Preparation method of 5-amino-6-methyl benzimidazolone

Abstract

The invention relates to a preparation method of 5-amino-6-methyl benzimidazolone, belonging to the technical field of a compound preparation method, in particular to a preparation method of fine chemical intermediate. The preparation method is characterized by sequentially comprising the following steps of: carrying out condensation on 3, 4-diaminotoluene and urea, and preparing 5-methyl benzimidazolone; carrying out nitration reaction on the 5-methyl benzimidazolone under the condition of dilute nitric acid, and preparing 5-nitro-6-methyl benzimidazolone; and finally, carrying out reduction reaction on the 5-nitro-6-methyl benzimidazolone, and preparing the target compound of 5-amino-6-methyl benzimidazolone. In the reduction process of ferrous powder of the reduction reaction of the preparation method, alcohol-water system is taken as a solvent, and the system has low toxicity. In the process of hydrogenation reduction process, DMF-water system is taken as a solvent, and the solvent can be easily recovered, so that the cost is saved. In the process of hydrogenation reduction process, Nguyen Ni or Pd carbon is taken as a catalyst, so that the catalysis effect is good, the cost is low, and the synthetic route has simple technique.

Description

technical field [0001] The invention belongs to the technical field of compound preparation methods, and in particular relates to a preparation method of a fine chemical intermediate. Background technique [0002] 5-Amino-6-methylbenzimidazolone is a valuable fine chemical intermediate, which is not only used in the synthesis of various organic pigments, but also in the fields of dyes and medicines. Since the late 1980s, many companies such as Dominion Company in Canada, Klein Company in Germany, and Chibagaki Company in Switzerland have done in-depth and extensive research on the application field of this product, and have also made great achievements. With the development of the industry, many deep-processed products with excellent application performance have been obtained. But so far, there are few reports on the synthesis of 5-amino-6-methylbenzimidazolone. In our search of related documents including CA and Beil., we only found three articles about 5-amino-6 Reports ...

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Problems solved by technology

However, the patent does not report the quality of the obtained product, and the catalyst used for hydrogenation reduction in this process is self-made, and the patent does not clearly explain the manufacture of the catalyst

The third document is a patent applied by Cotico Co., Ltd. of Australia in China. The patent publication number is CN1675185. This patent adopts the three-step unit operation route of ring closure, nitration and reduction to realize the synthesis of the target product. From its report From the data point of view, the ring-closing yield is 56%, and the reduction reaction adopts palladium-carbon catalytic hydrogenation. This process has obtained a qualified target product, and the reduction yield is not reported. From the ring-closing yield, the cost of raw materials is relatively high. high