Process for the preparation of ertapenem amide and its use in the study of the quality of the preparation

Abstract

The thiol group of the side chain of ertapenem is protected by acetyl to obtain intermediate 1, then the corresponding amine is reacted to obtain intermediate 2, the acetyl protection of the thiol group of intermediate 2 is removed under the action of a base to obtain intermediate 3, intermediate 3 is reacted with MAP to obtain intermediate 4, and the target compound ertapenem amide is obtained by hydrogenation and deprotection of intermediate 4. The ertapenem sodium lyophilized powder injection prepared by different processes is detected by taking ertapenem amide as an impurity external standard, and the content of ertapenem amide is all less than 0.1%.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of a carbapenem antibiotic derivative, belonging to the field of medicinal chemistry. BACKGROUND

[0002] Ertapenem sodium was developed by Merck Company, and was listed in the United States and Europe in November 2001 and April 2002 respectively, and was listed in China in 2005. Ertapenem sodium is a carbapenem antibiotic, and its structural formula is as follows:

[0003] .

[0004] It can be effectively used for moderate and severe infections caused by bacterial multiple drug resistance, and has strong antibacterial activity against cephalosporin-resistant ESBLs or AmpC and penicillin-resistant Streptococcus pneumoniae, and is considered as an important defense line against infection in humans. With the increasingly serious problem of bacterial drug resistance, people pay more and more attention to carbapenem antibiotics.

[0005] Ertapenem sodium is obtained by condensation of the side chain of ertapenem with MAP under the action of an organic base (amine), and then hydrogenation and deprotection. Since the organic base (DIPEA, tetramethyl guanidine, etc.) in the condensation step is an essential reagent, it is very likely that ertapenem amide will be produced in the preparation process of ertapenem sodium.

[0006] .

[0007] When R and R' are both methyl, the amide produced is the known impurity Q controlled in the USP ertapenem sodium variety, with a limit of <0.1%. At present, there is no reported synthesis literature of this kind of amide compound.

[0008] Due to the characteristics of the condensate and ertapenem sodium with carbapenem structure, the stability is poor, and there is obvious degradation when stored at low temperature. At the same time, since the condensate and ertapenem sodium also contain hydroxyl groups (ertapenem sodium also contains an additional carboxyl group) in their structures, it is more difficult to carry out amide reaction directly on the condensate or ertapenem sodium. Therefore, it is of great significance for the quality research and control of ertapenem sodium to develop a stable and easy-to-operate synthesis route of ertapenem amide. SUMMARY

[0009] According to the condensate prepared from the side chain of ertapenem and MAP, the carboxylic acid is located on the side chain of ertapenem, and the side chain is relatively stable, so the inventors try to use the side chain of ertapenem to carry out the amidation reaction first, but when developing a suitable reaction condition, it is found that the thiol group of the side chain of ertapenem is more likely to react with the carboxylic acid, resulting in the difficulty in generating the target amide. Therefore, the inventors try to first protect the thiol group with acetyl, and then further carry out the amidation reaction. Isopropyl acrylate, propyl acrylate, and acetic anhydride are used as acetylation reagents; pyridine, acetyl chloride, 30%-60% perchloric acid, and p-toluenesulfonic acid are used as acetylation catalysts to achieve good acetylation effect.

[0010] When using the acetyl-protected ertapenem side chain (intermediate 1) to carry out amidation, the inventors first try to use thionyl chloride or oxalyl chloride to prepare an acyl chloride, and then react with an organic base, but it is found in the test process that a large amount of thiol and carboxylic acid thioester impurities are still generated, indicating that this route is easy to destroy the acetyl protection.

[0011] In order to develop a mild reaction condition route, the inventors try to add a condensing agent to promote amidation. When CDI is used to form an active ester, and a carbodiimide condensing agent (DCC combined with DMAP, EDC hydrochloride combined with HOBt) is used to carry out the reaction, no target amide is generated.

[0012] Therefore, in order to further improve the reactivity, the inventors use onium salt condensing agents (HATU, HBTU) to carry out the reaction, but a large amount of impurities with molecular weight of 99 more than that of intermediate 1 and intermediate 2 are found in the reaction product, which is speculated to be the impurities generated by the reaction of intermediate 1, intermediate 2 and onium salt condensing agent. Therefore, it can be seen that onium salt condensing agents are not suitable for this reaction.

[0013] .

