Efficient Synthesis of Differentially Protected (S,S)-2,7- Diaminooctanedioic Acid, the Dicarba Analogue of Cystine
作者:Meinolf Lange、Peter M. Fischer
DOI:10.1002/(sici)1522-2675(19981111)81:11<2053::aid-hlca2053>3.0.co;2-4
日期:1998.11.11
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).