Ammonia → 4,5-Dihydro-5-methyl-4-oxopyrano[3,2-b]indole-2-carboxamide

Participants

Reaction Steps

A suspension of 11.0 g (40.7 mmole) of ethyl 4,5-dihydro-5-methyl-4-oxopyrano[3,2-b]indole-2-carboxylate in 500 ml ethanol was stirred in ice while gaseous ammonia was added until the reaction mixture temperature reached 20° C. (ca. 10 min). The ice bath was removed, and stirring at room temperature was continued for a total of 24 hr. The light yellow solid was filtered and washed with a little cold ethanol. Recrystallization from 50% aqueous DMF gave light yellow needles of mp >295° C.

Provenance & Evidence