CRYSTAL AND MOLECULAR-STRUCTURE OF MEXOTICIN

5, 7-Dimethoxy-8-(3-methyl-2, 3-dihydroxybutyl)-2H-[1]-benzopyran-2-one (C16H20O6) crystallizes into orthorhombic space group P2(1)2(1)2(1) and has the following crystallographic parameters: a = 6.768(3), b = 9.872(1), c = 22.845(2) angstrom, mol. wt = 308, number of molecules per unit cell (Z) = 4, volume of the unit cell (V) = 1526.45 angstrom 3, radiation used C-mu-K-alpha-1 (lambda = 1.5405 angstrom), linear absorption coefficient (mu) = 8.2 cm-1, measured density (D(m)) = 1.349 gcm-3, observed density (D(x)) = 1.340 gcm-3, F(000) = 656, reliability index (R) = 0.056 and weighted R = factor(omega-R) = 0.060 for 1593 observed reflections. The lactone moietyis planar. Some bond distances in the lactone ring are of interest. Alternate molecules in the unit cell are reversed in orientation. The molecular pairs show some overlapping of the benzopyran part by the methoxy group.