The nuclear magnetic resonance spectra and stereochemistry of 4-Benzoyloxy-1-thiaflavans

Abstract

The nuclear magnetic resonance spectra of cis- and trans-4-benzoyloxy- 1-thiaflavan in deuterochloroform have been investigated at 60 Mc/s. The spectral parameters for the heterocyclic ring protons have been obtained by analysis of the frequency-sweep double-resonance spectra and verified by an iterative technique using a digital computer. Long- range coupling constants were observed between the protons at C 4 and C 5 (J 0.8 c/s) and between the protons at C 2 and C 4 (J 0.2 c/s) for the cis isomer.