Structure elucidation of a novel synthetic thiono analogue of sildenafil detected in an alleged herbal aphrodisiac

A new analogue of sildenafil was detected in a herbal aphrodisiac. The structure of the compound was established using LC-MS, UV and IR spectroscopy, MS-MS, and NMR. The compound, named thio-homosildenafil is a synthetic N-ethylpiperazine analogue of sildenafil in which also the C=O moiety has been converted into a C=S group. This is the first time a sildenafil analogue modified at the chromophore was identified as an adulterant of a herbal aphrodisiac. Preliminary pharmacological analysis confirmed the erectogenic potency of thio-homosildenafil. (C) 2007 Elsevier B.V. All rights reserved.