New Teixobactin Analogues with a Total Lactam Ring.

Teixobactin is a new antibiotic peptide with strong efficacy against several Gram-positive resistant bacteria, the structure of which is extremely difficult to obtain in the laboratory via multistep conventional synthesis. To face the increasing antibiotic resistant bacteria, it is fundamental to introduce new types of antibiotics with innovative mechanisms of action without resistance; thus, many scientists are studying and developing new methods to synthesize teixobactin analogues. In this work, seven Arg 10 -teixobactin analogues with a total lactam ring have been prepared via solid phase peptide synthesis. In order to obtain the total lactam ring, d-Thr 8 was replaced by (2 R ,3 S )-diamino-propionic acid. To verify their antimicrobial activity and efficacy, each analogue was tested with MIC against different resistant pathogens, showing an interesting activity for Nle 11 containing compounds.