Studies on the Components of Rhodea japonica Roth. IV

Structure of α- and β-Monoanhydrorhodexigenin A

Abstract

The structure of α- and β- anhydrorhodexigenin A was assumed to be as follows, from its absorption spectrum, coloration reaction and chemical behavior: β-anhydrorhodexigenin A possesses a double bond between C₁₄ and C₁₅, and its α-isomer is one of the following:
1) Unsaturated between C₁₅ and C₁₆;
2) Unsaturated between C₁₄ and C₁₅, with reverse steric configuration of C₈ from the β-isomer;
3) Unsaturated in C_5-6 or C_6-7 in the B ring.