Crystal structure of 3-meth-oxy-carbonyl-2-(4-meth-oxy-phen-yl)-8-oxo-1-aza-spiro[4.5]deca-1,6,9-trien-1-ium-1-olate.

The title compound, C18H17NO5, was prepared by a synthetic strategy based on the Heck reaction from Morita-Baylis-Hillman adducts. The five-membered ring adopts a slightly twisted conformation on the Ca-Cm (a = aromatic and m = methyl-ene) bond. The dihedral angle between the five-membered ring and the spiro aromatic ring is 89.35 (7)°; that between the five-membered ring and the 4-meth-oxy-benzene ring is 4.65 (7)°. Two short intra-molecular C-H⋯O contacts occur. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds to generate a three-dimensional network.

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.

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.