Phenolic Constituents of Grevillea robusta (Proteaceae). The Structure of Robustol, a Novel Macrocyclic Phenol

Abstract

Rutin, 2,5-dihydroxycinnamic acid (5), methyl 4-hydroxycinnamate (6), and a mixture of novel macrocyclic phenols have been isolated from the leaves of Grevillea robusta A. Cunn. The major macrocyclic phenol, robustol, has been shown to have the structure (8) by the application of physical methods and by degradation of robustol trimethyl ether (9) to give 3-[14?-(3?,5?-dimethoxyphenyl)tetradec-1?-yl]-5-methoxy-phenol (34). Three of the minor macrocyclic phenols have been assigned tentative structures (11), (12), and (13).