Hydrochloric Acid → 3-Benzyl-5,6,7,8-tetrahydroquinoxalin-2(1H)-one

Participants

Reaction Steps

A methanol (30 ml) solution of cyclohexane-1,2-dione (13.44 g, 0.12M) was added to phenylalanineamide hydrochloride (20.05 g, 0.1M) dissolved in methanol (200 ml) with cooling below -30° C., and aqueous 12.5N-NaOH (20 ml) was added dropwise thereto. The reaction mixture was stirred at below -30° C. for 30 minutes and was further stirred at room temperature for 3 hours. Conc. hydrochloric acid (25 ml) was added to the reaction mixture, and sodium bicarbonate (15 g) was added after 10 minutes stirring, the solvent then being distilled off in vacuo. The residue, to which was added water, was extracted three times with chloroform, and the extract was dried with anhydrous magnesium sulfate and concentrated in vacuo. The residue was recrystallized from acetone to obtain the product. (19.7 g, yield: 82.1%).

Provenance & Evidence