NMR Spectral Studies of Some Six–membered and Seven–membered Saturated Hetero Cyclic Compounds-calculation of Torsional Angles from Vicinal Coupling Constants–using Altona’s Equation

Abstract

Some six and seven membered saturated hetero cyclic compounds were prepared; then, from their vicinal coupling constants, proton – proton Torsional angles were calculated using Altona’s Equation. 1 H NMR spectra were recorded in DMSO – d 6 . The chemical shifts were compared with those in CDCl 3 . The COSY, NOESY and 13 C- 1 H correlation spectra had been recorded to assign the signals unambiguously. Then, torsional angles were calculated using electronegativity values of the substituents; the electronegativity value of oxygen was taken to be 3.50.Calculations were made accurately.