Resolution of the chiral (1R,2S) enantiomer of cis-cyclohexane-1,2- dicarboxylic Acid in the brucinium salt 2,3-dimethoxy-10-oxostrychnidinium (1R,2S)-2-carboxycyclohexane-1-carboxylate dihydrate

摘要

The structure of the 1:1 brucinium salt of ciscyclohexane- 1,2-dicarboxylic acid, 2,3-dimethoxy-10-oxostrychnidinium (1R,2S)-2-carboxycyclohexane-1- carboxylate dihydrate, has revealed the resolved (1R,2S) enantiomer of the acid. Crystals of the compound are orthorhombic, space group P2 _12 _12 _1, with unit cell dimensions a = 8.1955(3), b = 12.4034(3), c = 29.9073(9) ?, and Z = 4. The asymmetric unit comprises the brucinium cation, the hydrogen cis-cyclohexane-1,2-dicarboxylate anion, in which the carboxylate group is disordered over two sites (58, 42%), and two water molecules of solvation, one of which is occupies two 50% occupancy sites. The classic undulating brucinium cation substructures are present with the anion and the water molecules occupying the interstitial cavities and are hydrogen- bonded to them in a two-dimensional network structure.