Hydrochloric Acid → 6-Methoxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid

Participants

Reaction Steps

To a solution of oxalyl chloride (6.9 mL) in dichloromethane (65 mL), cooled at −78° C., was added, dropwise, a solution of dimethyl sulfoxide (13 mL) in dichloromethane (16 mL) and the resulting mixture was stirred for 10 minutes. A solution of 2-O-methyl-glycerol (3.3 g, 31.5 mmol) in dichloromethane (16 mL) was then added dropwise and the reaction mixture was stirred for 15 minutes. Triethylamine (52 mL) was then added dropwise and the resulting mixture was stirred for 1 hour. The reaction mixture was warmed up to room temperature and an aqueous solution of hydrochloric acid (6 M, 35 mL) was added followed by 5-amino-1H-pyrazole-4-carboxylic acid (4 g, 31.5 mmol) and the resulting mixture was heated to 95° C. over 20 minutes, the temperature was maintained at 95° C. for 20 minutes. The resulting mixture was cooled to room temperature and stored at room temperature for 24 hours and at 4° C. for 62 hours. The solid formed was collected by filtration and dried in a vacuum oven to afford 1.087 g (18% yield) of 6-methoxy-pyrazolo[1,5-a]pyrimidine-3-carboxylic acid.

Provenance & Evidence