Thiophene → Ethyl 4-hydroxy-6-thienylcinnolin-3-yl carboxylate

Participants

Reaction Steps

Amyl nitrate (1 ml.) was added to a stirred suspension of ethyl 6-amino-4-hydroxycinnolin-3-yl carboxylate (1 g.) in thiophen (100 ml.). The suspension was stirred and heated under reflux for 2 hours. The suspension was filtered whilst hot and the filtrate was evaporated, giving a brown crystalline residue. The solid was applied to a silica column (100 g. of Kieselgel 60) and eluted with a 10% v/v mixture of dry ethanol and chloroform. The appropriate fractions were evaporated, and the residue was crystallised from 1:1 v/v aqueous ethanol to give ethyl 4-hydroxy-6-thienylcinnolin-3-yl carboxylate, m.p. 258°-260° C.

Provenance & Evidence