PROCESS FOR PREPARATION OF 1-ETHYL-4-{3-3-ETHYL-6, 7-DIHYDRO-7-OXO-2-(PYRIDYLMETHYL)-2H-PYRAZOLO 4,3-d PYRIMIDIN-5-YL-4-PROPOXYSULFONYL}-PIPERAZINE AND THE 4-2-SUBSTITUTED-5-(4-ETHYL-1-PIPERAZINYLSUPHONYL)-BENZAMIDO-5-ETHYL-1-(2-PYRIDYLMETHYL)1H-PYRAZOLE-3-CARBOXAMIDE INTERMEDIATES THEREFOR

摘要

A process is provided for the preparation of a compound of formulae (IA) (sidenafil/ ViagraTm TM ) and (IB) CHEM comprising reacting a compound of formula (IIA) and (IIB) respectively in the presence of -OR, wherein R in the case of formation of compound (IA) is CH2CH3 and R in the case of formation of compound (IB) is CH2CH2CH3, where X is a leaving group: CHEM