Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Effect of the H/D solvent isotope substitution on enthalpy-related interaction parameters in aqueous solutions of the racemic Albicar at T = 298.15 K and ambient pressure

Ivanov, E. V.[Evgeniy V.], Batov, D. V.[Dmitriy V.]
J. Chem. Thermodyn. 2016, 102, 9-11
ABSTRACT
Previously [JCT: 97 (2016) 341 347], we have discussed the temperature-dependent enthalpies of dissolution of a chiral drug Albicar or 1,4-diethyl-3,6-dimethyltetrahydroimidazo[4,5-d]imidazole-2,5 (1H, 3H)-dione in ordinary (H2O) and heavy (D2O) water in comparison with those for Mebicar (1,3,4,6 -tetramethyl-derivative) and Bicaret (1,3,4,6-tetraethyl-derivative). It was concluded that the Albicar hydration is dualistic (hydrophobic-hydrophilic) in nature and enhanced in the D2O medium. In the present report, the missing thermochemical data for solutions of Albicar (as a racemate) in the H/D isotopically distinguishable aqueous media have been analyzed to understand the situation more clearly. Such additional data are the enthalpies of dilution of Albicar solutions in H2O and D2O and the enthalpic coefficients of pairwise interaction (h22) for the title compound in both water isotopologues. Based on the results derived from calorimetric experiments, we have made it clear that the Albicar is a predominantly hydrophilic-hydrated compound despite the presence of two methyl and two ethyl radicals in the molecule of this heterocyclic chiral compound.
Compounds
# Formula Name
1 C10H18N4O2 rac-(3aS,6aS)-1,4-diethyl-3,6-dimethyltetrahydroimidazo[4,5-d]imidazole-2,5(1H,3H)-dione
2 H2O water
3 D2O water-d2
Datasets
The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type Compound-# Property Variable Constraint Phase Method #Points
  • POMD
  • 1
  • Normal melting temperature, K ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal
  • Crystal
  • Liquid
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 2
  • 1
  • Molar enthalpy of dilution, kJ/mol ; Liquid
  • Initial molality of solute, mol/kg; Liquid
  • Final molality of solute, mol/kg; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • ISOPERIBOL
  • 4
  • POMD
  • 3
  • 1
  • Molar enthalpy of dilution, kJ/mol ; Liquid
  • Initial molality of solute, mol/kg; Liquid
  • Final molality of solute, mol/kg; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • ISOPERIBOL
  • 5