SYNTHESIS OF TRIPEPTIDES CONTAINING HETEROCYCLIC alpha-AMINO ACIDS BY USING HETEROSPIROCYCLIC 3-AMINO-2H-AZIRINES

摘要

By using the 'azirine/oxazolone method', di- and tripeptides containing six-membered heterocyclic 4-amino-4-carboxylic acids with a piperidine, tetrahydropyran or tetrahydrothiopyran ring have been synthesized. It has been shown that the corresponding heterospirocyclic 3-(N-methyl-N-phenylamino)-2H-azirines are suitable synthons for these heterocyclic alpha-amino acids. As expected, the presence of these alpha,alpha-disubstituted alpha-amino acids stabilizes beta-turn conformations in the prepared tripeptides of type Z-Phe-Xaa-Val-OR.