N-Methyl-beta(3)-amino acids are important building blocks in the synthesis of biologically active molecules. A very simple and efficient approach to transform natural alpha-amino acids into their corresponding N-methyl-beta(3)-amino acids is here presented. In the method, the key intermediates N-methyl-N-nosyl-alpha-aminoacyldiazomethanes are prepared in only one step, by a simple treatment of the corresponding N-nosyl-alpha-aminoacyl chlorides with diazomethane. The synthetic route takes advantage from the use of the nosyl group. This N-masking moiety activates the NH function, and the N-methylation can directly occur during the acylation step of diazomethane, rendering useless a second step that instead is shown to be necessary in all the classical procedures already reported for the preparation of N-methyl-beta(3)-amino acids. The Wolff rearrangement of N-methyl-N-nosyl-alpha-aminoacyldiazomethanes provides the corresponding N-methyl-N-nosyl-beta(3)-amino acids with total retention of the chiral configuration of the starting alpha-amino acids. No epimerization of the chiral carbon atom is observed also when N-methyl-N-nosyl-beta(3)-amino acids are transformed into chlorides and coupled with alpha-amino acid methyl esters to achieve model scaffolds for biologically important modified peptides.
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|Data di pubblicazione:||2007|
|Citazione:||N-Methyl-N-Nosyl-β3-amino acids / Belsito, E; DI GIOIA, Maria Luisa; Greco, A; Leggio, Antonella; Liguori, Angelo; Perri, F; Siciliano, Carlo; Viscomi, M. C.. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 72:13(2007), pp. 4798-4802.|
|Appare nelle tipologie:||1.1 Articolo in rivista|