Structure Determination of Butlerin A, B and C—Three New Lichen p-Terphenyls

Abstract

The structures of butlerin A (1) (3′,4,4″,6′-tetramethoxy[1,1′:4′,1″-terphenyl]-2′-yl acetate), butlerin B (2) (3′,4,4″,5′-tetramethoxy[1,1′:4′,1″-terphenyl]-2′-yl acetate) and butlerin C (5) (3′,4,4″-trimethoxy[1,1′:4′,1″-terphenyl]-2′,6′-diyl acetate), three para-terphenyls from the lichen Relicina connivens, have been established by X-ray analysis of crystals of butlerins A and B and spectroscopic comparisons. Crystals of a mixture of butlerins A and B are orthorhombic, Pbcn, a 22.388(3), b 13.525(2), c 7.082(3) Ǻ; Z 4. Refinement of 1049 data with I > 3σ(I) gave conventional R factors of 0.043 and 0.042.