87691-28-9Relevant articles and documents
Simple Synthesis of cis-4-Hydroxy-L-proline and Derivatives Suitable for Use as Intermediates in Peptide Synthesis
Papaioannou, Dionissios,Stavropoulos, George,Karagiannis, Kostas,Francis, George W.,Brekke, Trond,Aksnes, Dagfinn W.
, p. 243 - 251 (2007/10/02)
An intramolecular Mitsunobu reaction in the presence of triphenylphosphine - diethyl azodicarboxylate (TPP-DEAD) resulted in the conversion of trans-4-hydroxy-N-trityl-L-proline to 5-triphenylmethyl-2-oxa-5-aza-bicycloheptan-3-one.This bicyclic lactone proved to be a key intermediate in the synthesis of cis-4-hydroxy-L-proline and derivatives thereof.TPP-DEAD-catalysed methanolysis of the key lactone gave the methyl ester of cis-4-hydroxy-N-trityl-L-proline, while ammonolysis in isopropyl alcohol provided the corresponding amide. p-Toluene-sulfonic acid treatmen t of the lactone, ester and amide led to detritylation and formation of the corresponding p-toluenesulfonates.Saponification of the key intermediate provided cis-4-hydroxy-N-trityl-L-proline which was first benzylated and then elaborated to the 1-hydroxybenzotriazolyl ester.This last ester and the three p-tolenesulfonates preparared above were utilised for the incorporation of cis-4-hydroxy-L-proline in the synthesis of model peptides.
