5934-88-3

We report a photochemical method for the chemoselective radical functionalization of tryptophan (Trp)-containing peptides. The method exploits the photoactivity of an electron donor-acceptor complex generated between the tryptophan unit and pyridinium sal

A simple protocol for the regioselective N-arylation of the indole side chain of tryptophan using triarylbismuth reagents as the arylating agent is reported. The reaction is catalyzed by copper(II) acetate, and operates in the presence of triethylamine or

A mild, practical, and simple procedure for peptide-bond formation is reported. Instead of activation of the carboxylic acid functionality, the reaction involves an unprecedented use of activated α-aminoesters. The method provides a straightforward entry to dipeptides and was effective when a sensitive cysteine residue was used, as no epimerization was detected in this case. The applicability of this method to iterative peptide synthesis was illustrated by the synthesis of a model tetrapeptide in the challenging reverse N→C direction. How to advance by going into reverse: In a mild and practical procedure for peptide-bond formation, free α-aminoesters were activated by treatment with N,N′-carbonyldiimidazole, instead of activating the carboxylic acid functionality (see scheme). The method provided a straightforward route to dipeptides, and its applicability to iterative peptide synthesis was illustrated by the synthesis of a tetrapeptide in the challenging reverse N→C direction.

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Several 3-O--hydroxy-2-phenylindenones were obtained and used in the synthesis of peptides.Synthesis of Leu-enkephalin was carried out.