title: Crystal structure of methyl 2-(2H-1,3-benzodioxol-5-yl)-7,9-di-bromo-8-oxo-1-oxa-spiro-[4.5]deca-2,6,9-triene-3-car-boxyl-ate.
abstract: The title compound, C18H12Br2O6, was synthesized from Morita-Baylis-Hillman adducts. It incorporates the bromin-ated spiro-hexa-dienone moiety typically exhibited by compounds of this class that exhibit biological activity. Both the brominated cyclo-hexa-dienone and the central five-membered rings are nearly planar (r.m.s. deviations of 0.044 and 0.016 Å, respectively), being almost perpendicularly oriented [inter-planar angle = 89.47 (5)°]. With respect to the central five-membered ring, the brominated cyclo-hexa-dienone ring, the benzodioxol ring and the carboxyl-ate fragment make C-O-C-C, O-C-C-C and C-C-C-O dihedral angles of -122.11 (8), -27.20 (11) and -8.40 (12)°, respectively. An intra-molecular C-H⋯O hydrogen bond occurs. In the crystal, mol-ecules are linked by non-classical C-H⋯O and C-H⋯Br hydrogen bonds resulting in a molecular packing in which the brominated rings are in a head-to-head orientation, forming well marked planes parallel to the b axis.
authors.affiliation: Laboratory of Synthesis of Natural Products and Drugs, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Lucimara Julio
authors.initials: LJ
authors.lastname: Martins
authors.affiliation: Laboratory of Single Crystal X-Ray Diffraction, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Deborah de Alencar
authors.initials: Dde A
authors.lastname: Simoni
authors.affiliation: Laboratory of Structural Biology and Crystallography, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Aparicio
authors.affiliation: Laboratory of Synthesis of Natural Products and Drugs, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Coelho
keywords: Morita–Baylis–Hillman adducts; Single-crystal X-ray study; spiro-hexa­dienone structure