Preparation method of 3-chloro-4-fluoroaniline hydrochloride

Abstract

The invention provides a preparation method of 3-chloro-4-fluoroaniline hydrochloride. The 3-chloro-4-fluoroaniline hydrochloride is prepared from a raw material 3,4-dichloronitrobenzene through a three-step reaction comprising the steps of fluorine displacement, hydrogenation reduction and salt formation. The preparation method has the advantages of few byproducts, stable product properties, low reaction apparatus requirements because of the implementation of the nitro group reduction reaction using hydrogen and Pd-C at normal temperature, recycling of a solvent and Pd-C, and avoiding of the environmental pollution by introducing an excess HCl gas into an alkaline solution.

Description

technical field [0001] The invention relates to a preparation method of a pharmaceutical intermediate, in particular to a preparation method of 3-chloro-4-fluoroaniline hydrochloride. Background technique [0002] 3-Chloro-4-fluoroaniline is a very important starting material in the process of synthesizing the anticancer drug gefitinib, and is also an important intermediate in the synthesis of the antibacterial drug norfloxacin. In addition, 3-chloro-4-fluoroaniline is also an important intermediate in the synthesis of fluorine-containing pesticides, herbicides, plant growth regulators, and fungicides. The domestic production capacity of 3-chloro-4-fluoroaniline is about 1,000 tons, and the output is only a few hundred tons, and the product quality is not good enough to meet the needs of the domestic pharmaceutical industry in particular. Due to the small scale of domestic production enterprises, the product quality and output cannot meet the demand, especially the high-qua...

AI Technical Summary

Problems solved by technology

Among them, both method (2) and method (3) need to be chlorinated by chlorine gas, which is highly toxic and difficult to control the reaction conditions, and in method (3), expensive fluorobenzene is used as the raw material, the route cost is high, and the economic benefit is low

At present, the reduction of nitro groups in industrial production is still dominated by iron powder reduction. The post-treatment is troublesome, the total yield is low, and the consumption of raw materials is high. The resulting industrial wastewater is serious to environmental pollution.