Sildenafil citrate 2-METHYL-4-NITRO-2H-PYRAZOLE-3-CARBOXYLIC ACID (2-ethoxyphenyl)(4-methylpiperazin-1-yl)methanone Norneosildenafil Benzoic acid, 2-ethoxy-5-[(4-methyl-1-piperazinyl)sulfonyl]-, methyl ester 4-ethoxy-3-(1-methyl-7-oxo-3-propyl-4H-pyrazolo[4,3-d]pyrimidin-5-yl)benzenesulfonamide 4-Nitro-3-propyl-1H-pyrazole-5-carboxamide 1H-Pyrazole-3-carboxamide, 4-[(2-ethoxybenzoyl)amino]-5-propyl- 7H-Pyrazolo[4,3-d]pyrimidin-7-one, 5-[2-ethoxy-5-[[4-(hydroxymethyl)-1-piperazinyl]sulfonyl]phenyl]-1,6-dihydro-1-methyl-3-propyl- 5-[2-Ethoxy-5-[(4-Methyl-4-oxido-1-piperazinyl)sulfonyl]phenyl]-1,6-dihydro-1-Methyl-3-(2-Methylpropyl)-7H-pyrazolo[4,3-d]pyriMidin-7-one Desethyl Sildenafil 5-chloro-2-ethoxybenzoyl chloride 4-(2-Ethoxy benzamido)-1-methyl-3-n-propyl pyrazole-5-carboxamide. 1H-Pyrazole-5-carboxamide, 4-amino-3-propyl- 3-[6,7-Dihydro-1-methyl-3-(2-methylpropyl)-7-oxo-1H-pyrazolo[4,3-d]pyrimidin-5-yl]-4-ethoxybenzenesulfonyl Chloride Ethyl 2-ethoxy-5-((4-methylpiperazin-1-yl)sulfonyl)benzoate 5-chloro-2-ethoxybenzoic acid 4-nitro-5-propyl-1H-pyrazole-3-carboxylic acid