Multicyclic polypeptide model compounds. 2. Synthesis and conformational properties of a highly .alpha.-helical uncosapeptide constrained by three side-chain to side-chain lactam bridges

1992 ◽  
Vol 114 (18) ◽  
pp. 6966-6973 ◽  
Author(s):  
George Osapay ◽  
John W. Taylor
Keyword(s):  
Side Chain ◽  
Model Compounds ◽  
Conformational Properties ◽  
Lactam Bridges

Conformational properties of macromolecules with side chain groups. Polycholesterylacrylate

1972 ◽  
Vol 14 (2) ◽  
pp. 478-484 ◽  
Author(s):  
V.N. Tsvetkov ◽  
Ye.V. Korneyeva ◽  
I.N. Shtennikova ◽  
P.N. Lavrenko ◽  
G.F. Kolbina ◽  
...  
Keyword(s):  
Side Chain ◽  
Conformational Properties

Convenient preparation of a β-O-4-type lignin model trimer via KOH-catalyzed hydroxymethylation and a new protection method

Holzforschung ◽  
2013 ◽  
Vol 67 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Maarit Lahtinen ◽  
Anssi Haikarainen ◽  
Jussi Sipilä
Keyword(s):  
Model Compound ◽  
Catalytic Amount ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
Chemical Behavior ◽  
Model Compounds ◽  
Protection Method ◽  
Convenient Synthesis ◽  
Lignin Model ◽  
Convenient Preparation

Abstract Lignin, as the second most abundant biopolymer on earth, is one of the targets for plant biorefinery studies. Its complex chemical behavior is frequently studied by dimeric, trimeric, etc. model compounds, preferably with a β-O-4-type structure. In the present study, a convenient synthesis of a β-O-4-type trimeric model compound possessing a free syringylic hydroxyl has been investigated. Two key modifications were in focus: (1) Protection of the aliphatic hydroxyl groups of the starting phenolic dimer prior to the SN2 displacement reaction before introducing the syringylic moiety with 2,2-dimethoxypropane. (2) The hydroxymethylation step to introduce the full side chain moiety. When this reaction was performed in dioxane/water in the presence of a catalytic amount of KOH instead of K2CO3, the formation of a side product via dehydration was markedly reduced. In addition, a convenient method for introducing an α,β-epoxide structure in acetophenone is recommended.

Conformational analysis of the disaccharide methyl α-D-mannopyranosyl-(1→3)-2-O-acetyl-β-D-mannopyranoside monohydrate

2019 ◽  
Vol 75 (6) ◽  
pp. 610-615 ◽  
Author(s):  
Wenhui Zhang ◽  
Qingquan Wu ◽  
Allen G. Oliver ◽  
Anthony S. Serianni
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Nmr Spectroscopy ◽  
Structural Parameters ◽  
Side Chain ◽  
Glycosidic Linkage ◽  
Torsion Angles ◽  
Conformational Properties ◽  
Statistical Program ◽  
Acetyl Group

The crystal structure of methyl α-D-mannopyranosyl-(1→3)-2-O-acetyl-β-D-mannopyranoside monohydrate, C15H26O12·H2O, (II), has been determined and the structural parameters for its constituent α-D-mannopyranosyl residue compared with those for methyl α-D-mannopyranoside. Mono-O-acetylation appears to promote the crystallization of (II), inferred from the difficulty in crystallizing methyl α-D-mannopyranosyl-(1→3)-β-D-mannopyranoside despite repeated attempts. The conformational properties of the O-acetyl side chain in (II) are similar to those observed in recent studies of peracetylated mannose-containing oligosaccharides, having a preferred geometry in which the C2—H2 bond eclipses the C=O bond of the acetyl group. The C2—O2 bond in (II) elongates by ∼0.02 Å upon O-acetylation. The phi (φ) and psi (ψ) torsion angles that dictate the conformation of the internal O-glycosidic linkage in (II) are similar to those determined recently in aqueous solution by NMR spectroscopy for unacetylated (II) using the statistical program MA′AT, with a greater disparity found for ψ (Δ = ∼16°) than for φ (Δ = ∼6°).

Structural and Thermodynamic Characterization of a Bioactive Peptide Model of Apolipoprotein E: Side-Chain Lactam Bridges To Constrain the Conformation

Biochemistry ◽  
1994 ◽  
Vol 33 (41) ◽  
pp. 12367-12377 ◽  
Author(s):  
Peizhi Luo ◽  
Demetrios T. Braddock ◽  
Ram M. Subramanian ◽  
Stephen C. Meredith ◽  
David G. Lynn
Keyword(s):  
Apolipoprotein E ◽  
Bioactive Peptide ◽  
Side Chain ◽  
Thermodynamic Characterization ◽  
Lactam Bridges

Correlation of Model Compounds and Laterally Attached Side-Chain Liquid-Crystalline Polynorbornenes with an 11-Carbon Spacer

1998 ◽  
Vol 31 (6) ◽  
pp. 1779-1790 ◽  
Author(s):  
Coleen Pugh ◽  
Jun Shao ◽  
Jason J. Ge ◽  
Stephen Z. D. Cheng
Keyword(s):  
Liquid Crystalline ◽  
Side Chain ◽  
Model Compounds

Conformational Properties of Model Compounds of Imide-Ether Molecular Chains

1994 ◽  
Vol 27 (26) ◽  
pp. 7689-7694
Author(s):  
M. L. Jimeno ◽  
J. G. de la Campa ◽  
E. Riande ◽  
J. de Abajo ◽  
J. M. Garcia
Keyword(s):  
Model Compounds ◽  
Conformational Properties
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