2-Cyano-3-(2,3,6,7-tetra­hydro-1H,5H-benzo[ij]quinolizin-9-yl)prop-2-enoic acid dimethyl sulfoxide monosolvate

In dimethyl sulfoxide solvated 9-(2-carb­oxy-2-cyano­vin­yl)julolidine, C(16)H(16)N(2)O(2)·C(2)H(6)OS, the essentially planar –CH=(CN)–CO(2)H substituent (r.m.s. deviation = 0.014 Å) is almost coplanar with respect to the benzene ring, the dihedral angle between the two planes being 0.48 (2)°. The conformations of the fused, non-aromatic rings were found to be half-chair. In the crystal, the acid molecule forms a hydrogen bond to the O atom of the solvent mol­ecule. The acid mol­ecule is disordered over two positions with respect to the methyl­ene C atoms in a 1:1 ratio. The crystal studied was found to be a racemic twin.