MASS-SPECTROMETRIC STUDIES OF TETRASUBSTITUTED YDRO-3H-1,2,4-TRIAZOLO[4,3-D][1,5]BENZOTHIAZEPINES

The mass spectrometric behaviour of seven tetrasubstituted hydro-3H-1, 2,4-triazolo[4,3d][1,5]benzothiazepines has been studied with the aid of mass-analysed ion kinetic energy spectrometry and exact mass measur ements 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[4,3b][1,3]benzothiazo le ions, and further undergo reverse 1,3-dipolar cycloadditions to giv e benzothiazole ions. The Formation of stable conjugated fused tetracy clic systems, substituted 1,2,4-triazolo[4,3-f]phenanthridine ions, un der electron impact ionization, has also been found. (C) 1998 John Wil ey & Sons, Ltd.