Several 3-aminoquinazolin-4-(3H)-one derivatives were synthesized and characterized.Using proton nuclear magnetic resonance (NMR) spectra,we have investigated the barriers to rotation around the N ― N bond as a funct...Several 3-aminoquinazolin-4-(3H)-one derivatives were synthesized and characterized.Using proton nuclear magnetic resonance (NMR) spectra,we have investigated the barriers to rotation around the N ― N bond as a function of temperature.Changes in the NMR spectra at high temperatures are explained in terms of hindered rotations of the N ― N bond.Free energies of activation for the rate determining stereochemical process were calculated to be as high as 67-75 kJ · mol-1.Ground state molecular geometries and vibrational frequencies were calculated using the HF/6-31G and B3LYP/6-31G level of theories.The optimized bond lengths and bond angles are in good agreement with experimental values at both theoretical levels.展开更多
基金AL-AMRI Reem S. Abdulaziz was supported by the King Abdul Aziz City of Science and Technology (KACST) (GSP-18-138)
文摘Several 3-aminoquinazolin-4-(3H)-one derivatives were synthesized and characterized.Using proton nuclear magnetic resonance (NMR) spectra,we have investigated the barriers to rotation around the N ― N bond as a function of temperature.Changes in the NMR spectra at high temperatures are explained in terms of hindered rotations of the N ― N bond.Free energies of activation for the rate determining stereochemical process were calculated to be as high as 67-75 kJ · mol-1.Ground state molecular geometries and vibrational frequencies were calculated using the HF/6-31G and B3LYP/6-31G level of theories.The optimized bond lengths and bond angles are in good agreement with experimental values at both theoretical levels.
