Methanesulfonic Acid → methyl 1H-indazole-3-carboxylate

Participants

Reaction Steps

A stirred mixture of indazole-3-carboxylic acid (5.00 g, 0.0309 mole), methanesulfonic acid (1 ml), and methanol (100 ml) was heated at reflux temperature for 5 hours and then concentrated to a volume of 30 ml and treated with excess saturated aqueous sodium bicarbonate solution. Water was added to give a volume of 200 ml and the suspended solid was collected by filtration. The wet solid was dissolved in methylene chloride (200 ml), and the solution separated from a small amount of water and some insoluble material. The methylene chloride solution was dried (magnesium sulfate) and concentrated to yield 3.25 g (60%) of indazole-3-carboxylic acid methyl ester.

Provenance & Evidence