Taxine. Part III. A revised structure for the neutral fragment from O-cinnamoyltaxicin-I

Abstract

The neutral dialdehyde fragment, obtained by periodate cleavage of O-cinnamoyltaxicin-I, and formerly assigned the structure (II), has been re-investigated by means of an n.m.r. study of two of its derivatives, for which the structures (VI; R = R′= Ac) and (VII; R = CO·CH₂·CH₂Ph) are now deduced. This leads to the revised structure (V; R = CO·CH : CHPh) for the dialdehyde fragment; consequential alterations in the structures allotted to some of its degradation products are noted.