Synthetic Studies of the Flavone Derivatives. VII. The Synthesis of Jaceidin

Abstract

The Hoesch reaction of iretol with methoxyacetonitrile yielded 2,4,6-trihydroxy-3,ω-dimethoxyacetophenone. According to the Allan-Robinson flavone synthesis with O-benzylvanillic anhydride, the acetophenone afforded 4′-benzyloxy-5,7-dihydroxy-3,3′,6-trimethoxyflavone. The catalytic debenzylation of the flavone gave jaceidin, 4′,5,7-trihydroxy-3,3′,6-trimethoxyflavone, which had previously been isolated from Centaurea species. Its triethyl ether was prepared from 3,5-diethoxy-4-methoxyphenol via the corresponding acetophenone, followed by the abovementioned flavone synthesis with O-ethylvanillic anhydride. The ultraviolet spectra of these flavones will also be reported.