Sodium Dithionite → 4,5-Diamino-2-benzylpyrimid-6-one

Participants

Reaction Steps

A solution of sodium dithionite (62 g.) in water (300 ml.) was added dropwise during 30 minutes to a solution of 4-amino-2-benzyl-5-phenylazopyrimid-6-one (27 g.) in dimethylformamide (1000 ml.) at 75° C. The mixture was cooled, and the insoluble solid was filtered off. The filtrate was evaporated in vacuo, the residue was stirred with water, and the solid filtered off. This solid was extracted with boiling water (250 ml.), the extract was filtered hot and then cooled. The solid which separated was recrystallised from water to give 4,5-diamino-2-benzylpyrimid-6-one (12.4 g.) in the form of off-white needles, m.p. 243° C. (with decomposition).

Provenance & Evidence