	US 12,258,318 B2
	Synthesis method for 1-methyl-1H-indazole-6-carboxylic acid
Jun Yang, Shanghai (CN); Duoqing Xue, Shanghai (CN); Yong Wu, Shanghai (CN); Lihuang Chen, Shanghai (CN); and Lianhua Zhai, Shanghai (CN)
Assigned to ACCELA CHEMBIO CO., LTD., Shanghai (CN)
Appl. No. 17/614,473
Filed by ACCELA CHEMBIO CO., LTD., Shanghai (CN)
PCT Filed Jun. 3, 2020, PCT No. PCT/CN2020/094153 § 371(c)(1), (2) Date Nov. 26, 2021, PCT Pub. No. WO2020/253533, PCT Pub. Date Dec. 24, 2020.
Claims priority of application No. 201910522457.1 (CN), filed on Jun. 17, 2019.
Prior Publication US 2022/0235010 A1, Jul. 28, 2022
Int. Cl. C07D 231/56 (2006.01)

CPC C07D 231/56 (2013.01)

13 Claims

1. A synthesis method for 1-methyl-1H-indazole-6-carboxylic acid, comprising:

subjecting 2-fluoro-4-bromobenzaldehyde and methylhydrazine as raw materials to an annulation reaction to obtain 6-bromo-1-methylindazole;

dissolving the 6-bromo-1-methylindazole in methanol and performing a reaction under a carbon monoxide atmosphere in the presence of a first base and a catalyst to obtain methyl 1-methyl-1H-indazole-6-carboxylate; and

subjecting the methyl 1-methyl-1H-indazole-6-carboxylate to a hydrolysis reaction to obtain the 1-methyl-1H-indazole-6-carboxylic acid;

wherein in the annulation reaction a solvent is used, and the solvent is N,N-dimethylacetamide.