Studies of peptide antibiotics. XLI. Syntheses of 6-L-valine-tyrocidine A and 7-L-ornithine-tyrocidine A.

Tyrocidine A (TA) is an antibiotic cyclic decapeptide with the sequence of cyclo (-L-Val1-L-Orn2-L-Leu3-D-Phe4-L-Pro5-L-Phe6-D-Phe7-L-Asn8-L-Gln9-L-Tyr10-). ...