An improved approach for the synthesis of α,α-dialkyl glycine derivatives by the Ugi–Passerini reactionElectronic supplementary information (ESI) available: spectroscopic data for compounds 1-5. See http://www.rsc.org/suppdata/ob/b2/b212473b/
An improved approach for the synthesis of α,α-dialkyl glycine derivatives by the Ugi–Passerini reactionElectronic supplementary information (ESI) available: spectroscopic data for compounds 1-5. See http://www.rsc.org/suppdata/ob/b2/b212473b/
Several fully protected tri- and pentapeptides containing a central symmetrical alpha,alpha-dialkyl glycine residue, with the alkyl group varying from methyl or ethyl to benzyl, were synthesized in good yields by a strategy based on the Ugi-Passerini reaction. Each Ugi-Passerini adduct was selectively cleaved and the product submitted to an assisted N,N'-dicyclohehylcarbodiimide coupling to an amino acid or dipeptide ester, respectively. Tripeptides as the above but containing a 4-methoxybenzyl group at the nitrogen atom of the central residue were also synthesized in fair to good yields by N-[(1H-benzotriazol-1-yl)(dimethylamino)methylene]-N-methylmethanaminium hexafluorophosphate N-oxide assisted couplings. The results reported here show that our strategy is appropriate for routine synthesis of peptides incorporating these moieties. (C) 2009 Elsevier Ltd. All rights reserved.
An improved approach for the synthesis of α,α-dialkyl glycine derivatives by the Ugi–Passerini reactionElectronic supplementary information (ESI) available: spectroscopic data for compounds 1-5. See http://www.rsc.org/suppdata/ob/b2/b212473b/
作者:Susana P. G. Costa、Hernâni L. S. Maia、Sílvia M. M. A. Pereira-Lima
DOI:10.1039/b212473b
日期:2003.4.23
A general and simple strategy for routine peptide synthesis with α,α-dialkyl glycines taking advantage of the four-component UgiâPasserini reaction is presented. The isonitrile required for the reaction can be relatively simple and its selection based on cost, as the group it generates is easily removed under acidic conditions; in addition, this removal is not visibly affected by the bulkiness of the α-alkyl groups. Being a good leaving group from the N-terminal amino group of the amino acid, 4-methoxybenzyl was the choice for the amine component of the reaction. The method is illustrated with the synthesis of a series of acyl derivatives of several α,α-dialkyl glycines. The preparation of the latter compounds is also reported.