Discovery of Dap-3 Polymyxin Analogues for the Treatment of Multidrug-Resistant Gram-Negative Nosocomial Infections
摘要:
We report novel polymyxin analogues with improved antibacterial in vitro potency against polymprin resistant recent clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosa. In addition, a human renal cell in vitro assay (hRPTEC) was used to inform structure-toxicity relationships and further differentiate analogues. Replacement of the Dab-3 residue with a Dap-3 in combination with a relatively polar 6-oxo-1-phenyl-1,6-dihydropyridine-3-carbonyl side chain as a fatty acyl replacement yielded analogue 5x, which demonstrated an improved in vitro antimicrobial and renal cytotoxicity profiles relative to polymyxin B (PMB). However, in vivo PK/PD comparison of 5x and PMB in a murine neutropenic thigh model against P. aeruginosa strains with matched MICs showed that 5x was inferior to PMB in vivo, suggesting a lack of improved therapeutic index in spite of apparent in vitro advantages.
AbstractA chemoselective, palladium‐catalyzed, ligand‐directed ortho‐CH chlorination and acylation process has been developed, exhibiting high regioselectivity for 2‐arylpyridines bearing a meta‐substituent. Worthy of note is the fact that arylmethyl chlorides as new, readily available, and inexpensive reagents can selectively be utilized as chlorine or acyl sources.magnified image