Leu-L-Try-NHCHzCHzOH and HCO-L-Ileu-Gly-... were proposed for valine-and isoleucine- gramicidin A. 2 This paper describes the synthesis of these two formyl decapentapeptide ethanolamides and the comparison of their properties with those of the natural antibiotics. No particular difficulties were expected in the synthesis of these linear peptides since the building stones are neutral amino acids. However, the acid sensitivity of tryptophan put ...