The stereochemistry of migrated hopanes epimeric at C-21

Abstract

The structures of four migrated hopanes, isolated from Sorghum bicolor and epimeric at C-21 and/or enantiomeric at the C-8, C-13, C-14, C-17, C-18, and C-21 positions: fernenol, 21-epifernenol (trematol), isoarborinol, and 21-epi-isoarborinol (sorghumol, a previously unidentified pentacycle), have been determined by analysing the chromatographic (g.l.c. and h.p.l.c.), spectral (mass and ¹H n.m.r.) and physical constant (m.p.) data of the naturally occurring (free) and chemically synthesized acetate and methyl ether derivatives.