STRUCTURE DETERMINATION OF BUTLERIN-A, BUTLERIN-B AND BUTLERIN-C - 3 NEW LICHEN P-TERPHENYLS

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 ''-terpenyl]-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) Angstrom; Z 4. Refinement of 1049 data with I > 3 sigma(I) gave conventional R factors of 0.043 and 0.042.