The Octant Rule VIII. Variable Temperature Circular Dichroism Spectra of α-Methyl- and Methoxyl-Substituted 5α-Cholestan-2- and -3-ones.

Article abstract of DOI:10.1016/0039-128X(80)90102-6

2α- and 2β-methyl- and methoxy-5α-cholestan-3-ones and 3α- and 3β-methyl- and methoxy-5α-cholestan-2-ones have been synthesized and their variable temperature circular dichroism spectra obtained and analyzed.Rotatory strength (R) values for α-axial and equatorial CH3 and OCH3 groups are determined by difference measurements with the parent ketone.The (small) equatorial CH3 R-values do not consistently follow the Octant Rule.Axial OCH3 groups do not obey the Octant Rule ("anti-octant" behavior) and impose a bathochromic shift on the C=O n-?* transition.Equatorial OCH3 groups do not consistently follow octant or "anti-octant" behavior.