SYNTHESES AND ANTIBACTERIAL ACTIVITIES OF GRAMICIDIN-S ANALOGS CONTAINING L-ORNITHINE IN-PLACE OF L-VALINE

A gramicidin S analog ([Orn(1,1')]GS.4HCl) containing L-ornithine in p lace of L-valine at the 1,1' positions was synthesized by the conventi onal solution method in order to examine whether this analog had antib acterial activity toward Gram-negative bacteria. In the synthesis of [ Orn(1,1')]GS.4HCl, two intermediate analogs ([Orn(1,1'), Orn(For)(2,2' )]GS.2HCl and [Orn(Z)(1,1')]GS.2HCl) were obtained. [Orn(1,1')]GS.4HCl and [Orn(1,1'), Orn(For)(2,2')]GS.2HCl showed no activity toward eith er Gram-negative or Gram-positive bacteria, whereas [Orn(Z)(1,1')]GS.2 HCl showed appreciable activity toward only Gram-positive bacteria.