C.M.R. spectra and conformational dynamics of oxygenated cis-10-Methyldecalins

Abstract

The thermodynamic parameters for equilibration of the chair-chair conformational enantiomorphs of cis-10-methyl-9-decalol (1) and (2) have been determined as E_A 69.8 ± 0.9 kJ mol^-1, ΔH? 66.7 ± 1.3 kJ mol^-1 and ΔS? + 12 ± 5 JK^-1 mol^-1. For cis-10-methyl-1-decalone, conformer (3) is 1.25 kJ mol^-1 more stable at 200 K than conformer (4) with E_A 42.9 ± 0.7 kJ mol^-1, ΔH? 41 .0 ± 0.7 kJ mol^-1 and ΔS? -20 ± 3J K^-1 mol^-1 for the conversion of (3) + (4. The c.m.r. spectra of these com- pounds, together with those for the coprostan-4-one and coprostan-6-one, have been assigned.