ABSTRACT
Conformationally constrained tetracyclic fluoroquinolones (FQs) were synthesized and profiled for their microbiological spectrum. The installation of a seven-membered ring between the pyrrolidine substituents and the C8 position on the FQ core scaffold resulted in a remarkable enhancement of microbiological potency toward both Gram-positive and Gram-negative bacteria. Focused optimization of seven-membered ring composition, stereochemistry, and amine placement led to the discovery of the two lead compounds that were selected for further progression.
Subject(s)
Fluoroquinolones/chemical synthesis , Fluoroquinolones/pharmacology , Tetracyclines/chemical synthesis , Tetracyclines/pharmacology , Acinetobacter baumannii/drug effects , Microbial Sensitivity Tests , Molecular Structure , Pseudomonas aeruginosa/drug effects , Structure-Activity RelationshipABSTRACT
A series of oxadiazolone bioisosteres of pregabalin 1 and gabapentin 2 were prepared, and several were found to exhibit similar potency for the alpha(2)-delta subunit of voltage-gated calcium channels. Oxadiazolone 9 derived from 2 achieved low brain uptake but was nevertheless active in models of osteoarthritis. The high clearance associated with compound 9 was postulated to be a consequence of efflux by OAT and/or OCT, and was attenuated on co-administration with cimetidine or probenecid.
Subject(s)
Amines , Cyclohexanecarboxylic Acids , Osteoarthritis/drug therapy , Oxadiazoles/chemistry , Oxadiazoles/therapeutic use , gamma-Aminobutyric Acid/analogs & derivatives , Animals , Brain/metabolism , Drug Interactions , Drug Therapy, Combination , Gabapentin , Octamer Transcription Factors , Organic Anion Transporters , Oxadiazoles/pharmacology , Pregabalin , RatsABSTRACT
Pregabalin exhibits robust activity in preclinical assays indicative of potential antiepileptic, anxiolytic, and antihyperalgesic clinical efficacy. It binds with high affinity to the alpha(2)-delta subunit of voltage-gated calcium channels and is a substrate of the system L neutral amino acid transporter. A series of pregabalin analogues were prepared and evaluated for their alpha(2)-delta binding affinity as demonstrated by their ability to inhibit binding of [(3)H]gabapentin to pig brain membranes and for their potency to inhibit the uptake of [(3)H]leucine into CHO cells, a measure of their ability to compete with the endogenous substrate at the system L transporter. Compounds were also assessed in vivo for their ability to promote anxiolytic, analgesic, and anticonvulsant actions. These studies suggest that distinct structure activity relationships exist for alpha(2)-delta binding and system L transport inhibition. However, both interactions appear to play an important role in the in vivo profile of these compounds.