SYNTHESIS OF 1,2,4-OXADIAZOLE-DERIVED, 1,3,4-OXADIAZOLE-DERIVED, AND 1,2,4-TRIAZOLE-DERIVED DIPEPTIDOMIMETICS

Three series of heterocyclic dipeptidomimetics have been synthesized. The compounds were designed as amino acid-glycine mimetics containing 1,2,4-oxadiazole, 1,3,4-oxadiazole, and 1,2,4-triazole ring systems, u seful as building blocks in the synthesis of modified peptides. The he terocyclic moieties were chosen according to their geometrical, electr ostatical, and hydrogen bonding properties together with the synthetic accessibility. The syntheses started with Boc-protected L-amino acids (Ala, Gly, Asp, Phe, Ser, Arg, Cys, and Pro), and the reaction condit ions were chosen to allow for the formation of products with high enan tiopurity. The enantiomeric excess was determined by HPLC using chiral stationary phases.