Crystal structure of a photobiologically active furan-ocoumarin from Artemisia reticulata.

The title furan-ocoumarin, C14H12O4 [systematic name: 9-hy-droxy-2-(prop-1-en-2-yl)-2,3-di-hydro-7H-furo[3,2-g]chromen-7-one], crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. The two mol-ecules differ essentially in the orientation of the propenyl group with respect to the mean plane of the furan-ocoumarin moiety; the O-C(H)-C=C torsion angle is 122.2 (7)° in mol-ecule A and -10.8 (11)° in mol-ecule B. In the crystal, the A and B mol-ecules are linked via O-H⋯O hydrogen bonds, forming zigzag -A-B-A-B- chains propagating along [001]. The chains are reinforced by bifurcated C-H⋯(O,O) hydrogen bonds, forming ribbons which are linked via C-H⋯π and π-π inter-actions [inter-centroid distance = 3.602 (2) Å], forming a three-dimensional structure.