N-{1-[3-(2-ethoxy-5-(4-ethylpiperazinyl)sulfonylphenyl)-4,5-dihydro-5-OXO-1,2,4-triazin-6-yl]ethyl}butyramide, the preparation method and use thereof

Abstract

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 and utilized for preparing vardenafil), 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

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