2,3-Dimethoxy-10-oxostrychnidinium 2-carboxy-4,5-dichlorobenzoate

Abstract

The structure of the title compound, C23H27N2O4 +· C8H3Cl2O4 -, a 1:1 proton-transfer compound of brucine with 4,5-dichloro-phthalic acid, has been determined at 130 K. The brucinium cations and the hydrogen phthalate anions associate through single N - H⋯Ocarboxyl-ate hydrogen bonds [2.639 (3) Å], giving dimers which are extended via weak head-to-tail C - H⋯Ometh-oxy associations into chains forming down the 21 screw axis of the unit cell. The carboxyl proton of the anion gives a short intra-molecular O - H⋯Ocarbox-ylate hydrogen bond [2.441 (3) Å]. © International Union of Crystallography 2007.