Lithium Hydroxide → 1-Methyl-5-(1H-pyrrol-1-yl)-1H-pyrazole-4-carboxylic acid

Participants

Reaction Steps

To a solution of 1-methyl-5-pyrrol-1-yl-1H-pyrazole-4-carboxylic acid ethyl ester (20 g, 91.2 mmol; available from Butt Park Ltd., Camelford, Cornwall, UK) in methanol (100 mL) and water (100 mL) was added LiOH (2.4 g, 100 mmol). The reaction mixture was stirred at reflux for 4 hours and then concentrated under reduced pressure to remove the methanol. The residue was diluted with water, acidified to pH 2 with concentrated HCl (9 mL), and extracted with ethyl acetate. The combined extracts were evaporated in vacuo to give 1-methyl-5-pyrrol-1-yl-1H-pyrazole-4-carboxylic acid which was used without further purification.

Provenance & Evidence