Exploring the reactivity of bicyclic α-iminophosphonates to access new imidazoline I receptor ligands.

Recent studies pointed out the modulation of imidazoline I receptors (I-IR) by selective ligands as a putative strategy to face neurodegenerative diseases. Foregoing the classical 2-imidazoline/imidazole-containing I-IR ligands, we report a family of bicyclic α-iminophosphonates endowed with high affinity and selectivity upon I-IR and we advanced a representative compound B06 in preclinical phases. In this paper, we describe the synthetic possibilities of bicyclic α-iminophosphonates by exploring its ambivalent reactivity, leading to unprecedented molecules that showed promising activities as I-IR ligands in human brain tissues and good BBB permeation capabilities.

Native Chemical Ligation via N-Acylurea Thioester Surrogates Obtained by Fmoc Solid-Phase Peptide Synthesis.

Native chemical ligation (NCL) enables the direct chemical synthesis and semisynthesis of proteins of different sizes and compositions, streamlining the access to proteins containing posttranslational modifications (PTMs). NCL assembles peptide fragments through the chemoselective reaction of a C-terminal α-thioester peptide, prepared either by chemical synthesis or via intein-splicing technology, and a recombinant or synthetic peptide containing an N-terminal Cys. Whereas the generation of C-terminal α-thioester proteins can be achieved via the recombinant fusion of the sequence of interest to an intein domain, chemical methods can also be used for synthetically accessible proteins.

Peptide Ligations by Using Aryloxycarbonyl-o-methylaminoanilides: Chemical Synthesis of Palmitoylated Sonic Hedgehog.

A simple procedure for C-terminal activation of peptides in solution and its application in native chemical ligation and protein synthesis is described. This method involves a mild thioesterification based on the conversion of an aryloxy-o-methylaminoanilide to thioester under aqueous conditions and in situ ligation with an N-terminal cysteine peptide. The versatility is shown in pH-controlled sequential ligations.