نتایج جستجو برای: conformations analysis

تعداد نتایج: 2835289  

Journal: :The Journal of organic chemistry 1997
A. Entrena J. Campos J. A. Gómez M. A. Gallo A. Espinosa

The chair and twist-chair conformations of seven-membered rings are classified as a function of the signs of their endocyclic torsion angles. The conformational analysis (MM3) of the methoxy- and methyloxepanes 1-6 used as patterns allows the study and classification of the different types of hydrogen orientation in the seven-membered saturated heterocycles. General principles are established, ...

Journal: :Bioorganic & medicinal chemistry 2008
Dongmei Han F Holger Försterling Xiaoyan Li Jeffrey R Deschamps Damon Parrish Hui Cao Sundari Rallapalli Terry Clayton Yun Teng Samarpan Majumder Subramaniam Sankar Bryan L Roth Werner Sieghart Roman Furtmuller James K Rowlett Michael R Weed James M Cook

The stable conformations of GABA(A)-benzodiazepine receptor bivalent ligands were determined by low temperature NMR spectroscopy and confirmed by single crystal X-ray analysis. The stable conformations in solution correlated well with those in the solid state. The linear conformation was important for these dimers to access the binding site and exhibit potent in vitro affinity and was illustrat...

Journal: :Organic letters 2006
Gang Cheng Fabien P Boulineau Siong-Tern Liew Qicun Shi Paul G Wenthold Alexander Wei

The high facioselectivity in the epoxidation of 4-deoxypentenosides (4-DPs) by dimethyldioxirane (DMDO) correlates with a stereoelectronic bias in the 4-DPs' ground-state conformations, as elucidated by polarized-pi frontier molecular orbital (PPFMO) analysis.

Journal: :Zeitschrift für anorganische und allgemeine Chemie 2022

Abstract Metaphosphimates are possible precursors for oxonitridophosphates. A new polymorph of trimetaphosphimic acid, in fact an oxonium trimetaphosphimate monohydrate, crystallizes the monoclinic space group P 2 1 / c . It exhibits coin‐roll‐like stacks H (PO NH) 3 − anions a rectangular pattern, whereas these form hexagonal arrangement known polymorph. Ring conformation analysis reveals stat...

2003

Preview You learned in the Chapter 1 that all organic molecules have carbon skeletons. These carbon skeletons show great diversity in the ways that C atoms bond to each other, and in their three-dimensional shapes. Alkanes and cycloalkanes consist entirely of carbon skeletons bonded to H atoms since they have no functional groups. As a result, they serve as a basis for understanding the structu...

Journal: :Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics 1999
B Fain J Rudnick

We examine the conformations of a model for a short segment of closed DNA. The molecule is represented as a cylindrically symmetric elastic rod with a constraint corresponding to a specification of the linking number. We obtain analytic expressions leading to the spatial configuration of a family of solutions representing distortions that interpolate between the circular form of DNA and a figur...

1999
Robert R. Hudgins Yi Mao Mark A. Ratner Martin F. Jarrold

High-resolution ion mobility measurements and molecular dynamics simulations have been used to probe the conformations of protonated polyglycine and polyalanine (GlynH 1 and AlanH , n 5 3–20) in the gas phase. The measured collision integrals for both the polyglycine and the polyalanine peptides are consistent with a self-solvated globule conformation, where the peptide chain wraps around and s...

2012
Ulrich Burkert

The geometries and energies of the conformers of oxocane, the isomeric diand trioxocanes, and of 1,3,5,7-tetroxocane were calculated by molecular mechanics. A boat-chair conformation was preferred by all molecules. From the preference of oxygen in the boat-chair conformations of oxocane (position 3 over 1 over 4) the preferred boat-chair form of all other oxocanes can be derived. The results ar...

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