Dalspinin, an isoflavone from Dalbergia spinosa roots

The X-ray crystal structure of the plant isoflavone dalspinin from Dalbergi a spinosa is determined. The compound, C17H12O7, is monoclinic in P2(1)/n w ith n = 3.970(1), b = 23.607(5), c = 14.633(3) Angstrom, beta = 94.46(3)deg rees, V = 1367.2(5) Angstrom(3), D-calc = 1.595 g cm(-1) and Z = 4. The mol ecular structure is characterized by a short intramolecular O-H ... O=C hyd rogen bond, and a large tilt angle of the two rigid ring systems with respe ct to each other. The intermolecular interactions in the crystal are discus sed.