[0014] Through further analysis of a large number of previous tests and theoretical basis, the inventors lock the condensing agent to carbodiimide, and after a large number of test screening, it is found that the use of EDC hydrochloride combined with activator HOAt, and the use of pyridine sulfonate or pyridine sulfonate as catalyst, has unexpected test results. The amidation catalyst is pyridine sulfonate, pyridine methane sulfonate, and pyridine p-toluenesulfonic acid salt. The above pyridine sulfonate is usually sodium or potassium salt, and the sulfonic acid group is substituted at position 2, 3 or 4 of pyridine. The yield of intermediate 2 can reach more than 80%, and the purity is greater than 90%. However, when EDC hydrochloride is combined with HOBt, no target product is generated.

[0015] .

[0016] The intermediate 2 is hydrolyzed by a base, and after acid treatment, the intermediate 3 is obtained, and the purity can be more than 95%. The intermediate 4 obtained by the reaction of the intermediate 3 and MAP is subjected to hydrogenation and deprotection to obtain the target product, etrapenem amide.

[0017] Since the reaction conditions of the intermediate 4 and the target product are mild, less impurities are generated, and therefore the purity of the etrapenem amide is mainly determined by the intermediates 2 and 3. The intermediate 2 prepared by the route in the present application has high purity, and the purity of the intermediate 3 obtained by the hydrolysis of the intermediate 2 by a base and the subsequent acid treatment is further improved. The purity of the final product, etrapenem amide, obtained by the preparation process in the present application can be more than 95%, which meets the quantitative and qualitative purity requirements in the research of drug impurities.

[0018] The etrapenem amide prepared by the present process is used as an impurity control sample to detect the etrapenem sodium lyophilized powder injection prepared by different processes by an external standard method, and the etrapenem amide is less than 0.1%. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 It is a high-resolution spectrum of etrapenem diisopropyl amide.

[0020] Fig. 2 It is a nuclear magnetic hydrogen spectrum of etrapenem diisopropyl amide.

[0021] The present application provides a method for preparing etrapenem amide, which has the advantages of simple operation and high product purity. The preparation of etrapenem amide lays a good foundation for the quality research and control of etrapenem. DETAILED EMBODIMENT

[0022] Example 1: 20 g of etrapenem side chain, 5.3 ml of isopropenyl acetate, and 6.7 ml of 30% perchloric acid are added to a three-necked flask, and stirred at 15-20°C for 4 hours. 660 ml of water is added, and stirred for crystallization for 1 hour. Filtration is performed, and the filter cake is slurried with 350 ml of water for 2 times, and then filtered. The filter cake is dried at 40°C to obtain 21.6 g of intermediate 1 dry product, with a yield of 98.7% and a purity of more than 99%.

[0023] Example 2: 21.6 g of the intermediate 1, 216 ml of dichloromethane, and 5.4 g of dimethylamine hydrochloride are added to a three-necked flask, and stirred and heated to 30°C. 11 ml of diisopropyl ethylamine is added, and stirred for 10 minutes. Then, 7.2 g of HOAt, 10.2 g of EDC.HCl, and 1.3 g of sodium 3-pyridine sulfonate are added, and stirred at 30-35°C for 3 hours. The solvent is evaporated under reduced pressure below 35°C, 150 ml of brine is added, and 120 ml of ethyl acetate is used for extraction for 3 times. The organic layers are combined, washed with 200 ml of water for 8 times, dried, and filtered. The filtrate is evaporated under reduced pressure below 40°C to obtain 18.8 g of the intermediate 2, with a yield of 82.5% and a purity of 91.8%.

[0024] Example 3: 18.8 g of intermediate 2 was added to 280 ml of methanol at -5 to -10 °C, 20 ml of 2N sodium hydroxide aqueous solution was added dropwise, after the dropwise addition was completed, the reaction was stirred at -5 to -10 °C for 5 hours, 1N hydrochloric acid was added to adjust the pH to 6-7, and the reaction was evaporated at 30 °C under reduced pressure, 250 ml of water was added, and 150 ml of ethyl acetate was extracted three times, the organic layer was washed with 200 ml of water once, and the organic layer was dried, filtered, and the filtrate was evaporated at 35 °C under reduced pressure to obtain 14.9 g of intermediate 3 with a yield of 86.3% and a purity of 96.7%.

