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‘ O ‐Acyl isopeptide method’ for peptide synthesis: Solvent effects in the synthesis of Aβ1–42 isopeptide using ‘ O ‐acyl isodipeptide unit’
Author(s) -
Taniguchi Atsuhiko,
Yoshiya Taku,
Abe Naoko,
Fukao Fukue,
Sohma Youhei,
Kimura Tooru,
Hayashi Yoshio,
Kiso Yoshiaki
Publication year - 2007
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.905
Subject(s) - chemistry , solvent , peptide , side chain , acylation , coupling reaction , intramolecular force , combinatorial chemistry , peptide synthesis , acyl group , stereochemistry , organic chemistry , catalysis , biochemistry , group (periodic table) , polymer
‘ O ‐Acyl isopeptide method’ is an efficient synthetic method for peptides. We designed ‘ O ‐acyl isodipeptide units’, Boc‐Ser/Thr(Fmoc‐Xaa)‐OH, as important building blocks to enable routine use of the O ‐acyl isopeptide method. In the synthesis of an Aβ1–42 isopeptide using O ‐acyl isodipeptide unit Boc–Ser(Fmoc–Gly)–OH, a side reaction, resulting in the deletion of Ser 26 in the O ‐acyl isopeptide structure, was noticed during coupling of the unit. We observed that the side reaction occurred during the activation step and was solvent‐dependent. In DMF or NMP, an intramolecular side reaction, originating from the activated species of the unit, occurred during the activation step. In non‐polar solvents such as CHCl 3 or CH 2 Cl 2 , the side reaction was less likely to occur. Using CH 2 Cl 2 as solvent in coupling the unit, the target Aβ1–42 isopeptide was synthesized with almost no major side reaction. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.