Biosynthesis of terpenes and steroids. Part V. The synthesis of ergosta-5,7,22,24(28)-tetraen-3β-ol, a biosynthetic precursor of ergosterol

Abstract

The Diels–Alder adduct between ergosterol and 4-phenyl-1,2,4-triazolin-3,5-dione is reconverted into ergosterol in high yield by reduction with lithium aluminium hydride. The adduct has been used in a synthesis of ergosta-5,7,22,24(28)-tetraen-3β-ol. An analogous synthesis of ergosta-5,7,22,24(28)-tetraen-3β-ol using radioactive intermediates enabled the intermediacy of this compound in ergosterol biosynthesis in yeast to be demonstrated.