The Structure and Absolute Stereochemistry of Pisosterol, the Principal Triterpenoid From Fruitbodies of the Fungus Pisolithus tinctorius

Abstract

The structure and absolute stereochemistry of pisosterol [(22R,23S)-24-methyIene-5 α lanost - 8-ene-3β22,23-triol 22-acetate] (3), the principal colourless constituent of the mycorrhizal fungus Pisolithus tinctorius, are established by n.m.r. experiments and a single-crystal X-ray analysis of the (3,23-) diacetyl derivative (4).