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Synthesis and Structural Analysis of Cyclic Oligomers Consisting of Furanoid and Pyranoid ϵ‐Sugar Amino Acids
Author(s) -
Well Renate M. van,
Marinelli Luciana,
Erkelens Kees,
Marel Gijsbert A. van der,
Lavecchia Antonio,
Overkleeft Herman S.,
Boom Jacques H. van,
Kessler Horst,
Overhand Mark
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300031
Subject(s) - chemistry , trimer , stereochemistry , peptidomimetic , side chain , amide , peptide , organic chemistry , biochemistry , dimer , polymer
Cyclic oligomers composed of amide‐linked furanoid (i.e., 1 , 3 ) and pyranoid (i.e., 2 , 4 ) ϵ‐sugar amino acids (SAAs) were prepared by a cyclization/cleavage approach with use of the oxime resin. These cyclic homooligomers were constructed by use of the known N ‐Boc protected furanoid ϵ‐SAA 11 and the novel pyranoid hydroxymethylene homologue 22 . Conformational analysis of cyclic trimer 1 by an unrestrained simulated annealing technique showed that the furanoid rings of the residues I flip between a twist (north, P = 0°) and an envelope (south, P = 167°) conformation. Furthermore, the side chains connecting the carbonyl functionality (i.e. C2) proved to be rigid, while the other side chains (C7) are conformationally flexible. Similar conformational behaviour is observed for the side chains of the pyranoid ϵ‐SAA II residues in trimer 2 , but the pyranoid ring chair conformation remains stable during the calculation. These conformational details may have important implications in the future design of SAA‐based artificial receptors or peptidomimetics. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)