Crystal structure of methyl 2-(2H-1,3-benzodioxol-5-yl)-7,9-di­bromo-8-oxo-1-oxa­spiro­[4.5]deca-2,6,9-triene-3-car­boxyl­ate

The title compound, C(18)H(12)Br(2)O(6), was synthesized from Morita–Baylis–Hillman adducts. It incorporates the bromin­ated spiro-hexa­dienone moiety typically exhibited by compounds of this class that exhibit biological activity. Both the brominated cyclo­hexa­dienone 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 [inter­planar angle = 89.47 (5)°]. With respect to the central five-membered ring, the brominated cyclo­hexa­dienone ring, the benzodioxol ring and the carboxyl­ate 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 intra­molecular C—H⋯O hydrogen bond occurs. In the crystal, mol­ecules 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.