Synthesis of All Nineteen Appropriately Protected Chiral α-Hydroxy Acid Equivalents of the α-Amino Acids for Boc Solid-Phase Depsi-Peptide Synthesis
作者:Songpon Deechongkit、Shu-Li You、Jeffery W. Kelly
DOI:10.1021/ol036102m
日期:2004.2.1
The preparation of depsi-peptides, amide-to-ester-substituted peptides used to probe the role of hydrogen bonding in protein folding energetics, is accomplished by replacing specific L-alpha-amino acid residues by their alpha-hydroxy acid counterparts in a solid-phase synthesis employing a t-Boc strategy. Herein we describe the efficient stereoselective synthesis of all 19 appropriately protected alpha-hydroxy acid equivalents of the L-alpha-amino acids, employing commercially available materials, expanding the number of available alpha-hydroxy acids from 9 to 19.
Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids
procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-aminoacid with tert-butyl nitrite in 1,4-dioxane–water. The amino moiety must be protonated and located α to a carboxylic acidfunction in order to undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acidderivatives such as esters and amides undergo