Structure determination of new analogues of vardenafil and sildenafil in dietary supplements

H. J. Park, H. K. Jeong, M. I. Chang, M. H. Im, J. Y. Jeong, D. M. Choi, K. Park, M. K. Hong, J. Youm, S. B. Han, D. J. Kim, J. H. Park, S. W. Kwon

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


New analogues of vardenafil and sildenafil illegally added to dietary supplements were detected by high-performance liquid chromatography (HPLC) analysis with a photodiode array detector (PDA). These compounds were isolated and their structures elucidated by mass spectrometry (MS), infrared (IR) spectroscopy, one- and two-dimensional nuclear magnetic resonance (NMR). One of the new analogues given the trivial name pseudovardenafil (compound 1) was structurally elucidated and shown to be 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1-f][1,2,4] triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-piperidine. It was a vardenafil analogue isolated from a dietary supplement capsule Compared with vardenafil, the piperidine ring was substituted for the ethylpiperazine group. The second new analogue, trivially named hydroxyhongdenafil (compound 2), was separated from bulk powder used as a raw material for a dietary supplement. The piperazine and phenyl groups were connected through an acetyl group instead of a sulfonyl group, and hydroxyethylpiperazine was substituted for the methylpiperazine of sildenafil. It was structurally elucidated as 5-[2-ethoxy-5-[[4-(2-hydroxyethyl)-1-piperazinyl]acetyl]phenyl]-1, 4-dihydro-1-methyl-3-propyl-7H-pyrazolo[4,3-d]pyrimidin-7-one.

Original languageEnglish (US)
Pages (from-to)122-129
Number of pages8
JournalFood Additives and Contaminants
Issue number2
StatePublished - Feb 2007

ASJC Scopus subject areas

  • Food Science
  • Chemistry (miscellaneous)
  • Chemistry(all)
  • Toxicology
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis


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