N-(9-Xanthenyl)amino acid N-carboxyanhydrides in the solid-phase synthesis of a Lys-Lys-linked cyclic leucine-enkephalin.
The side-chain-protected heptapeptide Phe-Leu-Lys(F3Ac)-Lys(F3Ac)-Tyr(Cac)-Gly-Gly is assembled by stepwise chain elongation on a polystyrene resin, using inter alia N-(9-xanthenyl)-amino acid N-carboxyanhydrides. After HBr cleavage from the resin, cyclization via carbodiimide/N-hydroxysuccinimide is carried out in a yield of 24%. Cleavage of the 9-carbazolylcarbonyl group by hydrazinolysis, and alkaline hydrolysis of the trifluoroacetyl groups, affords cyclo (-Tyr-Gly-Gly-Phe-Leu-Lys-Lys-) in an over-all yield of 12%. The structure of the peptides is confirmed by mass spectrometry.
D004723:Endorphins / Q000138:chemical synthesis*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives*; D004745:Enkephalins / Q000138:chemical synthesis*; D006834:Hydrazines; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D008722:Methods; D014966:Xanthenes
D004723:Endorphins; D004745:Enkephalins; D006834:Hydrazines; D007202:Indicators and Reagents; D014966:Xanthenes; D004743:Enkephalin, Leucine; C031683:cyclic leucine enkephalin