Isobutyl chloroformate → HCID 178446043, compound

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Reaction Steps

The cyclic dipeptide, cyclo-(Leu-His) is a known substance [F. Schneider, Hoppe-Seyler's Z. Phys. Chem. 338, 131 (1964)], which can be prepared according to the usual peptide synthesis. For example, condensation between N-benzyloxycarbonyl-(S)-leucine and methyl ester of (S)-histidine in the presence of isobutyl chloroformate is effected in accordance with the mixed acid anhydride process to obtain methyl ester of N-benzyloxycarbonyl-(S)-leucyl-(S)-histidine and then the ester is hydrogenolyzed in the presence of palladium-carbon, followed by cyclization under reflux in methanol.

Provenance & Evidence