3-O-Methyl-1-isomangostin

IN THE TITLE XANTHONE DERIVATIVE [SYSTEMATIC NAME: 9-hy-droxy-5,10-dimeth-oxy-2,2-dimethyl-11-(3-methyl-but-2-en-1-yl)-2,3,4,12-tetra-hydro-1,7-dioxatetra-phen-12-one], C(25)H(28)O(6), the xanthone ring system is roughly planar, with an r.m.s. deviation of 0.1038 (1) Å. The chromane ring is in a half-chair conformation and the 3-methyl-but-2-enyl substituent is axially attached with an (+)-anti-clinal conformation. Two weak intra-molecular C-H⋯O inter-actions generate two S(6) ring motifs. In the crystal, mol-ecules are linked into ribbons along the c axis by O-H⋯O and weak C-H⋯O hydrogen bonds. A π-π inter-action, with a centroid-centroid distance of 3.5413 (8) Å, is also observed.