1-(5-Hy-droxy-2,2,8,8-tetra-methyl-2H,8H-pyrano[2,3-f]chromen-6-yl)-3-(4-meth-oxy-phen-yl)prop-2-en-1-one.

In the biologically active title compound, C26H26O5, the pyran ring of the chromene unit adopts a half-chair conformation. The C=C double bond of the propenone unit exhibits a trans conformation and the carbonyl group is syn conformation to the double bond. The dihedral angle between the benzene ring and the benzopyran-one moiety is 31.54 (4)°. The mol-ecular structure is stabilized by an intra-molecular C=O⋯H-O hydrogen bond.