated was absorbed by alkaline water;

[0086] S1-3, after the completion of the drop of 2-diethylaminoethanol, the reaction was carried out at room temperature for 1.5 h, after the reaction was completed, the organic solvent in the 2-diethylaminoethyl chloride hydrochloride solution was removed by concentration;

[0087] S1-4, 60 mmol of sodium thiosulfate, 50 mL of water and 150 mL of methanol were added to the reaction bottle again;

[0088] S1-5, continue to react at 65°C for 2h, filter and crystallize the obtained Bunte salt solid, marked as Bunte salt sample 4.

[0089] The molar ratio of 2-diethylaminoethanol, sodium thiosulfate and thionyl chloride in this example is 1:1.09:1.09.

[0090] Example Five

[0091] S1-1, in a dry reaction bottle, 50 mL of dichloromethane and 60 mmol of thionyl chloride were added, and 55 mmol of 2-diethylaminoethanol was added dropwise at room temperature;

[0092] S1-2, as the 2-diethylaminoethanol was added, the temperature of the reaction system rose to reflux state, and the tail gas generated was collected.

[0093] S1-3, after the completion of the dropwise addition of 2-diethylaminoethanol, the reaction was continued at room temperature for 1.5 h, and after the completion of the reaction, the organic solvent in the 2-diethylaminoethyl chloride hydrochloride solution was removed by concentration;

[0094] S1-4, 60 mmol of sodium thiosulfate, 33 mL of water and 132 mL of methanol were further added to the reaction bottle;

[0095] S1-5, the reaction was continued at 65°C for 2 h, and the Bunte salt solid obtained by filtration and crystallization was recorded as Bunte salt sample 5.

[0096] In this example, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and phosphorus pentachloride was 1:1.09:1.09.

[0097] Example Six

[0098] S1-1, in a dry reaction bottle, 50 mL of chloroform and 60 mmol of phosphorus trichloride were added, and 55 mmol of 2-diethylaminoethanol was added dropwise at room temperature;

[0099] S1-2, as the 2-diethylaminoethanol was being added dropwise, the temperature of the reaction system rose to reflux, and the tail gas generated was absorbed with alkaline water;

[0100] S1-3, after the completion of the dropwise addition of 2-diethylaminoethanol, the reaction was continued at room temperature for 1.5 h, and after the completion of the reaction, the organic solvent in the 2-diethylaminoethyl chloride hydrochloride solution was removed by concentration;

[0101] S1-4, 71 mmol of sodium thiosulfate was further added to the reaction bottle;

[0102] S1-5, the reaction was continued at 65°C for 2 h, and the Bunte salt solid obtained by filtration and crystallization was recorded as Bunte salt sample 6.

[0103] In this example, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and phosphorus trichloride was 1:1.29:1.09.

[0104] Example Seven

[0105] S1-1, in a dry reaction bottle, 50 mL of 1,2-dichloroethane and acetone were added, the volume ratio of 1,2-dichloroethane to acetone was 1:1.2, 82.5 mmol of chlorine gas was introduced, and 55 mmol of 2-diethylaminoethanol was added dropwise at room temperature;

[0106] S1-2, as the 2-diethylaminoethanol was being added dropwise, the temperature of the reaction system rose to reflux, and the tail gas generated was absorbed with alkaline water;

[0107] S1-3, after the completion of the dropwise addition of 2-diethylaminoethanol, the reaction was continued at room temperature for 1.5 h, and after the completion of the reaction, the organic solvent in the 2-diethylaminoethyl chloride hydrochloride solution was removed by concentration;

[0108] S1-4, 65 mmol of sodium thiosulfate, 50 mL of water and 150 mL of methanol were further added to the reaction bottle;

[0109] S1-5, the reaction was continued at 65°C for 2 h, and the Bunte salt solid obtained by filtration and crystallization was recorded as Bunte salt sample 7.

[0110] In this example, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and hydrogen chloride was 1:1.09:1.50.