[0025] Example 4: MAP 18.7 g and DMF 150 ml were added to a three-necked flask, cooled to -10 °C, and 14.9 g of intermediate 3 was added, cooled to -25 °C, and a mixture of 9.8 g of tetramethyl guanidine and 40 ml of DMF was added dropwise, and the reaction was carried out at -20 to -25 °C for 1.5 hours, and acetic acid was added to adjust the pH to 5-6, and the reaction solution was added to 500 ml of ice water, stirred for 0.5 hours, filtered, and the filter cake was added to 500 ml of ice water, stirred for 0.5 hours, filtered, and the wet product of intermediate 4 was obtained with a purity of 97.1%.

[0026] Example 5: The wet product of intermediate 4, 200 ml of purified water, 8.5 g of sodium bicarbonate, 260 ml of acetonitrile, and 25 g of 5% palladium on carbon (about 70% water) were added to an autoclave, and the reaction was carried out at 20 °C under a pressure of 1.2 MPa for 3 hours, the product was discharged, filtered, and the filter cake was washed with water, the filtrate was adjusted to pH 5-6 with acetic acid, 2000 ml of isopropyl alcohol at 0-5 °C was added, and the reaction was carried out at 0-5 °C for 12 hours, the product was filtered, 90 ml of water at 0-5 °C was added to the wet product, and the product was freeze-dried at 300 microbar at -40 °C to obtain 11.4 g of ertapenem amide (dimethylamine), and the total yield of the two steps from intermediate 3 to ertapenem amide was 71.9% with a purity of 96.8%.

[0027] Example 6: 20 g of ertapenem side chain, 5.3 ml of acetic anhydride, and 67 ml of pyridine were added to a three-necked flask, and the reaction was carried out at 15-20 °C for 4 hours, 660 ml of water was added, the reaction was carried out at 15-20 °C for 1 hour, the filter cake was slurried with 350 ml of water twice, filtered, and the filter cake was dried at 40 °C to obtain 21.2 g of dry intermediate 1 with a yield of 96.8% and a purity of >99%.

[0028] Example 7: Put 21.2 g of intermediate 1, 212 ml of dichloromethane, 6.6 g of diisopropylamine into a three-necked flask, stir, heat to 30°C, add 10.8 ml of diisopropyl ethylamine, stir for 10 minutes, then add HOAt 7.1 g, EDC hydrochloride 10.0 g, keep the temperature at 30-35°C, stir for 3 hours. Evaporate the solvent under reduced pressure below 35°C, add 150 ml of brine, extract 3 times with 120 ml of ethyl acetate, combine the organic layers, wash 8 times with 200 ml of water, dry the organic layer, filter, evaporate the filtrate under reduced pressure below 40°C, to obtain 20.0 g of intermediate 2, with a yield of 80.6% and a purity of 91.1%.

[0029] Example 8: Add 20.0 g of intermediate 2 to 300 ml of methanol at -5°C to -10°C, drop 19.3 ml of 2N sodium hydroxide aqueous solution, keep the temperature at -5°C to -10°C after the drop is completed, stir for 5 hours, adjust the pH to 6-7 with 1N hydrochloric acid, evaporate under reduced pressure at 30°C, add 265 ml of water, extract 3 times with 160 ml of ethyl acetate, combine the organic layers, wash once with 210 ml of water, dry the organic layer, filter, evaporate the filtrate under reduced pressure at 35°C, to obtain 15.5 g of intermediate 3, with a yield of 83.7% and a purity of 96.1%.

[0030] Example 9: Put MAP 17.4 g, DMF 140 ml into a three-necked flask, cool to -10°C, add 15.5 g of intermediate 3, cool to -25°C, drop the mixture of 9.1 g of tetramethyl guanidine and 37 ml of DMF, keep the temperature at -20°C to -25°C for 1.5 hours, adjust the pH to 5-6 with acetic acid, add the reaction solution to 465 ml of ice water, stir for 0.5 hours, filter, add the filter cake to 465 ml of ice water, stir for 0.5 hours, filter, to obtain intermediate 4 wet product with a purity of 96.6%.

