Quantum Mechanical Calculations for Reaction Path of O-R Bond Breakage in Some of Cefpodoxime Prodrugs: A Scientific Explanation

Author(s):  
R. M. Kubba
2021 ◽  
Vol 33 (9) ◽  
pp. 2105-2118
Author(s):  
Rehab Majed Kubba ◽  
Aisha Muthana Shanshal

The research includes unrestricted (UDFT) and (UPM3) quantum mechanical calculations for studying the reaction path of bonds rupture energies of (O-R) and (C-OAr) in twelve diclofenac derivatives containing different substituted organic groups. All the calculations were performed at the optimize geometries in vacuum phase by using Gaussian 09 program. Comparison was done between the studied diclofenac derivatives and the standard ionic diclofenac of sodium and potassium included geometrical structures, physical properties, total energies of the reactants and products, activation energies and transition states. The results showed that some substituted organic groups could be used to form good carrier bonds for the acidic drug diclofenac, while others were less efficient depending on the nature of the substituted carrier, and that there is a preference for carriers of the type (–R) over the carriers of the type (–Ar).


2002 ◽  
Vol 67 (4) ◽  
pp. 479-489 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová ◽  
Ladislav Cvak ◽  
Alexandr Jegorov ◽  
...  

Two new structures of semisynthetic ergot alkaloid terguride created by unusual number of symmetry-independent molecules were determined by X-ray diffraction methods at 150 K. Form A (monoclinic, P212121, Z = 12) contains three symmetry-independent terguride molecules and two molecules of water in the asymmetric part of the unit cell. The form CA (monoclinic, P21, Z = 8) is an anhydrate remarkable by the presence of four symmetry-independent molecules in the crystal structure. Conformations of twelve symmetry-independent molecules that were found in four already described terguride structures are compared with torsion angles obtained by ab initio quantum-mechanical calculations for the simplified model of N-cyclohexyl-N'-diethylurea.


2001 ◽  
Vol 567-568 ◽  
pp. 375-384 ◽  
Author(s):  
K.L Bak ◽  
A Halkier ◽  
P Jørgensen ◽  
J Olsen ◽  
T Helgaker ◽  
...  

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