[0111] Example Eight

[0112] S1-1, in a dry reaction bottle, 50 mL of chlorobenzene and 2,2-dimethyltetrahydrofuran were added, the volume ratio of chlorobenzene and 2,2-dimethyltetrahydrofuran was 1:0.6, 82.5 mmol of hydrogen chloride gas was introduced, and 55 mmol of 2-diethylaminoethanol was added dropwise at room temperature;

[0113] S1-2, during the dropwise addition of 2-diethylaminoethanol, the temperature of the reaction system rose to reflux, and the tail gas generated was absorbed with alkaline water;

[0114] S1-3, after the completion of the dropwise addition of 2-diethylaminoethanol, the reaction was continued at room temperature for 1.5 h, and after the completion of the reaction, the organic solvent in the 2-diethylaminoethyl chloride hydrochloride solution was removed by concentration;

[0115] S1-4, 60 mmol of sodium thiosulfate, 50 mL of water and 150 mL of methanol were further added to the reaction bottle;

[0116] S1-5, the reaction was continued at 65°C for 2 h, and the Bunte salt solid obtained by filtration and crystallization was recorded as Bunte salt sample 8.

[0117] In this example, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and hydrogen chloride was 1:1.09:1.50.

[0118] In Examples Nine to Twelve, the S2 step was studied:

[0119] Example Nine

[0120] In the reaction bottle, 40 mL of chloroform was added, then 55 mmol of pleuromutilin and 60 mmol of pyridine were added, 60 mmol of p-toluenesulfonyl chloride was slowly added dropwise, the reaction temperature was controlled at 25°C, after the completion of the dropwise addition of p-toluenesulfonyl chloride, the reaction was continued for 3 h, and p-toluenesulfonate of pleuromutilin was prepared, which was recorded as ester sample 1.

[0121] In this embodiment, the molar ratio of pleuromutilin, p-toluenesulfonyl chloride and pyridine is 1:1.09:1.09.

[0122] Example Ten

[0123] In a reaction bottle, 27.5 mL of a mixed solvent of ethyl acetate and tetrahydrofuran with a volume ratio of 1:1 was added, then 55 mmol of pleuromutilin and 66 mmol of pyridine were added, 55 mmol of p-toluenesulfonyl chloride was slowly added dropwise, the reaction temperature was controlled at 20°C, and after the addition of p-toluenesulfonyl chloride was completed, the reaction was carried out for 4 h to prepare p-toluenesulfonate of pleuromutilin, which was recorded as ester sample 2.

[0124] In this embodiment, the molar ratio of pleuromutilin, p-toluenesulfonyl chloride and pyridine is 1:1.00:1.20.

[0125] Example Eleven

[0126] In a reaction bottle, 44 mL of a mixed solvent of acetone and methyl acetate with a volume ratio of 1:1.5 was added, then 55 mmol of pleuromutilin and 55 mmol of pyridine were added, 66 mmol of p-toluenesulfonyl chloride was slowly added dropwise, the reaction temperature was controlled at 30°C, and after the addition of p-toluenesulfonyl chloride was completed, the reaction was carried out for 2 h to prepare p-toluenesulfonate of pleuromutilin, which was recorded as ester sample 3.

[0127] In this embodiment, the molar ratio of pleuromutilin, p-toluenesulfonyl chloride and pyridine is 1:1.20:1.00.

[0128] Example Twelve

[0129] In a reaction bottle, 38.5 mL of a mixed solvent of dichloromethane, ethyl formate and methyl isobutyl ketone with a volume ratio of 1:1.5:0.5 was added, then 55 mmol of pleuromutilin and 58 mmol of pyridine were added, 58 mmol of p-toluenesulfonyl chloride was slowly added dropwise, the reaction temperature was controlled at 25°C, and after the addition of p-toluenesulfonyl chloride was completed, the reaction was carried out for 3 h to prepare p-toluenesulfonate of pleuromutilin, which was recorded as ester sample 4.

[0130] In this embodiment, the molar ratio of pleuromutilin, p-toluenesulfonyl chloride and pyridine is 1:1.00:1.05.

[0131] In Examples Thirteen to Sixteen, the S3 step was studied:

[0132] Example Thirteen

[0133] The preparation process of Bunte salt used in this example is the same as that in Example One, and the preparation process of pleuromutilin p-toluene sulfonate is the same as that in Example Nine.

