Mass spectrometric studies of cis- and trans-1a,3-disubstituted-1,1-dichloro-4-formyl-1a, 2,3,4-tetrahydro-1H-azirino [1,2-a] [1,5]benzodiazepines

The mass spectrometric behaviour of four cis- and trans-1a, 3-disuhsdtuted-1,1-dichloro-4-formyl-1a,2,3,4-tetrahydro-1H-azirino[1, 2-a] [1, 5]benzodiazepines has been studied with the aid of mass-analysed ion kinetic energy spectrometry and exact mass measurements under electron impact ionization. All compounds show a tendency to eliminate a chlorine atom from the aziridine ring, and then eliminate a neutral propene or styrene from the diazepine ring to yield azirino[1, 2b][1,3] benzimidazole ions. These azirino[1,2-a][1,5]benzodiazepines can also eliminate HCl, or Cl plus HCl simultaneously to undergo a ring enlargement rearrangement to yield 1,6-benzodiazocine ions, which further lose small molecular fragments, propyne or phenylacetylene, with rearrangement to give quinoxaline ions.Chemistry, MultidisciplinarySCI(E)3ARTICLE3368-3721