NMR spectra and conformational analysis of some 4,5-dihydro-s-triazolo[3,4-d][1,5]benzothiazepine derivatives

High field ¹H and ¹³C nmr spectra of a series of 1-substituted-4,5-dihydro-s-triazolo[3,4-d][1,5]benzothiazepine derivatives have been recorded. These have shown that, unless X = H or O, the molecules occur as a mixture of two slowly interconverting conformers at ambient temperatures. Variable temperature nmr experiments disclosed that the energy barrier to interconversion varies with the size of the substituent X located at position 1 of the fused s-triazole ring.