The Hydrogen-Bonding Ability of the Amino Acid Glutamine Revealed by Neutron Diffraction Experiments

2012 ◽  
Vol 116 (45) ◽  
pp. 13308-13319 ◽  
Author(s):  
N. H. Rhys ◽  
A. K. Soper ◽  
L. Dougan
Author(s):  
Z. Cheng ◽  
Y. Cheng ◽  
L. Guo ◽  
D. Xu

AbstractThe crystal structure of the title compound D(H)LAP with chemical formula (D


Synlett ◽  
2020 ◽  
Author(s):  
Xiaohua Liu ◽  
Yi Li ◽  
Hao Pan ◽  
Wang-Yuren Li ◽  
Xiaoming Feng

AbstractAn asymmetric organocatalytic nucleophilic aromatic substitution reaction of azlactones with electron-deficient aryls was established. A variety of α-aryl α-alkyl α-amino acid esters and peptides were obtained in decent yields and stereoselectivities. A new bifunctional catalytic mode involving charge-transfer interaction and hydrogen bonding is proposed to explain the enantioselectivity.


2009 ◽  
Vol 08 (04) ◽  
pp. 691-711 ◽  
Author(s):  
FENG FENG ◽  
HUAN WANG ◽  
WEI-HAI FANG ◽  
JIAN-GUO YU

A modified semiempirical model named RM1BH, which is based on RM1 parameterizations, is proposed to simulate varied biological hydrogen-bonded systems. The RM1BH is formulated by adding Gaussian functions to the core–core repulsion items in original RM1 formula to reproduce the binding energies of hydrogen bonding of experimental and high-level computational results. In the parameterizations of our new model, 35 base-pair dimers, 18 amino acid residue dimers, 14 dimers between a base and an amino acid residue, and 20 other multimers were included. The results performed with RM1BH were compared with experimental values and the benchmark density-functional (B3LYP/6-31G**/BSSE) and Möller–Plesset perturbation (MP2/6-31G**/BSSE) calculations on various biological hydrogen-bonded systems. It was demonstrated that RM1BH model outperforms the PM3 and RM1 models in the calculations of the binding energies of biological hydrogen-bonded systems by very close agreement with the values of both high-level calculations and experiments. These results provide insight into the ideas, methods, and views of semiempirical modifications to investigate the weak interactions of biological systems.


CrystEngComm ◽  
2018 ◽  
Vol 20 (43) ◽  
pp. 6970-6981 ◽  
Author(s):  
Artem O. Surov ◽  
Alexander P. Voronin ◽  
Mikhail V. Vener ◽  
Andrei V. Churakov ◽  
German L. Perlovich

New zwitterionic cocrystals of fenamate drugs and diclofenac with the naturally occurring amino acid l-proline have been obtained and thoroughly characterised by a variety of experimental and theoretical techniques.


2019 ◽  
Vol 21 (39) ◽  
pp. 21782-21789 ◽  
Author(s):  
Adam H. Turner ◽  
John D. Holbrey

Neutron scattering reveals the persistent three-dimensional hydrogen-bonding network between glycerol molecules in the 1 : 2 choline chloride/glycerol eutectic.


Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 515 ◽  
Author(s):  
David B. Hobart ◽  
Joseph S. Merola ◽  
Hannah M. Rogers ◽  
Sonia Sahgal ◽  
James Mitchell ◽  
...  

Palladium(II) acetate reacts with proline and proline homologs in acetone/water to yield square planar bis-chelated palladium amino acid complexes. These compounds are all catalytically active with respect to oxidative coupling of olefins and phenylboronic acids. Some enantioselectivity is observed and formation of products not reported in other Pd(II) oxidative couplings is seen. The crystal structures of nine catalyst complexes were obtained. Extended lattice structures arise from N-H••O or O••(HOH)••O hydrogen bonding. NMR, HRMS, and single-crystal XRD data obtained on all are evaluated.


2019 ◽  
Vol 15 ◽  
pp. 2419-2427
Author(s):  
Sachin S Burade ◽  
Sushil V Pawar ◽  
Tanmoy Saha ◽  
Navanath Kumbhar ◽  
Amol S Kotmale ◽  
...  

The intramolecular cyclization of a C-3-tetrasubstituted furanoid sugar amino acid-derived linear tetrapeptide afforded an oxazolone pseudo-peptide with the formation of an oxazole ring at the C-terminus. A conformational study of the oxazolone pseudo-peptide showed intramolecular C=O···HN(II) hydrogen bonding in a seven-membered ring leading to a γ-turn conformation. This fact was supported by a solution-state NMR and molecular modeling studies. The oxazolone pseudotetrapeptide was found to be a better Cl−-selective transporter for which an anion–anion antiport mechanism was established.


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