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(2H)-ones

✍ Scribed by Jiaxi Xu; Gang Zuo; Peng Jiao; Hongzhong Wang; Sheng Jin; Albert S. C. Chan

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 48 KB
• Volume: 14
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(20000430)14:8<633::aid-rcm920>3.0.co;2-z

✦ Synopsis

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(2H)-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 À Cl] ions, 2a,4-disubstituted 2a,3dihydroazeto[1,2-a][1,5]benzodiazepin-1(2H)-one ions, [M À PhCO] ions, 2,4-disubstituted 1-benzoyl-2,3dihydro-1H-1,5-benzodiazepine ions, or 1,2,4-trisubstituted 1H-1,7-benzodiazonine ions, which could also be formed from [M À Cl] ions by loss of CO and H 2 O molecules simultaneously. The [M À Cl] ions could further lose benzoyl radical to form [M À Cl À PhCO] ions, or lose benzoyl amide and undergo a rearrangement to form 4,6-disubstituted 1-benzoazocine-2(1H)-one ions. The [M À 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-1H-1,5-benzodiazepine ions could lose benzoyl radical to yield 2,4disubstituted 2,3-dihydro-1H-1,5-benzodiazepine ions, which could further yield other small fragment ions by loss of propene/styrene or small fragments.