Acetic Anhydride → 4-Benzoylamino-1-hexyn-5-one

Participants

Reaction Conditions

Reaction Steps

Acetic anhydride (150 ml) was added to a solution of 2-benzoylamino-4-pentynoic acid (J. Org. Chem. 1983, 48, 3318) (73 g, 0.34 mol) in pyridine (200 ml) and the solution was heated to 90° C. for 1 hour, then allowed to cool to 60° C. and water (150 ml) was added. The mixture was heated to 85°-90° C. for 20 minutes, then cooled, diluted with water (300 ml) and extracted with chloroform (2×400 ml). The combined extracts were washed with water, 1N hydrochloric acid (3×500 ml), sodium bicarbonate and brine, and dried over magnesium sulfate. The chloroform solution was decolorized with charcoal, filtered and concentrated. The residue was recrystallized from butyl chloride to yield a tan solid (51 g, mp 101°-103° C.).

Provenance & Evidence