Benzaldehyde → 3-Phenylpyrazin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 0.3 mol. of potassium cyanide and 0.3 mol. of ammonium chloride in 100 ml. of water is added a solution of 0.3 mol. of benzaldehyde (Aldrich Chemical Co.) in 100 ml. of methanol. The reaction mixture is stirred at 25° C. for 6.0 hr. The oil layer is isolated and dissolved in methylene chloride. The solution is washed with water, dried and evaporated to give a brown oil. The oil is stirred with 150 ml. of concentrated hydrochloric acid for 1.0 hr. at 45° C. to precipitate phenylglycinamide hydrochloride. The precipitate is dissolved in 120 ml. of water stirred and cooled to 2° C. A solution of 4.8 g. (0.03 mol.) of 40% aqueous glyoxal is added, followed by dropwise addition of 6.0 ml. of 10 N sodium hydroxide. The reaction mixture is stirred for 5.0 hr. at 2° C. and then filtered. The filtrate is acidified to pH 6 with 3.0 ml. of 10 N hydrochloric acid and the precipitate of title compound is collected by filtration.

Provenance & Evidence