scholarly journals Conformational Analysis in 18-Membered Macrolactones Based on Molecular Modeling

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Salah Belaidi ◽  
Dalal Harkati
Keyword(s):  
Molecular Dynamics ◽  
Molecular Modeling ◽  
Conformational Analysis ◽  
Molecular Mechanics ◽  
Conformational Flexibility ◽  
Molecular Mechanics Calculations

Conformational analysis of 18-ring membered macrolactones has been carried out using molecular mechanics calculations and molecular dynamics. A high conformational flexibility of macrolactones was obtained, and an important stereoselectivity was observed for the complexed macrolides. For 18d macrolactone, which was presented by a most favored conformer with 20.1% without complex, it was populated with 50.1% in presence of Fe(CO)3.

Conformational analysis of acetylcholine and related choline esters

1996 ◽  
Vol 52 (1) ◽  
pp. 184-193 ◽  
Author(s):  
K. Frydenvang ◽  
B. Jensen
Keyword(s):  
Conformational Analysis ◽  
Molecular Mechanics ◽  
Conformational Flexibility ◽  
Accurate Information ◽  
Ammonium Ions ◽  
Molecular Mechanics Calculations ◽  
X Ray ◽  
Quaternary Ammonium Ions ◽  
Choline Esters ◽  
Mm2 Calculations

The crystal structures of carbamoylcholine [2-(carbamoyloxy)-N,N,N-trimethylethanaminium] chloride, bromide and iodide, methoxycarbonylcholine [2-(methoxycarbonyloxy)-N,N,N-trimethylethanaminium] iodide, acetylcholine [2-(acetyloxy)-N,N,N-trimethylethanaminium] chloride and succinylcholine { 2,2′-[(1,4-dioxo-1,4-butanediyl)bis(oxy)]bis(N,N,N-trimethylethanaminium)} iodide have been redetermined at 105 K in order to obtain detailed and accurate information on the geometry of choline esters and to elucidate the conformationally dependent changes of geometry. The conformational flexibility and the preferred conformations are elucidated based on results obtained from X-ray crystallographic studies and molecular mechanics (MM2) calculations. The usefulness of molecular mechanics calculations for quaternary ammonium ions is discussed.

Molecular Modeling of Slip Supposed to Occur in the Shock Initiation of Crystalline PETN

1992 ◽  
Vol 296 ◽  
Author(s):  
James P. Ritchie
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Molecular Modeling ◽  
Molecular Mechanics ◽  
Molecular Mechanics Calculations ◽  
Rigid Displacement ◽  
Shock Initiation ◽  
Flexible Molecules ◽  
Finite Lattices ◽  
Molecular Deformations

AbstractSome molecular modeling of slip using both rigid and flexible molecules of PETN in perfect, but finite, lattices has been performed. Studies of rigid displacement show slip on (001)<010> to be relatively unhindered. The shock orientation with a maximum resolved shear stress in this direction would, therefore, be expected to be insensitive. Molecular mechanics calculations have also been performed. The results show that it is likely that molecular deformations occur and have an important effect in determining the shear strength of crystalline PETN.

Sign in / Sign up

Export Citation Format

Share Document