Brucine salts of l ‐α‐hydroxy acids: brucinium hydrogen ( S )‐malate pentahydrate and anhydrous brucinium hydrogen (2 R ,3 R )‐tartrate at 130 K

The structures of two brucinium (2,3‐dimethoxy‐10‐oxostrychnidinium) salts of the α‐hydroxy acids l ‐malic acid and l ‐tartaric acid, namely brucinium hydrogen ( S )‐malate pentahydrate, C 23 H 27 N 2 O 4 + ·C 4 H 5 O 5 − ·5H 2 O, (I), and anhydrous brucinium hydrogen (2 R ,3 R )‐tartrate, C 23 H 27 N 2 O 4 + ·C 4 H 5 O 6 − ,(II), have been determined at 130 K. Compound (I) has two brucinium cations, two hydrogen malate anions and ten water molecules of solvation in the asymmetric unit, and forms an extensively hydrogen‐bonded three‐dimensional framework structure. In compound (II), the brucinium cations form the common undulating brucine sheet substructures, which accommodate parallel chains of head‐to‐tail hydrogen‐bonded tartrate anion species in the interstitial cavities.