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Lewis acid catalysed methylation of N ‐(9H‐fluoren‐9‐yl)methanesulfonyl (Fms) protected lipophilic α ‐amino acid methyl esters
Author(s) -
Leggio Antonella,
Alò Danila,
Belsito Emilia Lucia,
Di Gioia Maria Luisa,
Romio Emanuela,
Siciliano Carlo,
Liguori Angelo
Publication year - 2015
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.2777
Subject(s) - racemization , chemistry , diazomethane , methylation , diastereomer , reagent , amino acid , organic chemistry , methyl group , protecting group , group (periodic table) , biochemistry , alkyl , gene
This work reports an efficient Lewis acid catalysed N ‐methylation procedure of lipophilic α ‐amino acid methyl esters in solution phase. The developed methodology involves the use of the reagent system AlCl 3 /diazomethane as methylating agent and α ‐amino acid methyl esters protected on the amino function with the (9H‐fluoren‐9‐yl)methanesulfonyl (Fms) group. The removal of Fms protecting group is achieved under the same conditions to those used for Fmoc removal. Thus the Fms group can be interchangeable with the Fmoc group in the synthesis of N ‐methylated peptides using standard Fmoc‐based strategies. Finally, the absence of racemization during the methylation reaction and the removal of Fms group were demonstrated by synthesising a pair of diastereomeric dipeptides. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.