Regioselective Mono-bromination of Pyrrolo[2,1-f][1,2,4]triazin-4-amine

摘要

Pyrrolo[2,1-f][1,2,4]triazin-4-amine is regioselectively brominated when treated with 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione in different solvents. The brominated product, 5,7-dibromopyrrolo[2,1-f][1,2,4]triazin-4-amine predominates when the reaction is run in dichloromethane. The subsequent debromination process utilizes lithium-bromine exchange to give the desired product 5-bromo-pyrrolo[2,1-f][1,2,4]triazin-4-amine.