Method for preparing metronidazole benzoate

Abstract

The invention discloses a method for preparing metronidazole benzoate. The method comprises the following steps of: (1) dissolving metronidazole in a solvent, adding benzoyl chloride and performing esterification reaction at the temperature of 500 to 700 DEG C, wherein the solvent is selected from tributylamine, a tributylamine and toluene binary system compound, a tributylamine and acetone binary system compound and a tributylamine, toluene and acetone ternary system compound; (2) adding cooled unsalted water into an esterification reaction product to completely dissolve a solid, cooling an organic phase, and recrystallizing to obtain a crude metronidazole benzoate; and (3) putting the crude metronidazole benzoate into an ethanol solvent for dissolving, adding activated carbon, decoloring, filtering, cooling, recrystallizing, filtering, washing and drying to obtain a finished metronidazole benzoate. By the method, the metronidazole benzoate with high yield, high environment-friendly performance and high product quality is prepared.

Description

technical field [0001] The invention relates to a preparation method of benzoyl metronidazole, in particular to a method for preparing benzoyl metronidazole by using tributylamine or a multi-system mixture thereof as a reaction solvent. Background technique [0002] The chemical name of benzoyl metronidazole is 1-(2-benzoyloxyethyl)-2-methyl-5-nitroimidazole, which has the following structure: Benzoyl metronidazole is an anti-trichomonas and anti-infection drug. Specifically, it can be used for trichomoniasis of the genitourinary system, such as vaginal trichomoniasis, etc.; intestinal and parenteral amoebiasis, such as amoebiasis and amebic liver abscess; giardiasis; sensitive anaerobic bacteria Various infections caused by it, such as bacteremia, septicemia, infection after abdominal operation, etc.; prevention of gynecological and postoperative infection caused by anaerobic bacteria. In summary, benzoyl metronidazole has great medical value and good profit prospec...

AI Technical Summary

Problems solved by technology

(1) The molar yield of benzoyl metronidazole produced by using the existing technology is low, only 86%, resulting in high production costs

(2) The impurities in the products of benzoyl metronidazole produced by the existing technology are relatively high, exceeding 0.25%, which affects the quality of the products

(3) In the prior art, pyridine is used as an acid-binding agent, which produces an unpleasant stench during production, and the production environment is harsh, so it is not suitable for large-scale production

(4) Pyridine has extremely strong biological toxicity, which will affect the health of employees during the production process and cause huge pollution to the environment