Environmental-friendly synthesis of oxazolines,imidazolines and thiazolines catalyzed by tungstophosphoric acid

摘要

A convenient and green method for the synthesis of aromatic 2-oxazolines,2-imidazolines and 2-thiazolines using tungstophosphoric acid(TPA),a commercially available,stable and reusable catalyst,from the reaction of aromatic nitriles and 2-aminoalcohols,ethylene-diamine or 2-aminoethanethiol under solvent-free conditions is reported.It is noteworthy that this procedure could be used for selective synthesis of mono-and bis-oxazolines and imidazolines from dicyanobenzene.In three cases the catalyst could be reused several times without significant loss of its catalytic activity.