Preparation of the beta(3)-Homoselenocysteine derivatives Fmoc-beta(3)hSec(PMB)OH and Boc-beta(3)hSec(PMB)-OH for solution and solid-phase-peptide synthesis and selenoligation

作者：Floegel Oliver; Casi Giulio; Hilvert Donald; Seebach Dieter^*

来源：Helvetica Chimica Acta, 2007, 90(9): 1651-1666.

DOI：10.1002/hlca.200790171

The title compounds, 4 and 7, have been prepared from the corresponding a-amino acid derivative selenocystine (1) by the following sequence of steps: cleavage of the Se-Se bond with NaBH4, p- methoxybenzyl (PMB) protection of the SeH group, Fmoc or Boc protection at the N-atom and Arndt-Eistert homologation (Schemes I and 2). A beta(3)-heptapeptide 8 with an N-terminal beta(3)-hSec(PMB) residue was synthesized on Rink amide AM resin and deprotected ('in air') to give the corresponding diselenide 9, which, in turn, was coupled with a PI-tetrapeptide thiol ester 10 by a seleno-ligation. The product beta(3)-undecapeptide was identified as its diselenide and its mixed selenosulfide with thiophenol (Scheme 3). The differences between alpha- and beta-Sec derivatives are discussed.

• 出版日期2007