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Electron impact mass spectral fragmentation patterns of 2a,4‐disubstituted 5‐benzoyl‐2‐chloro‐2a,3,4,5‐tetrahydroazeto[1,2‐ a ][1,5]‐ benzodiazepin‐1(2 H )‐ones
Author(s) -
Xu Jiaxi,
Zuo Gang,
Jiao Peng,
Wang Hongzhong,
Jin Sheng,
Chan Albert S. C.
Publication year - 2000
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(20000430)14:8<633::aid-rcm920>3.0.co;2-z
Subject(s) - chemistry , ion , molecule , mass spectrometry , yield (engineering) , amide , electron ionization , fragmentation (computing) , medicinal chemistry , ionization , organic chemistry , chromatography , materials science , computer science , metallurgy , operating system
The mass spectrometric behaviour of six 2a,4‐disubstituted 5‐benzoyl‐2‐chloro‐2a,3,4,5‐tetrahydroazeto[1,2‐ a ][1,5]benzodiazepin‐1(2 H )‐ones has been studied with the aid of mass‐analysed ion kinetic energy spectrometry and accurate mass measurements under electron impact ionization. All compounds show a tendency to eliminate a chlorine atom, a chlorine atom plus benzaldehyde, benzoyl radical, chloroketene or chlorine atom plus CO and H 2 O molecules to yield, respectively, [M − Cl] + ions, 2a,4‐disubstituted 2a,3‐dihydroazeto[1,2‐ a ][1,5]benzodiazepin‐1(2 H )‐one ions, [M − PhCO] + ions, 2,4‐disubstituted 1‐benzoyl‐2,3‐dihydro‐1 H ‐1,5‐benzodiazepine ions, or 1,2,4‐trisubstituted 1 H ‐1,7‐benzodiazonine ions, which could also be formed from [M − Cl] + ions by loss of CO and H 2 O molecules simultaneously. The [M − Cl] + ions could further lose benzoyl radical to form [M − Cl − PhCO] + ions, or lose benzoyl amide and undergo a rearrangement to form 4,6‐disubstituted 1‐benzoazocine‐2(1 H )‐one ions. The [M − PhCO] + ions could eliminate NH to produce 2a,4‐disubstituted 2,2a,3,4‐tetrahydroazeto[1,2,‐ a ]quinolin‐1‐one ions, which could further eliminate chloroketene, CO and/or HCl to produce some important ions, respectively. 2,4‐Disubstituted 1‐benzoyl‐2,3‐dihydro‐1 H ‐1,5‐benzodiazepine ions could lose benzoyl radical to yield 2,4‐disubstituted 2,3‐dihydro‐1 H ‐1,5‐benzodiazepine ions, which could further yield other small fragment ions by loss of propene/styrene or small fragments. Copyright © 2000 John Wiley & Sons, Ltd.