Structural and theoretical evidence of the reaction products of ethyl(ethoxymethylene)cyanoacetate with 5-phenoxymethyl-2-amino-2-oxazoline

DFT study and Monte Carlo simulation on proton transfers of 2-amino-2-oxazoline, 2-amino-2-thiazoline, and 2-amino-2-imidazoline in the gas phase and in water

Density functional theory (DFT) and Monte Carlo (MC) simulation with free energy perturbation (FEP) techniques have been used to study the tautomeric proton transfer reaction of 2-amino-2-oxazoline, 2-amino-2-thiazoline, and 2-amino-2-imidazoline in the gas phase and in water. Two reaction pathways were considered: the direct and water-assisted transfers. The optimized structures and thermodynamic properties of stationary points for the title reaction system in the gas phase were calculated at the B3LYP/6-311+G(d, p) level of theory. The potential energy profiles along the minimum energy path in the gas phase and in water were obtained. The study of the solvent effect of water on the proton transfer of 2-amino-2-oxozoline, 2-amino-2-thiazoline, and 2-amino-2-imidazoline indicates that water as a solvent is favorable for the water-assisted process and slows down the rate of the direct transfer pathway.

Derivatization of (+/-)-5-[(2-methylphenoxy)methyl]-2-amino-2-oxazoline, an imidazoline binding sites ligand, with (+)-(R)-alpha-methylbenzyl isocyanate for drug monitoring purposes

The derivatization of racemic 5-[(2-methylphenoxy)methyl]-2-amino-2-oxazoline, developed as an imidazoline binding sites ligand, with (+)-(R)-alpha-methylbenzyl isocyanate was performed in chloroform. The reaction led to two pairs of diastereomers, which were separated by RP-HPLC. A kinetic study of the derivatization reaction was achieved in order to establish conditions suitable for experimental drug monitoring.

An ab initio investigation of 2-amino-2-imidazoline: a key moiety in chemical and biochemical processes

The 2-amino-2-imidazoline moiety is currently used not only in drugs, but also in insecticides, and fungicides. Ab initio calculations are performed to evaluate the molecular properties of the two tautomeric forms and the protonated form with extended basis sets ranging from 6-31G* to 6-311++G** at Hartree-Fock and density functional (BLYP and B3LYP) levels. Møller-Plesset perturbation is tested at the MP2/6-31G* level only. Optimized geometry structures, energies and thermochemical properties are generated. Basis set and correlation effects on geometries, tautomer equilibrium constant and protonation enthalpy are carefully analysed. Although observed for the isolated molecule, these results may be extrapolated to chemical and biochemical systems of interest.