Synthesis of 2-Unsubstituted 1,3-Selenazoles by Cyclization of Selenoformamide with<i>α</i>-Bromocarbonyl Compounds
作者:Harald Below、Wolf-Diethard Pfeiffer、Karlheinz Geisler、Ashot S. Saghyan、Christine Fischer、Peter Langer
DOI:10.1002/jhet.2076
日期:2015.3
2‐Unsubstituted 1,3‐selenazoles were prepared by cyclization of selenoformamide with α‐bromoacetophenones. Parent 1,3‐selenazole was prepared by cyclization of selenoformamide with α‐bromoacetaldehyde.
2-Acyl-1,3-selenazoles were prepared in two steps from α-bromoketones and seleno amides. The base mediated fragmentation of these compounds afforded 2-unsubstituted 1,3-selenazoles. The reaction of 2-acyl-1,3-selenazoles with hydroxylamine hydrochloride afforded oximes which were transformed into 2-carbamoyl-1,3-selenazoles by a regioselective Beckmann rearrangement.