title: Isolation and identification of thiohomosildenafil and thiosildenafil in health supplements.
abstract: Two unknown compounds are detected and isolated from health supplements for the enhancement of sexual function. The structures of the unknown compounds are elucidated using high-resolution MS, ESI-MS/MS, NMR, UV and IR. One compound is identified as an analogue of sildenafil in which the oxygen atom is substituted with a sulfur atom in the pyrazolopyrimidine moiety, and an ethyl group instead of a methyl group is attached to the piperazinyl nitrogen. Hence, this compound is named thiohomosildenafil. Another compound is also a sildenafil analogue in which the oxygen atom is substituted with a sulfur atom in the pyrazolopyrimidine moiety. This compound is named thiosildenafil. Both the two compounds are first detected in health supplements. The UV, IR and completely assigned NMR data of thiohomosildenafil and thiosildenafil are first reported.
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
authors.forename: Peng
authors.initials: P
authors.lastname: Zou
authors.forename: Peiling
authors.initials: P
authors.lastname: Hou
authors.forename: Sharon Sze-Yin
authors.initials: SS
authors.lastname: Oh
authors.forename: Y M
authors.initials: YM
authors.lastname: Chong
authors.forename: Bosco Chen
authors.initials: BC
authors.lastname: Bloodworth
authors.forename: Min-Yong
authors.initials: MY
authors.lastname: Low
authors.forename: Hwee-Ling
authors.initials: HL
authors.lastname: Koh
mesh_terms: D019587:Dietary Supplements / Q000032:analysis*; D005506:Food Contamination; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D015394:Molecular Structure; D010726:Phosphodiesterase Inhibitors / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D010879:Piperazines / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D011687:Purines / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D000068677:Sildenafil Citrate; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013450:Sulfones / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D053719:Tandem Mass Spectrometry
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate