STRUCTURE OF HEXAMETHYLHEXAHYDROPYRNOPETROCARPAN

Abstract

1,2,7a,10,11,14a-Hexahydro-3,3,7,7,9,9-hexamethyl-3H,7H,9H-[1]benzopyrano[8',7':4,5]furo[3,2-c]pyrano[3,2-g][1]benzopyran, C27H32O4, m.p. 422-423 K, M(r) = 420.55, monoclinic, P2(1)/c, a = 9.984 (2), b = 17.632 (1), c = 13.223 (1) angstrom, beta = 100.57 (1)-degrees, V = 2288.25 (4) angstrom-3, Z = 4, D(x) = 1.220, D(m) = 1.235 Mg m-3 (by flotation in CCl4/C4H8O2), lambda(Cu K-alpha) = 1.5418 angstrom, mu = 0.56 mm-1, F(000) = 904, T = 296 K, final R, wR 0.0401, 0.0506, respectively, for 2665 observed reflections. The benzofurobenzopyran (C/D) ring junction is cis and the conformation is staggered looking from C(7) to C(7a). Three atoms in ring F occupy two positions each with s.o.f.'s 0.7 and 0.3. The dihedral angle between the aromatic rings [37.3 (2)-degrees] is close to that reported for analogous antifungal-active natural products.