93394-75-3Relevant academic research and scientific papers
Oxidative Deblocking of the 4-Methoxybenzyl Thioether Protecting Group: Application to the Directed Synthesis of Poly-cystinyl Peptides
Platen, Martin,Steckhan, Eberhard
, p. 1563 - 1576 (2007/10/02)
The 4-methoxybenzyl thioether protecting group is deblocked efficiently by oxidation with the homogeneous electron transfer agent tris(4-bromophenyl)ammoniumyl (2.+) leading to the disulfide in high yields.S-(4-methoxybenzyl)cysteine derivatives like 9 in this way can be transformed into the corresponding cystine derivatives like 10 in 90percent yield.Many N and carboxy protecting groups like the Boc and Z group and tert-butyl or benzyl ester functions are stable under the cleavage conditions.On the other hand the 4-methoxybenzyl thioether protecting group is totally unaffected by the conditions for oxidative deblocking of the S-trityl functions by either iodine or rhodanolysis.This opens up new opportunities for the directed synthesis of cystinyl peptides with more than one intra- or interchain disulfide bridge.Application of the new method to the synthesis of a cystine peptide with one intrachain S-S-bridge and a double-chain biscystinyl peptide is reported.
