Preparation method of 4-aminophenylacetic acid medicine intermediate

Abstract

The invention provides a preparation method of a 4-aminophenylacetic acid medicine intermediate. The preparation method comprises 1, adding concentrated sulfuric acid, concentrated nitric acid and benzyl cyanide into a reactor, carrying out a reaction process, and carrying out crystallization, filtration, water washing and re-crystallization to obtain 4-nitrophenylacetonitrile, 2, adding a sulfuric acid solution and glacial acetic acid into the 4-nitrophenylacetonitrile, carrying out heating backflow, after the reaction, pouring the reaction mixture into a reactor with ice water so that the product is crystallized and precipitated in the ice water, carrying out suction filtration to obtain white solids, carrying out re-crystallization through distilled water and glacial acetic acid, and drying the crystals to obtain 4-nitrophenylacetic acid, 3, adding 4-nitrophenylacetic acid, ethanol and skeletal nickel into a pressure reactor according to a certain ratio, carrying out a reaction process for some time, carrying out standing cooling to the room temperature, distilling to remove solvent ethanol, cooling the solution for crystallization, filtering the crystals and drying the crystals to obtain crude products, and 4, carrying out re-crystallization on the crude products through ethanol, and carrying out decoloring through active carbon to obtain light white crystals of 4-aminophenylacetic acid. The preparation method has a low cost and less side reactions and is suitable for industrial application.

Description

technical field [0001] The invention belongs to the technical field of pharmaceutical intermediates, in particular to a preparation method of p-aminophenylacetic acid pharmaceutical intermediates. Background technique [0002] Pharmaceutical intermediates are actually some chemical raw materials or chemical products used in the process of pharmaceutical synthesis. This kind of chemical product does not require a drug production license, and can be produced in ordinary chemical factories. As long as it reaches a certain level, it can be used in the synthesis of drugs. [0003] At present, my country needs more than 2,000 kinds of raw materials and intermediates for chemical industry every year, with a demand of more than 2.5 million tons. After more than 30 years of development, the chemical raw materials and intermediates required for my country's pharmaceutical production can basically be matched, and only a small part needs to be imported. And because our country is rela...

AI Technical Summary

Problems solved by technology

The existing methods for preparing p-aminophenylacetic acid all use p-nitrophenylacetic acid to obtain p-aminophenylacetic acid through catalytic reduction, yet, p-aminophenylacetic acid can be generated due to the further reaction of p-aminophenylacetic acid, and p-cyanophenylacetic acid is Pesticide intermediates, so the existing preparation method is easy to generate p-cyanophenylacetic acid; in addition, the existing preparation method, the selected catalyst needs higher temperature and pressure, high requirements for the reaction operating conditions, and the preparation cost of the catalyst is high, It is not conducive to cost reduction, and the conditions for catalytic reduction reaction are high, so it is not conducive to mass production