Hydrochloric Acid → Zaleplon

Participants

Reaction Steps

N-[3-[3-(dimethylamino)-1-oxo-2-propenyl]phenyl]-N-ethylacetamide (2.6 g, 0.01 mol) and 3-amino-4-cyanopyrazole (1.08 g, 0.01 mol) were dissolved in the mixture of water (35 cm3) and methanol (20 cm3). Concentrated (37%) hydrochloride acid (1.0 cm3, 0.012 mol) was then added and the mixture was stirred at room temperature for about 2 hours. The reaction mixture was then cooled to about 5° C. and the crystalline product that formed was collected, washed with water and dried at about 60° C. to yield zaleplon (2.80 g, 91.8%) in 98.69% purity as determined by HPLC.

Provenance & Evidence