Synthesis of the very acid-sensitive Fmoc-Cys(Mmt)-OH and its application in solid-phase peptide synthesis.
S-4-methoxytrityl cysteine was synthesized and converted into the corresponding Fmoc-Cys(Mmt)-OH by its reaction with Fmoc-OSu. As compared to the corresponding Fmoc-Cys(Trt)-OH, the S-Mmt-function was found to be considerably more acid labile. Quantitative S-Mmt-removal occurs selectively in the presence of groups of the tert butyl type and S-Trt by treatment with 0.5-1.0% TFA. The new derivative was successfully utilized in the SPPS of Tyr1-somatostatin on 2-chlorotrityl resin. In this synthesis groups of the Trt-type were exclusively used for amino acid side-chain protection. Quantitative cleavage from the resin and complete deprotection was performed by treatment with 3% TFA in DCM-TES (95:5) for 30 min at RT. We observed no reduction of tryptophan under these conditions.
Barlos
K
K
Department of Chemistry, University of Patras, Greece.
Gatos
D
D
Hatzi
O
O
Koch
N
N
Koutsogianni
S
S
D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D004121:Dimethyl Sulfoxide; D005449:Fluorenes / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D013004:Somatostatin / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D014269:Trifluoroacetic Acid
C103143:9-fluorenylmethoxycarbonyl-S-(4-methoxytrityl)cysteine; D005449:Fluorenes; D009842:Oligopeptides; D013004:Somatostatin; C012088:somatostatin, N-Tyr(1)-; D014269:Trifluoroacetic Acid; D003545:Cysteine; D004121:Dimethyl Sulfoxide