Optical rotatory dispersion and circular dichroism. Part LXXI. Low temperature circular dichroism of some tertiary carboxylic acids

Abstract

The c.d. of four series of tertiary carboxylic acids has been examined over the range –10 to –160°. The percentage changes in Δε are ca. 25% for diterpene-4β-carboxylic acids (axial) and for triterpene-17β-carboxylic acids of the oleanane and ursane series, ca. 16% for 17β-carboxylic acids of the lupene series, and very small for diterpene-4α-carboxylic acids (equatorial).