[0134] The Bunte salt and pleuromutilin p-toluene sulfonate are mixed and reacted at 55°C for 4h, 55mmol of fumaric acid and 5mL of methanol are added, and the salt formation reaction is carried out at 60°C for 60min. After cooling, crystallization, centrifugation, ethyl acetate and water washing, and anhydrous sodium sulfate drying, fumaric acid tiamulin is prepared, which is recorded as product sample 1.

[0135] Example Fourteen

[0136] The preparation process of Bunte salt used in this example is the same as that in Example Four, and the preparation process of pleuromutilin p-toluene sulfonate is the same as that in Example Nine.

[0137] The Bunte salt and pleuromutilin p-toluene sulfonate are mixed and reacted at 55°C for 4h, 55mmol of fumaric acid and 5mL of methanol are added, and the salt formation reaction is carried out at 60°C for 60min. After cooling, crystallization, centrifugation, ethyl acetate and water washing, and anhydrous sodium sulfate drying, fumaric acid tiamulin is prepared, which is recorded as product sample 1.

[0138] Example Fifteen

[0139] The preparation process of Bunte salt used in this example is the same as that in Example Four, and the preparation process of pleuromutilin p-toluene sulfonate is the same as that in Example Nine.

[0140] The Bunte salt and pleuromutilin p-toluene sulfonate are mixed and reacted at 55°C for 4h, 55mmol of fumaric acid and 5mL of methanol are added, and the salt formation reaction is carried out at 60°C for 60min. After cooling, crystallization, centrifugation, ethyl acetate and water washing, and anhydrous sodium sulfate drying, fumaric acid tiamulin is prepared, which is recorded as product sample 1.

[0141] Example Sixteen

[0142] The preparation process of Bunte salt used in this example is the same as that in Example Four, and the preparation process of pleuromutilin p-toluene sulfonate is the same as that in Example Nine.

[0143] The Bunte salt and pleuromutilin p-toluene sulfonate are mixed and reacted at 55°C for 4h, 55mmol of fumaric acid and 5mL of methanol are added, and the salt formation reaction is carried out at 60°C for 60min. After cooling, crystallization, centrifugation, ethyl acetate and water washing, and anhydrous sodium sulfate drying, fumaric acid tiamulin is prepared, which is recorded as product sample 1.

[0144] Example Seventeen (Large-scale production test)

[0145] S1 step, preparation of Bunte salt:

[0146] S1-1, in a porcelain reaction kettle, 3000L of chlorobenzene and 400kg of thionyl chloride were added, and 352kg of 2-diethylaminoethanol was added dropwise at room temperature;

[0147] S1-2, as the 2-diethylaminoethanol was added dropwise, the temperature of the reaction system rose to reflux, and SO2 and HCl mixed gas was generated during the reaction of thionyl chloride, and the tail gas was collected;

[0148] S1-3, after the addition of 2-diethylaminoethanol was completed, the reaction was carried out at room temperature for 1.5h, and after the reaction was completed, the organic solvent in the 2-diethylaminochloroethane hydrochloride solution was removed by concentration;

[0149] S1-4, 518kg of sodium thiosulfate was added to the reaction bottle;

[0150] S1-5, continue to react at 65℃ for 2h, filter and crystallize to obtain Bunte salt solid, marked as Bunte salt sample 9.

[0151] In this example, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and chlorinating agent is 1:1.27:1.12; 0.9L of chlorobenzene is used per mole of 2-diethylaminoethanol.

[0152] S2 step, preparation of pleuromutilin p-toluenesulfonate:

[0153] In the reaction kettle, 400L of chloroform was added, then 208kg of pleuromutilin and 480L of pyridine were added, and 114kg of p-toluenesulfonyl chloride was slowly added dropwise, and the reaction was carried out at room temperature. After the addition of p-toluenesulfonyl chloride was completed, the reaction was carried out for 2h, and the concentration of pleuromutilin p-toluenesulfonate was concentrated to 80%, and pleuromutilin p-toluenesulfonate was prepared, marked as ester sample 5.

