The effect of intramolecular hydrogen bonding on the thermodynamics of partitioning of an isomer of the histamine H2-receptor antagonist metiamide.
The thermodynamics of transfer from water to 1-octanol of the 4 and 5 substituted N-methylimidazole isomers of the H2-receptor antagonist metiamide have been determined. The isomers have similar free energies of transfer but the enthalpy and entropy of transfer of the 4-isomer are substantially greater than those of the 5-isomer. This indicates that the 4-isomer forms an intramolecular hydrogen bond in the polar octanol phase.
D006860:Hydrogen Bonding; D007536:Isomerism; D008785:Metiamide / Q000031:analogs & derivatives*; D012995:Solubility; D012997:Solvents; D013816:Thermodynamics; D013890:Thiourea / Q000031:analogs & derivatives*
D012997:Solvents; D008785:Metiamide; D013890:Thiourea