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

Abstract

The title compound, C18H12Br2O6, 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.

Methyl 8-oxo-2-phenyl-1-oxaspiro[4.5]deca-2,6,9-triene-3-carboxylate

“…The hexadienone ring is rotated by 89.79 (5) with respect to the five-membered ring. This is similar to the values found in related 5/6 spiro-ring fused systems containing the cyclohexadienone moiety that have been reported previously (Lou, 2012;Martins et al, 2014;Rønnest et al, 2011). The phenyl ring is inclined to the five-membered ring by 35.88 (6) , while the planar methyl carboxylate substituent, C3/C16/O4/C17, is inclined to this ring by only 6.61 (13) .…”

“…The phenyl ring is inclined to the five-membered ring by 35.88 (6) , while the planar methyl carboxylate substituent, C3/C16/O4/C17, is inclined to this ring by only 6.61 (13) . The torsion angles C4-C3-C16-O4, 5.93 (17) , C15-C1-C2-O2, data reports À141.12 (12) , and C1-C2-C3-C16, 4.3 (2) are close to those found in an analogous 5/6 spiro-system containing a dibrominated cyclohexadienone ring (Martins et al, 2014).…”