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A novel liquid-phase method has been designed for the photolytic release of the attached peptides, directly as their C-terminal N-methylamides, under mild conditions in excellent yields and purity. The present approach provides fully side-chain protected peptide N-methylamides, useful for segment condensation and facilitate photo-controlled release of biologically active peptides for therapeutic applications.

Synthesis of a new photolabile polymeric support (NBHA-resin) and its application in solid-phase synthesis of fully protected and unprotected C-terminal peptide amides are described. Peptide amides were obtained in high yields due to the better photocleavage efficiency of NBHA-resin compared to o-nitrobenzylamino-resins.

1-Chloromethyl-2-nitro tetraethyleneglycol diacrylate (TTEGDA)-crosslinked polystyrene resin was prepared by nitration of chloromethyl (4%) TTEGDA-crosslinked polystyrene resin and used as a photosensitive solid support for the preparation of fully protected peptides. C-protected amino acid esters were attached to resin (1) using large excess of amino acid ester and equivalent amount of triethylamine (TEA). After estimation of first amino acid attachment, the stepwise synthesis of the peptides was carried out using the symmetric anhydride procedure. The fully protected peptides were cleaved from the support by photolysis. The crude product was purified on a silica gel column and characterised by amino acid analysis and tlc.

Zusammenfassung Die Synthese von 3-Nitro-4-aminomethylbenzoylpolyethylenglykol und seine Anwendung in der Flussigphasenpeptidsynthese wird beschrieben. Vollgeschutzte Peptide konnen durch Photolyse als C-terminale Amide quantitativ vom polymeren Trager abgespalten werden.