Identification of a new sildenafil analogue adulterant, desethylcarbodenafil, in a herbal supplement.

In a maca-containing herbal supplement claimed to remedy erectile dysfunction, a new sildenafil analogue was found using adulterant screening with TLC, GC-MS and LC-MS/MS. This compound was isolated by column chromatography and HPLC, and identified by extensive 1D- and 2D-NMR and mass spectral analyses. The structure of this new compound was established as 5-[2-ethoxy-5-(piperazine-1-carbonyl) phenyl]-1-methyl-3-propyl-1,6-dihydro-pyrazolo[4,3-d]pyrimidin-7-one, and was named desethylcarbodenafil.