82744-94-3Relevant academic research and scientific papers
RELATIONSHIPS OF TRANSAMINATION OF SUBSTITUTED UREAS. V. THERMODYNAMICS OF TRANSAMINATION OF DIARYLUREAS BY DIALKYLAMINES
Chimishkyan, A. L.,Gulyaev, N. D.,Leonova, T. V.
, p. 20 - 24 (2007/10/02)
The equilibrium constant of the transamination of N,N'-diarylureas by dialkylamines in o-dichlorobenzene in the range of 120-158 deg C depends significantly on the nature of both reagents.The enthalpy of activation and the entropy of dissociation of diarylureas are proportional to the thermal effect of the transamination of these ureas by diisobutylamine.The same relationships is observed between the enthalpy of activation of the bimolecular reaction of N,N'-diphenylurea with dialkylamines and the enthalpy of the process.The established relationships between the enthalpies of activation and the enthalpy of equilibrium are explained satisfactorily in terms of the Hammond-Thornton model.
RELATIONSHIPS IN THE TRANSAMINATION OF SUBSTITUTED UREAS. IV. TRANSAMINATION OF SYMMETRICAL DIARYLUREAS BY DIISOBUTYLAMINE
Chimishkyan, A. L.,Gulyaev, N. D.,Leonova, T. V.
, p. 1845 - 1848 (2007/10/02)
The effect of substituents in N,N'-diarylureas on the kinetics of transamination by diisobutylamine differs for each of the reaction paths.For the dissociation of ureas ρ1 = -0.34, and for their bimolecular reaction with diisobutylamine ρ3 = 1.05 (o-dichlorobenzene, 142 deg C).At the same time both reactions obey an isokinetic law: β1 441 deg K, β2 357 deg K.The controlling stage of each of the paths takes place through a four-center concerted transition state.
INFRARED SPECTROSCOPIC AND CONFORMATIONAL STUDIES OF TRISUBSTITUTED UREAS CONTAINING CHLOROPHENYL GROUPS
Mido, Yoshiyuki,Furusawa, Chizuko
, p. 23 - 28 (2007/10/02)
The IR spectra, in the ν(N-H) region, of trisubstituted ureas R2UPhCl and RPhUPhCl containing a chlorophenyl group have been studied in order to examine the effects of the introduced chlorine atom.The out-trans-cis isomerism about the NH-CO rotational axis is discussed in reation to steric effect of the R2 group, Ph-Ph interaction and inter- and intra-molecular hydrogen bonding.In dilute solution, R2UPhCl exists in the trans or the out form, and RPhUPhCl in the cis form. o-Chlorophenyl derivatives show a monomeric ν(N-H) band at a wavenumber lower than that of the other derivatives and no associated ν(N-H) bands in concentrated or even in saturated solutions.Some of the derivatives are found to be in the same form in the solid state as in solution due to the retention of intra-molecular NH...Cl hydrogen bonding.
