Sodium Hydroxide → 6-Bromo-3-[2,6-dimethoxy-4-(methoxymethyl)phenyl]pyrazolo[5,1-b][1,3]thiazole-7-carboxylic acid

Participants

Reaction Steps

To an ethanol (60.0 mL) solution of ethyl 6-bromo-3-[2,6-dimethoxy-4-(methoxymethyl)phenyl]pyrazolo[5,1-b][1,3]thiazole-7-carboxylate (3.84 g, 8.45 mmol) was added a 5N aqueous solution of sodium hydroxide (5.07 mL, 25.3 mmol) and heated to reflux for two hours. After the reaction was completed, the solvent was distilled off under reduced pressure, water (30 mL) was added to the residue, a 5N aqueous solution of hydrochloric acid was added while cooling on ice so that the solution became acidic, and the precipitated solid was subjected to suction filtration and dried to obtain the title compound (3.4 g, 7.96 mmol).

Provenance & Evidence