Linked Life Data

1819592

Source:http://linkedlifedata.com/resource/pubmed/id/1819592

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1992-7-29
pubmed:abstractText
The asymmetric induction occurring during aminolysis by an amino acid benzyl ester of the 5(4H)-oxazolones obtained from N-acyl-DL-valine for acyl = formyl, acetyl, benzoyl, trifluoroacetyl and N-benzyloxycarbonyl-Xaa where Xaa = Gly, Ala and Leu in dichloromethane and dimethylformamide at +5 degrees and -5 degrees was determined by analysis of the epimeric products by high-performance liquid chromatography after removal of protecting groups by hydrogenolysis. The influence of the side-chain of the activated residue on induction was assessed by examining aminolysis of the 5(4H)-oxazolones from N-benzyloxycarbonyl glycyl-Xaa-OH for Xaa = Ala, Leu, Val, and Phe. The contribution of induction to the epimeric content of products obtained from couplings mediated by N,N'-dicyclohexylcarbodiimide in the presence and absence of l-hydroxybenzotriazole, and by the mixed-anhydride method, were calculated. The induction was affected at varying levels by the nature of the N-acyl group, the side-chain of Xaa, the nature of the aminolyzing nucleophile, the nature of the solvent, and the temperature, with diastereomeric excesses reaching -32 and +53. The influence of the side-chain of Xaa on the induction was different in the two solvents. For the N-acyl series, the epimeric content of products did not always correctly reflect the relative tendencies of the derivatives to racemize. The order for epimeric content of the products also depended on the method of coupling.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0367-8377
pubmed:author
pubmed:issnType
Print
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
574-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Studies on asymmetric induction associated with the coupling of N-acylamino acids and N-benzyloxycarbonyldipeptides.
pubmed:affiliation
Department of Biochemistry, University of Ottawa, Ontario, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't