Viagra: molecule of the week

Sildenafil, marketed as its citrate salt under the trade name Viagra, is the leading drug for treating erectile dysfunction. It was originally developed by Pfizer for treating pulmonary hypertension and angina pectoris. After scientists noticed that it produced penile erections, Pfizer patented it for this use in 1996 and received U.S. Food and Drug Administration approval for sale in 1998.

Chemical formula: C22 H30 N6 O4 S 

Name:1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl]-4-methylpiperazine citrate