- Peptide coupling of unprotected amino acids through in situ p-nitrophenyl ester formation
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Several series of dipeptides and tripeptides were prepared via an activation-coupling method involving the in situ formation of a p-nitrophenyl ester of an (N-protected) amino acid, followed by coupling with an unprotected amino acid in partially aqueous solutions. The resulting peptide is easily isolated by precipitation. In general, the yields obtained are good to excellent and racemization is minimal. This method is particularly advantageous with respect to its simplicity and lack of obligatory side chain protection/deprotection steps.
- Gagnon, Paul,Huang, Xicai,Therrien, Eric,Keillor, Jeffrey W.
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p. 7717 - 7719
(2007/10/03)
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- Synthesis of a proposed antigenic hexapeptide from Escherichia coli K88 protein fimbriae.
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The hexapeptide Boc-Asp-Asp-Tyr-Arg-Gln-Lys-OMe is assembled by stepwise synthesis in solution with an overall yield of 44%. N alpha-boc-amino acids, protected with benzyl or benzyloxycarbonyl groups in the side-chains, are coupled as active estes of 1-hydroxybenzotriazole in mixtures of dichloromethane and N,N-dimethylformamide. N alpha-deprotection is accomplished with trifluoroacetic acid. Finally, hydrogenation with palladium on charcoal and ammonium formate produces the pure hexapeptide. A new one-pot synthesis of Boc-Arg(Z2) is described, and the use of this derivative in peptide coupling is studied. The synthetic peptide was coupled to BSA and used in direct immunication of rabbits.
- Meldal,Kindtler
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p. 235 - 241
(2007/10/02)
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