3-(2-Carbamoylvinyl)-4,5-dimethylpyrrole-2-carboxylic acids as ligands at the NMDA glycine-binding site: a study on the 2-carbamoylvinyl chain modification

6-Arylmethylidene Penicillin-Based Sulfone Inhibitors for Repurposing Antibiotic Efficiency in Priority Pathogens

The ability of 6-(aryl)methylidene penicillin-based sulfones 1-7 to repurpose β-lactam antibiotics activity with bacterial species that carry carbapenem-hydrolyzing class D β-lactamases (OXA-23, OXA-24/40 and OXA-48), as well as with class A (TEM-1, CTX-M-2) and class C (CMY-2, DHA-1) enzymes, is reported. The combinations imipenem/3 and imipenem/4 restored almost completely the antibiotic efficacy in OXA-23 and OXA-24/40 carbapenemase-producing A. baumannii strains (1 μg mL^-1) and also provided good results for OXA-48 carbapenemase-producing K. pneumoniae strains (4 μg mL^-1). Compounds 2-6 in combinations with ceftazidime and ampicillin were also efficient in restoring antibiotic efficacy in E. coli strains carrying class C (CMY-2 and DHA-1) and class A (TEM-1 and CTX-M-2) β-lactamase enzymes, respectively. Kinetic and inhibition studies with the OXA-24/40 enzyme, protein mass spectrometry analysis and docking studies allowed us to gain an insight into the inhibition mechanism and the experimentally observed differences between the ligands.

Synthesis and pharmacological properties of novel glycine antagonists

The NMDA receptor is an ionotropic receptor complex widely distributed in the central nervous system and its activation, particularly in hypoxic conditions such as stroke, traumatic head injury and hypoglycemia, results in a massive influx of calcium ions into the post-synaptic neurones, leading to cell death through the activation of several neurotoxic cascades. The NMDA receptor is a unique ionotropic receptor complex because its activation requires the simultaneous binding of glutamate and glycine and selective antagonists at the glycine binding site are endowed with a better side-effect profile than competitive NMDA antagonists. Then, considerable efforts have been devoted to find potent and selective ligands, resulting in the identification of several classes of glycine antagonists. The research at Glaxo Wellcome has been aimed at the identification of novel in vivo active glycine antagonists, and led to the synthesis and pharmacological characterization of a number of novel, potent and systemically active compounds belonging to different chemical classes.