title: Structural elucidation of impurities in 5-n-butyl-4-{4-[2-(1H-tetrazole-5-yl)-1H-pyrrol-1-yl]phenylmethyl}-2,4-dihydro-2-(2,6-dichlorophenyl)-3H-1,2,4-triazol-3-one (Ib), a novel nonpeptide angiotensin AT1 receptor antagonist.
abstract: 5-n-butyl-4-{4-[2-(1H-tetrazole-5-yl)-1H-pyrrol-1-yl]phenylmethyl}-2,4-dihydro-2-(2,6-dichlorophenyl)-3H-1,2,4-triazol-3-one (Ib), a new nonpeptide angiotensin AT1-receptor antagonist, has been observed to play a positive role in the treatment of hypertension in preclinical tests. Four process impurities of Ib were detected by LC-UV and LC/ESI-MS, and the impurities isolated by preparative HPLC chromatography were characterized by LC-MS/MS, high resolution MS (HRMS), NMR and IR analyses. The structures of impurities were confirmed as 5-n-butyl-4-{4-[2-chloro-5-(1H-tetrazole-5-yl)-1H-pyrrol-1-yl]phenylmethyl}-2,4-dihydro-2-(2,6-dichlorophenyl)-3H-1,2,4-triazol-3-one (I), 5-n-butyl-4-{4-[2-bromo-5-(1H-tetrazole-5-yl)-1H-pyrrol-1-yl]phenylmethyl}-2,4-dihydro-2-(2,6-dichlorophenyl)-3H-1,2,4-triazol-3-one (II), 5-n-butyl-4-{4-[4-chloro-2-(1H-tetrazole-5-yl)-1H-pyrrol-1-yl]phenylmethyl}-2,4-dihydro-2-(2,6-dichlorophenyl)-3H-1,2,4-triazol-3-one (III) and 5-n-butyl-4-{4-[4-bromo-2-(1H-tetrazole-5-yl)-1H-pyrrol-1-yl]phenylmethyl}-2,4-dihydro-2-(2,6-dichlorophenyl)-3H-1,2,4-triazol-3-one (IV), respectively. All of the four impurities were produced as the by-products of the bromination reaction by NBS (N-bromosuccinimide) in the synthesis of Ib.
authors.affiliation: Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Nanjing 210009, China. gaoting1736@126.com
authors.forename: Ting
authors.initials: T
authors.lastname: Gao
authors.forename: Yaxuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yibing
authors.initials: Y
authors.lastname: Ji
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Wu
authors.forename: Jinyi
authors.initials: J
authors.lastname: Xu
mesh_terms: D047228:Angiotensin II Type 1 Receptor Blockers / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods; D004340:Drug Contamination; D054879:Halogenation; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013777:Tetrazoles / Q000737:chemistry*; D014230:Triazoles / Q000737:chemistry*
chemical_list: C524079:5-n-butyl-4-(4-(2-(1H-tetrazol-5-yl)-1H-pyrrol-1-yl)phenylmethyl)-2,4-dihydro-2-(2,6-dichlorophenyl)-3H-1,2,4-triazol-3-one; D047228:Angiotensin II Type 1 Receptor Blockers; D013777:Tetrazoles; D014230:Triazoles