Hydrochloric Acid → 6-(Benzyloxy)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To solution of oxalyl chloride (0.6 mL, 6.87 mmol) in anhydrous dichloromethane (15 mL), cooled at −78° C., was added, dropwise, a solution of anhydrous dimethyl sulfoxide (1.2 mL, 16.5 mmol) in dichloromethane (2 mL) and the resulting mixture was stirred for 10 minutes at −78° C. A solution of 2-benzyloxy-1,3-propanediol (0.5 g, 2.75 mmol) in dichloromethane (2 mL) was then added dropwise at −78° C. and the reaction mixture was stirred for 15 minutes. Triethylamine (4.6 mL, 33 mmol) was then added dropwise at −78° C. and the resulting mixture was stirred for 1 hour. The cold bath was removed and an aqueous solution of hydrochloric acid (6 M, 6 mL, 36 mmol) was added, followed by 5-amino-1H-pyrazole-4-carboxylic acid (0.35 g, 2.75 mmol) and the reaction mixture was heated at 70° C. for 1 hour. The solid formed was collected by filtration, washed with water and dried under vacuum. The solid residue (0.53 g) was then washed with dichloromethane to give 65 mg (9% yield) of 6-benzyloxy-pyrazolo[1,5-a]pyrimidine-3-carboxylic acid. MS=270 [M+H]+.

Provenance & Evidence