CRYSTAL AND MOLECULAR-STRUCTURE OF 6,7-BENZO-3,4 (1,4-DIMETHOXY-2,3-NAPHTHO)-1,5-DIOXOSUBERANE

The crystal and molecular structure of the title compound (2) C21H16O4 has been determined by an X-ray analysis, by direct methods from diff ractometer data and refined by full-matrix least squares. The compound (2) crystallizes in the space group P2(1)/a, with cell parameters: 36 .432(5), b = 5.512(3), c = 8.269(5) Angstrom, beta = 108.0(3)degrees, z = 4, D-c = 1.397 g/cm(-3), R = 7.8 for 1136 observed reflections. Th e conformation of the tetracyclic ring system shows a folding of two p lanar parts of the carbon skeleton about an axis passing thorough C8 a nd C16 of the seven membered ring C.