Direct conversion of 4-amino-2-phenyl-2-oxazolines into either 2-arylimino-1,3-oxazolidine or 2-arylimino-1,3-thiazolidine hydrochlorides

A novel heterocycle–heterocycle inter-conversion is reported. It enables direct and efficient syntheses of either polysubstituted 2-arylimino-1,3-oxazolidine or 2-arylimino-1,3-thiazolidine hydrochlorides by a one-pot treatment of 4-amino-2-phenyl-2-oxazolines with arylisocyanates or arylisothiocyanates, respectively, followed by addition of hydrochloric acid.