N- {1- 3- (2-ethoxy-5- (4-ethylpiperazinyl) sulfonylphenyl) -4,5-dihydro-5-oxo-1,2,4-triazin-6-yl ethyl} butyramide, its preparation method and its use

摘要

Disclosed are N-{1-[3-(2-ethoxy-5-(4-ethylpiperazinyl)sulfonylphenyl)-4,5-dihydro-5-oxo-1,2,4-triazin-6-yl]ethyl}butyramide (which is represented by formula III), its preparation method, intermediates during preparation procedure, preparation method for such intermediates and a method for preparing vardenafil from the compound. In the method for preparing vardenafil, a chloro-sulfonation reaction carries out in the early stage of the preparation procedure.