Synthetic method of 2-thiopheneacetic acid

Abstract

The invention relates to a synthetic method of 2-thiopheneacetic acid, and the synthetic method comprises the following steps: adding thiophene, methylbenzene and aluminium chloride anhydrous into a reaction container, dropping methyl chloroacetate while heating to 50-60 DEG C, and performing heat preservation after dropping; after cooling a reaction liquid to room temperature, pouring proper ice water and hydrochloric acid, layering, extracting the water layer by using proper methylbenzene, drying the organic layer by using anhydrous sodium sulphate, filtering, and concentrating a filtrate and alkaline liquor to be dry so as to obtain 2-thiophene methyl acetate; adding a sodium hydroxide aqueous solution and 2-thiophene methyl acetate into the reaction container, heating to 70-80 DEG C, performing heat preservation for 2-3 hours, cooling to room temperature after performing heat preservation, adjusting ph to 0.5 by using concentrated hydrochloric acid, cooling to 0-10 DEG C, performing heat preservation for 1-2 hours, filtering, and drying the filter cake to obtain 2-thiopheneacetic acid. The synthetic method of 2-thiopheneacetic acid disclosed by the invention has the advantages of being short in process route, cheap and easily available in raw materials, high in yield, good in product quality and suitable for large-scale production.

Description

technical field

[0001] The invention relates to a preparation method of a pharmaceutical intermediate 2-thiopheneacetic acid, belonging to the technical fields of medicine and chemical industry. Background technique

[0002] 2-thiopheneacetic acid is an important raw material for the preparation of 2-thiophene acetyl chloride, and is widely used in the pharmaceutical industry. Improve the antibacterial activity of the drug.

[0003] There are many synthetic methods reported for 2-thiopheneacetic acid, all of which use thiophene as a raw material and adopt a multi-step synthesis process to finally obtain the product. But the most important are the following methods:

[0004] 1. Using thiophene as a raw material, acetylate it under a catalyst to obtain 2-acetylthiophene, then react with ethanol, sulfur, and ammonia water under pressure to obtain 2-thiopheneacetamide, and then hydrolyze to obtain 2-thiopheneacetic acid. The process of preparing 2-thiopheneacetamide from 2-ac...