[0031] Example 10: Put intermediate 4 wet product, 186 ml of purified water, 7.9 g of sodium bicarbonate, 242 ml of acetonitrile, 25.5 g of 5% palladium on carbon (about 70% water) into an autoclave, keep the temperature at 20°C, maintain the pressure at 1.2 MPa, hydrogenate for 3 hours, discharge, filter, wash the filter cake with water, adjust the pH of the filtrate to 5-6 with acetic acid, add 1860 ml of isopropyl alcohol at 0-5°C, keep the temperature at 0-5°C for 12 hours, filter, add 84 ml of water at 0-5°C to the wet product, freeze-dry at 300 μbar at -40°C, to obtain 10.4 g of ertapenemamide (diisopropylamine), with a total yield of 63.5% from intermediate 3 to ertapenemamide and a purity of 95.9%. The high resolution, hydrogen spectrum is shown as follows: Figs. 1-2 HRMS (ESI + ): [M+H] + = 559.2593, [M+Na] + = 581.2374;1 H NMR (600 MHz, DMSO): δ 1.07~1.16 (12H, m), 1.41 (6H, s), 1.62~1.66 (1H, m), 2.56~2.60 (1H, m), 2.66~2.69 (1H, m), 3.16-3.17 (2H, m), 3.34~3.37 (3H, m), 3.55~3.57 (1H, t), 3.82~3.85 (1H, t), 3.93~3.95 (1H, t), 4.11~4.13 (1H, m), 6.94~6.95 (1H, d), 7.32~7.35 (1H, m), 7.60~7.61 (1H, d), 7.68 (1H, s), 10.06 (1H, s).

[0032] Example 11: According to the preparation scheme of Example 1 in patent CN100384845C, the lyophilized powder injection containing sodium eravacnab, sodium bicarbonate and sodium hydroxide was prepared, and the HPLC condition for detecting the related substances in the national Food and Drug Administration standard for imported drugs (standard number: JX20080052) was used, and the external standard was prepared by using the eravacnab amide substance (dimethylamine) prepared by the process described in the patent, and the impurity content of eravacnab amide substance (dimethylamine) in the lyophilized powder injection was <0.1%.

[0033] Example 12: According to the preparation scheme of Example 8 in patent CN103127097B, the lyophilized powder injection containing sodium eravacnab with citric acid as the protective agent was prepared, and the HPLC condition for detecting the related substances in the national Food and Drug Administration standard for imported drugs (standard number: JX20080052) was used, and the external standard was prepared by using the eravacnab amide substance (dimethylamine) prepared by the process described in the patent, and the impurity content of eravacnab amide substance (dimethylamine) in the lyophilized powder injection was <0.1%.

Claims

1. A process for the preparation of a vitorabene amide characterized in that: The method comprises the following steps: (1) preparing an intermediate 1 by reacting the side chain of ertapenem with an acetylating agent and an acetylating catalyst; the acetylating agent is isopropenyl acetate, propenyl acetate or acetic anhydride; the acetylating catalyst is pyridine, acetyl chloride, 30%-60% perchloric acid or p-toluene sulfonic acid; The structure of the etanercept side chain is: ; (2) reacting the intermediate 1 with an amine or an amine salt in the presence of a condensing agent, an activating agent and a condensing catalyst to obtain an intermediate 2; the condensing catalyst is a pyridine sulfonic acid salt, a pyridine methane sulfonic acid salt or a pyridine p-toluene sulfonic acid salt; the condensing agent is EDC hydrochloride and the activating agent is HOAt; the amine or the amine salt is ethylamine, propylamine, isopropylamine, butylamine, dimethylamine, N-ethylmethylamine, diethylamine, dipropylamine, diisopropylamine or an amine salt thereof; (3) removing the acetyl group of the thiol group of the intermediate 2 by sodium hydroxide to obtain an intermediate 3; (4) reacting the intermediate 3 with MAP to obtain an intermediate 4; The structure of the MAP is: ; (5) hydrogenating and deprotecting the intermediate 4 to obtain ertapenem amide.

2. The method of preparing ertapenemamide according to claim 1, characterized in that: The solvent used in the reaction of step (2) is chlorinated hydrocarbon, nitrile, ketone, amide, sulfoxide or cyclic ether.

3. The method of preparing ertapenemamide according to claim 1, characterized in that: The reaction temperature in step (2) is 0-70℃.

4. The method of preparing ertapenemamide according to claim 3, characterized in that: The reaction temperature in step (2) is 15-40℃.

5. The method of preparing ertapenemamide according to claim 1, wherein: The solvent used in the reaction of step (3) is alcohol or nitrile.

6. The method of preparing ertapenemamide according to claim 1, wherein: The reaction temperature in step (3) is 0-40℃.

7. The method of preparing ertapenemamide according to claim 6, characterized in that: The reaction temperature in step (3) is -5-10℃.

Images