[0154] In this step, the molar ratio of pleuromutilin, p-toluenesulfonyl chloride and pyridine is 1:1.09:1.09; 0.73L of chloroform is used per mole of pleuromutilin.

[0155] S3 step, preparation of fumoxicin fumarate:

[0156] In the reaction kettle, 90kg of the prepared Bunte salt sample 9 and 240kg of the prepared ester sample 5 were added and stirred, and reacted at 65℃ for 4h, then 52kg of fumaric acid and 40L of methanol were added, and the salt reaction was carried out at 60℃ for 60min, then cooled, crystallized, centrifuged, washed with ethyl acetate and water, and dried with anhydrous sodium sulfate, to prepare fumoxicin fumarate, marked as product sample 5.

[0157] Comparative Example 1

[0158] The modified pleuromutilin is reacted with p-toluenesulfonyl chloride, and the specific process is as follows:

[0159] S1, 40 mL of methyl isobutyl ketone is added to a reaction bottle, then 55 mmol of pleuromutilin and concentrated nitric acid are added, the reaction temperature is controlled at 25℃, and the pleuromutilin is subjected to ring opening reaction for 20 min to obtain the oxide of pleuromutilin;

[0160] S2, 60 mmol of p-toluenesulfonyl chloride is added dropwise to the above reaction bottle, the reaction temperature is controlled at 50℃, and the pH value is controlled under alkaline condition, after the addition of p-toluenesulfonyl chloride is completed, the reaction is carried out for 1 h;

[0161] S3, 2 mmol of tetrabutylammonium bromide and 55 mmol of diethylaminoethyl mercaptan are added to the above reaction bottle, the pH value is controlled under alkaline condition, the reaction temperature is controlled at 50℃, and the reaction is carried out for 1 h, then 55 mmol of fumaric acid and 8 mL of methanol are added, and the salt formation reaction is carried out at 60℃ for 60 min, after cooling, crystallization, centrifugation, ethyl acetate washing, and drying with anhydrous sodium sulfate, fumagillin fumarate is prepared, which is recorded as control 1.

[0162] Comparative Example 2

[0163] In this comparative example, the thio-pleuromutilin is subjected to nucleophilic substitution with diethylaminoethane derivative, and the specific process is as follows:

[0164] S1, 40 mL of methyl isobutyl ketone is added to a reaction bottle, then 55 mmol of pleuromutilin and 60 mmol of pyridine are added, 60 mmol of p-toluenesulfonyl chloride is slowly added dropwise, the reaction temperature is controlled at 25℃, and the reaction is carried out for 3 h after the addition of p-toluenesulfonyl chloride is completed;

[0165] S2, 57 mmol of thiourea is added to the above reaction bottle, and the reaction is carried out at 60℃ for 1.5 h, then 22 mmol of sodium pyrosulfite and 165 g of water are added, the reaction is carried out at 90℃ for 1 h under reflux, and after the water layer is removed, the methyl isobutyl ketone solution of thio-pleuromutilin is obtained.

[0166] S3, 75 mmol of 2-diethylamino-1-chloroethane hydrochloride, 75 mmol of NaOH, and 350 g of water are added to the prepared methyl isobutyl ketone solution of thio-pleuromutilin, the reaction is carried out at 60℃ for 2 h under stirring, the water layer is removed, then 55 mmol of fumaric acid and 8 mL of methanol are added, and the salt formation reaction is carried out at 60℃ for 60 min, after cooling, crystallization, centrifugation, ethyl acetate washing, and drying with anhydrous sodium sulfate, fumagillin fumarate is prepared, which is recorded as control 2.

[0167] Analysis and test

[0168] (1) The purity of Bunte salt samples 2-9 was determined by titration, and the purity of ester samples 1-5 was determined by HPLC, each sample was tested in triplicate, and the average value was taken, and the results are shown in Table 1, and the HPLC chromatograms of the ester samples are shown in Figures 1-5 .

[0169] Bunte salt sample 1 is a solution, and the purity test result has no reference significance.

