Method for converting furan ammonium salt cis-trans isomer

Abstract

The invention belongs to the technical field of medical intermediate preparation, and specifically relates to a method for converting a furan ammonium salt cis-trans isomer. The method comprises the following steps: dissolving a furan trans isomer (E)-SMIA in an organic solvent, then performing an isomerization reaction with a catalyst in the organic solvent to convert the (E)-SMIA into a cis isomer of furan ammonium salt (Z)-SMIA. In an implementation process of the technology provided by the invention, the catalyst can be recycled; experiments prove that after the catalyst is recycled for 101 times, the product conversion rate is not reduced, and any change of the catalyst structure is not observed; the operation process is simple, no additives are added during the conversion, the generation of other three wastes is avoided, and the production technology is green and environmentally friendly.

Description

Technical field [0001] The invention belongs to the technical field of preparation of pharmaceutical intermediates, and specifically relates to a method for transforming cis-trans isomers of furan ammonium salt. Background technique [0002] Furan ammonium salt (chemical name: (Z)-2-methoxyimino-2-(furan-2-yl) ammonium acetate) is an important intermediate of the cephalosporin antibiotic cefuroxime. It is used in the preparation of existing furan ammonium salts. During the process, about 10%-15% of the by-product of trans isomer—(E)-2-methoxyimino-2-(furan-2-yl)acetic acid ammonia is formed, and during the purification process, A small amount of furan ammonium salt product—(Z)-2-methoxyimino-2-(furan-2-yl)ammonium acetate is mixed into the trans-isomer by-products, forming a brown-black waste liquid. The generation of the waste liquid not only reduces the yield of the furan ammonium salt product, but more serious is the environmental protection problem that it has a large smell ...

AI Technical Summary

Problems solved by technology

The obtained furanone acid is further reacted with methoxyammonium salt etc. to obtain the furan ammonium salt product; although this method can finally obtain the furan ammonium salt product from the furan ammonium salt waste residue, there are following defects: first, the photochemical reactor At present, it can only be used as an experimental teaching instrument. The maximum volume that can be manufactured is only 5 liters. The volume is too small. Due to the difficulty in the protection of ultraviolet rays, it has not yet been industrialized; secondly, the trans product is heated in the process of concentrating the mother liquor. , leading to an increase in trans isomers, which contradicts the original intention of reducing trans isomer products, increases the difficulty of separation, and also causes a waste of energy

However, the invention still has the following defects: firstly, the primary conversion rate is low, and the conversion rate is only 59%-72%, which leads to increased difficulty in the separation of the product and the raw material, and complicated post-treatment processes; the second is the trans isomer content of the obtained product High quality, poor quality, not up to the quality standard requirements of furan ammonium salt products; third, the catalyst used is a Lewis acid metal salt, and metal ions exist in the form of "naked" ions in the reaction system, which are easily mixed into furan ammonium salt products , causing the heavy metal content in the product to exceed the standard

During the production process of this part of the trans by-product, the current treatment method is to divide it into the dichlorine waste residue, which has a strong smell and seriously pollutes the environment.

Images