SOLID-PHASE SYNTHESIS OF 3,4-DIHYDROQUINAZOLINE

A novel, facile and efficient method for the synthesis of aryl iminoph osphorane has been developed by treating a series of Ar-NH2 (1) attach ed to a solid support with Ph3P and diethyl azodicarboxylate at room t emperature. The resulting solid-supported cinnamyl iminophosphorane (4 ) was treated with an aryl isocyanate to generate the corresponding so lid-supported carbodiimide (5), which upon exposure to a secondary ami ne underwent 1,2-addition followed by an intramolecular Michael additi on to afford the desired 3,4-dihydroquinazoline (7). (C) 1997 Elsevier Science Ltd.