[0170] Table 1: Purity summary table of ester samples

[0171]

[0172]

[0173] As can be seen from the results in Table 1, the Bunte salt samples and ester samples prepared by the present application have high purity, less impurities and stable quality, which can reduce the high impurity problem of tylosin product caused by high impurities of starting materials.

[0174] Among them, Bunte salt sample 4 and ester sample 1 have the highest content, indicating that the reaction steps studied in Example Four and Example Nine are the most optimal, and subsequent step and production test research can be carried out on the basis of this process.

[0175] (2) According to the method recorded in the European Pharmacopoeia, the quality of the fumaric acid tylosin samples, i.e. product samples 1-5 and control samples 1 and 2, was analyzed, and the results are shown in Tables 2 and 3.

[0176] Among them, the infrared spectra of product samples 1-5 are shown in Figures 6-10 , and the HPLC spectra of product samples 1-5 and control samples 1 and 2 are shown in the attached Figures 11-17 .

[0177] Table 2: Quality test results of fumaric acid tylosin samples and control samples

[0178]

[0179] Note: 1, in Table 2, the infrared spectrum of the test sample should be consistent with the reference spectrum; the retention time of fumaric acid tylosin is consistent with the standard. 2, in the field of drug analysis (especially in the purity detection of HPLC), the sum of content and total impurities is greater than 100%, which is a normal phenomenon, because different calculation criteria lead to the results of content, total impurities and single impurities in Table 2 meet the requirements of authoritative pharmacopoeias such as Chinese Pharmacopoeia and European Pharmacopoeia (Tables 3-5 same).

[0180] Table 3: Impurity analysis of fumaric acid tylosin product samples and control samples

[0181]

[0182]

[0183] Note: The data in Table 3 are obtained from the HPLC spectrum analysis of the corresponding sample or control, and the peak area percentage is used as the basis for evaluating the content of each impurity; each sample to be tested is tested in triplicate, and the average value is used as the evaluation result, which is recorded in Table 3. If only one test detects a certain impurity in the three parallel tests, the detected impurity result is used as the evaluation result.

[0184] As can be seen from the results in Table 3, compared with the control samples 1 and 2, the sample prepared by the present application has fewer types of impurities and relatively lower content. Among them, only four impurities are detected in the sample prepared by product sample 2, and the total amount of impurities is about half of that of control samples 1 or 2.

[0185] (III) Stability Investigation

[0186] Under the accelerated stability investigation conditions (temperature 40℃±2℃, relative humidity 85%), the sample prepared by the present application and the control samples were subjected to stability investigation, and were tested at 1 month, 2 months, 3 months and 6 months, respectively. The results of the stability investigation at 3 months and 6 months are shown in Table 4 and Table 5.

[0187] Table 4: Summary table of stability investigation results of tylosin fumurate product sample and control samples for 3 months

[0188]

[0189] Table 5: Summary table of stability investigation results of tylosin fumurate product sample and control samples for 6 months

[0190]

[0191] As can be seen from the results in Table 4 and Table 5, the sample prepared by the present application is placed under the accelerated stability investigation conditions for 6 months, and the quality stability of the tylosin fumurate product sample prepared by the present application is good. After being stored in a high temperature and high humidity environment for 6 months, the product quality is still higher than the requirements of the relevant standards.

Claims

1. Process for the preparation of tylosin based on Bunte salts, characterized in that, The preparation method is shown in reaction formula 3, and the titron is synthesized by mixing Bunte salt and pleuromutilin p-toluenesulfonate at 45-65 DEG C for 3-5 h, the Bunte salt is prepared by reaction formula 1, and the pleuromutilin p-toluenesulfonate is prepared by reaction formula 2; Reaction formula 1 is: Reaction formula 2 is: Reaction formula 3 is: In reaction formula 1, the molar ratio of 2-diethylaminoethanol, sodium thiosulfate and chlorinating agent is 1:1-1.3:1-1.5; In reaction formula 2, the molar ratio of pleuromutilin, p-toluenesulfonyl chloride and pyridine is 1:1-1.2:1-1.

2.

