Accela Chembio Co., Ltd.

Duoqing Xue

Yong Wu

Lianhua Zhai

Lihuang Chen

Yang Liu

Jun Yang

The present application provides a synthesis method for 1-methyl-1H-indazole-6-carboxylic acid. The synthesis method comprises: using 2-fluoro-4-bromobenzaldehyde and methylhydrazine as raw materials to obtain 6-bromo-1-methylindazole by means of an annulation reaction, and then performing a methyl formate reaction and a hydrolysis reaction, so as to obtain the 1-methyl-1H-indazole-6-carboxylic acid. The synthesis method provided in the present application can directly synthesize a 1-position methyl substituted indazole without isomers, thereby avoiding the problem that impurities are difficult to be removed in subsequent separation, thus improving the purity of a product. The yield of the annulation reaction can reach 85%.

Synthesis method for 1-methyl-1H-indazole-6-carboxylic acid

The present disclosure provides a method for preparing 2-ethyl-4-fluoro-1-nitrobenzene, including: (1) nitrifying 3-fluoroacetophenone with a nitration reagent, to obtain 1-(5-fluoro-2-nitrophenyl)ethanone; (2) reducing 1-(5-fluoro-2-nitrophenyl)ethanone with a reducing agent, to obtain 4-fluoro-2-(1-hydroxyethyl)-1-nitrobenzene; (3) iodinating 4-fluoro-2-(1-hydroxyethyl)-1-nitrobenzene, to obtain 4-fluoro-2-(1-iodoethyl)-1-nitrobenzene; and (4) reducing 4-fluoro-2-(1-iodoethyl)-1-nitrobenzene with a reducing agent, to obtain 2-ethyl-4-fluoro-1-nitrobenzene.

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Shanghai, China

Duoqing Xue