Methanol → methyl 1H-indazole-3-carboxylate

Participants

Reaction Steps

0.5 ml of concentrated sulphuric acid (95%) is added dropwise, at a temperature in the region of 20° C., to a solution of 9.13 g of 3-indazolecarboxylic acid in 100 ml of methanol. After refluxing for 20 hours, the reaction medium is concentrated under reduced pressure at a temperature in the region of 40° C. The aqueous residue obtained is extracted with dichloromethane. The organic phases are combined, washed with water until neutral, dried over magnesium sulphate and then concentrated under reduced pressure at a temperature in the region of 40° C. The yellow powder obtained is washed with ethyl ether. A white powder is obtained. The filtrate is concentrated under reduced pressure until a yellow powder is obtained. This yellow powder is washed again with ethyl ether until a white powder is obtained. The yellow filtrate is concentrated a third time under reduced pressure and the yellow powder collected is itself also washed with ethyl ether. All the fractions of white powder are combined. 7.08 g of methyl 3-indazolecarboxylate are thus obtained in the form of a white powder.

Provenance & Evidence