ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In this paper we have successfully applied the dicyclohexylcarbodiimide and the acylazide coupling methods to the synthesis of a series of L-isoleucine peptides from dimer to octamer. In the course of our synthetic, approach we employed t-butyloxycarbonyl as the N-protecting and methyl ester as the C-protecting end groups. Peptide coupling reactions known to give products of high optical purity in good yields were used in these researches. Finally, we described preliminary stereochemical investigations on these homo-oligopeptides using polarimetric and ultraviolet, absorption techniques. The con-formational properties of high molecular weight poly-α-amino acids have attracted considerable attention as protein model compounds. In addition, investigations performed on oligopeptides have yielded important information concerning the dependence of secondary structure on chain length. Goodman and co-workers2-5 have conducted extensive studies on the critical size for helix formation in L-alanine, L-aspartate and L-glutamate oligomers and cooligomers. By a variety of techniques, they demonstrated that the onset of secondary structure is dependent both on the solvent and the nature of the side chain. In this and in the accompanying6 paper we report the extension of this approach to homo-oligopeptides derived from L-isoleucine, which is considered to be disruptive of α-helices for steric reasons7 in proteins and polypeptides. In particular this manuscript will describe the synthesis of the homologous series of BOC-L-(Ileu)n-OMe* (n = 2-8) and preliminary stereochemical investigations by means of polarimetry and ultraviolet (UV) spectroscopy. In the accompanying paper a much more detailed analysis of the stereochemistry of these oligopeptides will be reported.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360100923
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