Martin J. Kulig

Sterol metabolism. XXVI. Pyrolysis of some sterol allylic alcohols and hydroperoxides

Abstract The thermal decomposition of the allylic alcohols 5α-cholest-6-ene-3β,5-diol, cholest-5-ene-3β,7α-diol, and cholest-5-ene-3β,7β-diol and of the allylic hydroperoxides 3β-hydroxy-5α-cholest-6-ene-5-hydroperoxide, 3β-hydroxycho lest-5-ene-7α-hydroperoxide, and 3β-hydroxycholest-5ene-7β-hydroperoxide to six common major pyrolysis products cholest-5-ene-3β,7α-diol, cholest-5-ene-3β,7β-diol, 3β-hydroxycholest-5-en-7-one, cholesta-3,5-dien-7-one, cholesta-4,6-dien-3-one, and cholesta2,4,6-triene was established.

Sterol metabolism. XL. On the failure of superoxide radical anion to react with cholesterol

Superoxide radical anion (O-2) failed to react with cholesterol under a variety of conditions. In some instances products indicative of free radical oxidation by molecular oxygen (O2) were found, but no products of electronically excited (singlet) molecular oxygen (1O2) attack on cholesterol were detected. These results do not support a direct role of O-2 in lipid peroxidation of cholesterol-rich membranes or of the formation of 1O2 from O-2 dismutation.

Microbial hydroxylations—IX: On the dihydroxylation of 19-norsteroids by Curvularialunata

Abstract 10β-Hydroperoxy-17β-hydroxy-4-estren-3-one was transformed by vegetative cell cultures of Curvularialunata NRRL 2380 to 10β, 17β-dihydroxy-4-estren-3-one which was transformed in turn on prolonged fermentation to 10β-hydroxy-4-estrene-3,17-dione and 10β, 11β,17β-trihydroxy-4-estren-3-one. These results support sequential hydroxylation as the means by which 10β,11β,17β-trihydroxy-4-estren-3-one be formed from 17β-hydroxy-4-estren-3-one.

Sterol metabolism: XXXIII. On derivation of cholesterol 7-alkoxyl ethers

The facile acid-catalyzed conversion of cholest-5-ene-3β,7α-diol (but not of cholest-5-ene-3β, 7β-diol) in methanol or ethanol solution to the corresponding 7α-methyl or 7α-ethyl ethers and epimerization of the 7α-alkyl ethers to the corresponding 7β-alkyl ethers were established. The epimeric cholest-5-ene-3β, 7-diols, their 7-methyl ethers, and their 7-ethyl ethers are readily interconverted in acidified solvents, the quasiequatorial 7β-epimer predominating in each case. Both 7α- and 7β-alkyl ethers may be encountered as artifacts in analyses of sterol mixtures from mammalian tissues.