ABSTRACT
Clostridium difficile (C. difficile) is a Gram positive, anaerobic bacterium that infects the lumen of the large intestine and produces toxins. This results in a range of syndromes from mild diarrhea to severe toxic megacolon and death. Alarmingly, the prevalence and severity of C. difficile infection are increasing; thus, associated morbidity and mortality rates are rising. 4-Aminothiazolyl analogues of the antibiotic natural product GE2270 A (1) were designed, synthesized, and optimized for the treatment of C. difficile infection. The medicinal chemistry effort focused on enhancing aqueous solubility relative to that of the natural product and previous development candidates (2, 3) and improving antibacterial activity. Structure-activity relationships, cocrystallographic interactions, pharmacokinetics, and efficacy in animal models of infection were characterized. These studies identified a series of dicarboxylic acid derivatives, which enhanced solubility/efficacy profile by several orders of magnitude compared to previously studied compounds and led to the selection of LFF571 (4) as an investigational new drug for treating C. difficile infection.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Clostridioides difficile/drug effects , Enterocolitis, Pseudomembranous/drug therapy , Thiazoles/chemical synthesis , Animals , Anti-Bacterial Agents/pharmacokinetics , Anti-Bacterial Agents/pharmacology , Cricetinae , Crystallography, X-Ray , Enterococcus/drug effects , Escherichia coli Proteins/antagonists & inhibitors , Escherichia coli Proteins/chemistry , Female , Male , Mesocricetus , Mice , Microbial Sensitivity Tests , Models, Molecular , Molecular Structure , Peptide Elongation Factor Tu/antagonists & inhibitors , Peptide Elongation Factor Tu/chemistry , Rats , Rats, Sprague-Dawley , Solubility , Staphylococcus aureus/drug effects , Streptococcus pyogenes/drug effects , Structure-Activity Relationship , Thiazoles/pharmacokinetics , WaterABSTRACT
4-Aminothiazolyl analogues of the antibiotic natural product GE2270 A (1) were designed, synthesized, and optimized for their activity against Gram positive bacterial infections. Optimization efforts focused on improving the physicochemical properties (e.g., aqueous solubility and chemical stability) of the 4-aminothiazolyl natural product template while improving the in vitro and in vivo antibacterial activity. Structure-activity relationships were defined, and the solubility and efficacy profiles were improved over those of previous analogues and 1. These studies identified novel, potent, soluble, and efficacious elongation factor-Tu inhibitors, which bear cycloalkylcarboxylic acid side chains, and culminated in the selection of development candidates amide 48 and urethane 58.
