The synthesis and biological activity of a novel cyclic β-sheet-type antimicrobial dehydropeptide based on gramicidin S (GS) is described. The GS analogue, containing two (Z)-(β-3-pyridyl)-α, β-dehydroalanine (Δ Z 3Pal) residues at the 4 and 4'positions (2), was synthesized by solution-phase methodologies using Boc-Leu-Δ Z 3Pal azlactone. Analogue 2 exhibited high antimicrobial activity against Gram-positive bacteria and had much lower ...
