Lagoden dimethylformamide hemisolvate dihydrate: absolute configuration,dipolar interactions and hydrogen‐bonding interactions

Lagoden (L·3H₂O, where L is Na⁺·C₂₀H₃₃O₆⁻; sodium 3β,16,18‐trihydroxy‐8,13‐epi‐9,13‐epoxylabdan‐15‐oate trihydrate) is widely used as an effective haemostatic agent. It has been crystallized from dimethylformamide (DMF) as sodium 3β,16,18‐trihydroxy‐8,13‐epi‐9,13‐epoxylabdan‐15‐oate dimethylformamide hemisolvate dihydrate, Na⁺·C₂₀H₃₃O₆⁻·0.5C₃H₇NO·2H₂O or L₂·DMF·4H₂O, and the asymmetric unit contains two of the latter formulation. The four symmetry‐independent Na⁺ cations and lagoden anions, one DMF molecule and six of the eight symmetry‐independent water molecules assemble into a one‐dimensional polymeric structure via dipolar and hydrogen‐bonding interactions. The lagoden anions coordinate to the Na⁺ cations via the carboxylate groups and the two primary hydroxy groups, whereas the secondary OH groups are solely involved in hydrogen bonding. Two of the four symmetry‐independent lagoden anions act in a chelating mode, forming seven‐membered chelate rings. The absolute structure, based on anomalous dispersion data collected at 130 K with Cu Kα radiation, confirms an inverted configuration at chiral centres C8 and C13 (labdane numbering) relative to the labdane skeleton.