Solution synthesis of a dimeric pentapeptide: Diketopiperazine cyclisation of Glu-Asp dipeptide esters and Asp-racemisation during segment condensation
作者:Peter M. Fischer、Magne Solbakken、Kjell Undheim
DOI:10.1016/s0040-4020(01)85085-7
日期:1994.2
A haemoregulatory peptide analogue derived from the cystine-dimerised pentapeptide Glp-Glu-Asp-Cys-Lys-OH, in which the cystine residue has been replaced by an isosteric L,L-2,7-diaminosuberic acid moiety, was prepared by segment condensation in solution. The preparation of protected Glp-Glu-Asp-OH tripeptides was found to be hampered by the surprising ease with which t-butyl side-chain protected H-Glu-Asp-OR
Useful intermediates for synthesis of dicarba analogs of cystine peptides: selectively protected .alpha.-aminosuberic acid and .alpha.,.alpha.'-diaminosuberic acid of defined stereochemistry
作者:Ruth F. Nutt、Robert G. Strachan、Daniel F. Veber、Frederick W. Holly
DOI:10.1021/jo01303a028
日期:1980.7
Efficient Synthesis of Differentially Protected (S,S)-2,7- Diaminooctanedioic Acid, the Dicarba Analogue of Cystine
Convenient preparative syntheses of differentially protected forms of (S,S)-2,7-diaminooctanedioic acid (2), suitable for application in peptide chemistry, are described. The key compound, the di-Cbz-protected phenacyl monoester 7a (Cbz = [(benzyloxy)carbonyl]), was obtained by means of Schollkopf bis-lactim ether methodology and optimized monoesterification procedures. Selective amino deprotection at the non-esterified amino-acid function of 7a by dichloromethyl-methyl-ether-induced 'N-carboxyanhydride' formation, and hydrolysis permitted access to the Boc/Cbz- and Fmoc/Cbz-protected monophenacyl esters 11a and 11b, as well as to the fully orthogonally protected Fmoc/Boc monophenacyl ester 12 (Boc = (teri-butoxy)carbonyl, Fmoc = (9H-fluoren-9-ylmethoxy)carbonyl).