The synthesis of a phosphodiesterase(V) inhibitor Vardenafil

A selective phosphodiesterase(Ⅴ) inhibitor called Vardenafil was synthesized by using 2-ethoxybenzonitrile and DL-alanine as the raw materials.The two ring-closing reaction which is the decisive procedure of the whole synthesis was discussed and a new intermediate 4 was first separated.All the reaction conditions were optimized and all NMR spectrum data of the target molecule and intermediates are the same as those of reported.