Structure of Lanostenol

Abstract

RECENTLY, the molecular structure of lanostadienol (lanosterol), C₃₀H₅₀O, an important ‘triterpenoid’ constituent of wool-wax, has been studied intensively. Ruzicka et al.¹ and Barton, McGhie et al.² have suggested three possible formulæ and, considering the evidence available, were unable to decide between them. Earlier, We had begun an X-ray structure analysis to provide unequivocal proof of the molecular structure of lanostadienol. This investigation has provided, in addition, a complete description of the stereochemistry of the molecule, avoiding the complex orthodox methods of stereochemistry. From earlier Work, lanostadienol is known to contain four rings, one inert double-bond and one active double bond in the terminal isopropylidene group of the long side-chain. Hydrogenation of the active double-bond yields lanostenol, and the iodoacetate of this compound³ was selected as a suitable ‘heavy-atom’ derivative for the structure analysis.