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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1992-4-16
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pubmed:abstractText |
The preferred conformations and self-association modes of the two diastereomeric N-acetyl, methylamides of 3-hydroxy, 4-amino, 5-methylhexanoic acid ("Val"-statine) with (S,S) and (R,S) configurations at the 3-hydroxy and 4-amino carbon atoms, respectively, were determined in solution as well as in the crystal state by infrared absorption, 1H nuclear magnetic resonance and x-ray diffraction. A corollary conformational energy computation study was also carried out. In the crystal state intramolecular H-bonds are absent in both structures. However, the change in chirality of the carbon atom carrying the hydroxy group and the presence of a co-crystallized water molecule in the (S,S) isomer induce partially different backbone and "Val" side chain conformations and divergent intermolecular H-bonding schemes in the two isomers. A marked propensity to self-aggregate is seen in solvents of low polarity. The two isomers, however, are largely solvated in solvents of high polarity. Conformational energy computations indicate that in vacuo both diastereomers exhibit a significant flexibility and the conformers presenting absolute minima are not stabilized by any intramolecular bonding.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:issn |
1040-5704
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
3
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
27-34
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pubmed:dateRevised |
2000-12-18
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pubmed:meshHeading |
pubmed-meshheading:2134045-Amino Acid Sequence,
pubmed-meshheading:2134045-Amino Acids,
pubmed-meshheading:2134045-Hydrogen Bonding,
pubmed-meshheading:2134045-Magnetic Resonance Spectroscopy,
pubmed-meshheading:2134045-Molecular Sequence Data,
pubmed-meshheading:2134045-Protein Conformation,
pubmed-meshheading:2134045-Solutions,
pubmed-meshheading:2134045-Stereoisomerism,
pubmed-meshheading:2134045-Valine,
pubmed-meshheading:2134045-X-Ray Diffraction
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pubmed:articleTitle |
Theoretical and experimental conformational analysis of two diastereomeric "Val"-statine derivatives.
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pubmed:affiliation |
Department of Organic Chemistry, University of Padova, Italy.
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pubmed:publicationType |
Journal Article
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