Several fluorinated 1,3-diaminocyclopentanes, previously reported to be useful RNA structural probes, can be prepared in a diastereoselective manner from a single bicyclic hydrazine precursor, in 3 to 9 steps.

Antimicrobial peptides (AMPs) are considered as potential therapeutic sources of future antibiotics because of their broad-spectrum activities and alternative mechanisms of action compared to conventional antibiotics. Although AMPs present considerable advantages over conventional antibiotics, their clinical and commercial development still have some limitations, because of their potential toxicity, susceptibility to proteases, and high cost of production. To overcome these drawbacks, the use of peptides mimics is anticipated to avoid the proteolysis, while the identification of minimalist peptide sequences retaining antimicrobial activities could bring a solution for the cost issue. We describe here new polycationic -amino acids combining these two properties, that we used to design small dipeptides that appeared to be active against Gram-positive and Gram-negative bacteria, selective against prokaryotic versus mammalian cells, and highly stable in human plasma. Moreover, the in vivo data activity obtained in septic mice reveals that the bacterial killing effect allows the control of the infection and increases the survival rate of cecal ligature and puncture (CLP)-treated mice.

A strong revival of interest has been dedicated to peptides over the last few years, in different fields including drug discovery, biosensing and material sciences. The use of dynamic covalent chemistry has allowed the development of self‐adaptative peptides or peptidomimetics, responsive to their environment. The development of methods allowing the building, screening or deconvolution of libraries of peptides is a highly active research area and dynamic combinatorial chemistry represents an innovative and underexploited method in this field. This Review gives an overview of the use of dynamic covalent chemistry as a tool to produce peptides or peptidomimetics, with particular attention to applications in dynamic combinatorial chemistry.