Mass spectrometric studies of tetrasubstituted 3a,4,5,11-tetrahydro-3H-1,2,4-triazolo[4,3-d][1,5]benzothiazepines

Abstract

The mass spectrometric behaviour of seven tetrasubstituted 3a,4,5,11-tetrahydro-3H-1,2,4-triazolo[4,3-d][1,5]benzothiazepines 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 neutral substituted or unsubstituted styrene molecule from the thiazepine ring to yield 1,2,4-triazolo[4,3-b][1,3]benzothiazole ions, and further undergo reverse 1,3-dipolar cycloadditions to give benzothiazole ions. The formation of stable conjugated fused tetracyclic systems, substituted 1,2,4-triazolo[4,3-f]phenanthridine ions, under electron impact ionization, has also been found. © 1998 John Wiley & Sons, Ltd.