Oxepinochromenones, Furochromenone, and their Putative Precursors from the Endolichenic Fungus <i>Coniochaeta</i> sp.

Abstract

Six new polyketides including four oxepinochromenones, conioxepinols A−D (1−4), one furochromenone, coniofurol A (5), and one xanthone, conioxanthone A (6), have been isolated from the crude extract of the endolichenic fungus Coniochaeta sp. The absolute configurations of C-7 in 1 and the 7,8-diol moiety in 3 were assigned using the modified Mosher’s and Snatzke’s method, respectively, whereas that of C-8 in 5 was deduced via the circular dichroism data of the [Rh2(OCOCF3)4] complex. Compounds 2−4 showed modest cytotoxicity against a small panel of human tumor cell lines.