2. A method for preparing tylosin furoate based on Bunte salt, according to the reaction formula 4, carrying out a salt formation reaction with tylosin and furoic acid as raw materials, characterized in that, The titron is synthesized by the preparation method in claim 1, and reaction formula 4 is:

3. The process for the preparation of tylosin furoate based on Bunte salts according to claim 2, characterized in that, The reaction temperature of the salting reaction is 55-65 DEG C, the reaction time of the salting reaction is 40-80 min, after the salting reaction is completed, the fumaric acid titron is prepared by cooling, crystallization, centrifugation, and drying.

4. The process for preparing Bunte salt based tylosin furoate according to claim 2, characterized in that, An organic solvent C needs to be added in the salting reaction process, and the organic solvent C is any one or combination of methanol, ethanol or isopropanol.

5. The process for the preparation of Bunte salt based tylosin furoate according to any one of claims 2 to 4, characterized in that, The specific steps of the preparation method are: S1 step, preparation of Bunte salt: 2-diethylaminoethanol and chlorinating agent are reacted at room temperature for 0.5-2 h to prepare 2-diethylaminochloroethane hydrochloride solution, then sodium thiosulfate is added to the 2-diethylaminochloroethane hydrochloride solution, and the mixture is reacted at 60-70 DEG C for 1.5-3.5 h to prepare Bunte salt, and the prepared Bunte salt is Bunte salt solution or Bunte salt solid obtained by filtration and crystallization; S2 step, preparation of pleuromutilin p-toluenesulfonate: Pleuromutilin and pyridine are added in organic solvent B, and p-toluenesulfonyl chloride is added dropwise, the reaction temperature is controlled at 20-30 DEG C, and the reaction is carried out for 2-4 h to prepare pleuromutilin p-toluenesulfonate, and the prepared pleuromutilin p-toluenesulfonate is pleuromutilin p-toluenesulfonate solution; S3 step, preparation of fumaric acid titron: Bunte salt and pleuromutilin p-toluenesulfonate are mixed, and the mixture is reacted at 45-65 DEG C for 3-5 h, then organic solvent C and fumaric acid are added to carry out salting reaction, and after cooling, crystallization, centrifugation, water washing and drying, the fumaric acid titron is prepared.

6. The method of preparing Bunte salt-based tylosin furoate according to claim 5, characterized in that, In the S1 step, 2-diethylaminoethanol and chlorinating agent can be reacted in organic solvent A, and the amount of organic solvent A used is 0.8-1.1 L per mole of 2-diethylaminoethanol.

7. The method of preparing Bunte salt-based tylosin furoate according to claim 5, characterized in that, The organic solvent A is any one or combination of dichloromethane, chlorobenzene, chloroform, 1,2-dichloroethane, acetone, tetrahydrofuran, ethyl acetate or 2,2-dimethyltetrahydrofuran; in the S1 step, after the 2-diethylaminochloroethane hydrochloride solution is prepared, the organic solvent A can be removed by concentration.

8. The method of preparing Bunte salt-based tylosin furoate according to claim 5, characterized in that, In the S1 step, tail gas can be absorbed by alkaline water or collected.

9. The method of preparing Bunte salt-based tylosin furoate according to claim 5, characterized in that, The organic solvent B is any one or combination of ethyl acetate, tetrahydrofuran, dichloromethane, chloroform, acetone, methyl acetate, ethyl formate or methyl isobutyl ketone, and the amount of the organic solvent B used is 0.5L-0.8L per mole of pleuromutilin.

10. The method of preparing Bunte salt based tylosin furoate according to claim 5, characterized in that, The chlorinating agent is any one of chlorine, hydrogen chloride, thionyl chloride, phosphorus pentachloride and phosphorus trichloride; when sodium thiosulfate is added, water and methanol can be added simultaneously, the volume ratio of water to methanol is 1:3-4, and the total volume of water and methanol used per mole of sodium thiosulfate is 3L-4L; the drying is drying using anhydrous sodium sulfate or anhydrous magnesium sulfate; the water washing uses any one or combination of ethyl acetate, dichloromethane, chloroform, ethyl formate, methyl isobutyl ketone or methyl tert-butyl ether.

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