Synthesis of 2-Formylpyrroles via Heterocyclic Interconversion

Significance

A heterocyclic interconversion of 5-substituted oxazoles into 2-formylpyrroles is reported. The aldol condensation products, resulting from treatment of ketones with 4-formyloxa­zoles, upon mesylation and mild base treatment, afford 2-formylpyrroles with alkyl, aryl, and alkenyl substituents. Furthermore, halogenated hetero­cycles may be incorporated which may allow further functionalization. This methodology was extended to the interconversion of a formylthiazole into an N-substituted 2-formylpyrrole.