A process for preparation of 5-Ä2-ethoxy-5-(4-methylpiperazin-1-ylsulphonyl)phenylÜ-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazoloÄ4,3-dÜpyrimidin-7-oneÄsildenafilÜ

摘要

A process for the preparation of a compound of formula (I): CHEM also knows as sildenafil which comprises cyclisation of a compound of formula (II): CHEM