Selektive Spaltung substituierter Phenylsulfenyl‐Schutzgruppen bei Peptidsynthesen

Abstract

The selective cleavage of the N‐sulphenyl protecting group from amino‐acids and peptides containing additional acid‐labile protecting residues has been investigated. Among various nucleophilic reagents tested for their ability to effect rapid and specific removal of the N‐sulphenyl groups, hydrogen cyanide, sulfurous acid and thioacetamide have been found to be particularly suitable. The application of this method to the solid phase synthesis of peptides is described and discussed.

Solid‐Phase Peptide Synthesis

“…Because of this reaction rare should be taken to avoid contamination of solvents with alcohols during the normal neutralization step. Hydrazine has also proved to be a valuable cleavage method (27,76,228,155) since the resulting peptide hydrazides can be converted to azides for further coupling reactions. Side-chain esters and amides are also reactive and should be avoided during the hydraziriolysis step.…”

“…The low yield in this reaction (about 35550%) was not a serious drawback because unreacted amino acid derivative could easily be recovered unchanged (140). The conversion is never complete even when a large excess of amino acid is used, but by prolonged treatment with an excess of triethylammonium acetate most of the remaining chloromethyl could be acetylated (129,76,40,20). The latter step is normally omitted, however, because the unreacted chloromethyl groups have not been found to interfere with the later steps in the synthesis.…”

Peptides With Affinity for Membranes

“…Such an approach could combine the advantages of the solid-phase and classical methods of peptide synthesis. Among the methods that have been explored for the preparation of protected segments on the solid phase are the use of anchoring bonds that are cleaved by acidolysis (93, 114, 11 5, 117), hydrazinolysis (17,59,80), alcoholysis (6)(7)(8), and photolysis (85,116). However, each of these procedures has inherent problems.…”

(Cholestanyloxycarbonyl)benzyl esters as peptide substituents: Conformational properties of fully protected oligo‐L‐lysines with C‐terminal (cholestanyloxycarbonyl)benzyl and benzyl ester moieties

“…For the standard extractions in the spray-column extractor according to the two-phase-purification method [2], all reaction solutions were diluted 50-100 fold with CH2CI,. Rcmoval of Nps groups was performed with Na,S,O, according to [33] or with NH4SCN/(2-methyl-l-indolyl)acetic acid according to [341, mainly in series A. Purification by column chroinatography on silica gel 60 was necessary for 11.4, IIIA, IIB and VIIIB.…”