Douglas K. Hutchinson

Oxazolidinones: New antibacterial agents

The oxazolidinones are a new chemical class of synthetic antibacterial agents that are active orally or intravenously against multidrug-resistant Gram-positive bacteria. Their unique mechanism of action and activity against bacteria that pose therapeutic problems in hospital and community treatments make them promising candidates for antimicrobial agents.

Oxazolidinone antibacterial agents: development of the clinical candidates eperezolid and linezolid

Antimicrobial resistance is a significant nosocomial problem and is of increasing importance in community-acquired infections. One approach for overcoming resistance is the discovery and development of agents with new mechanisms of action. The oxazolidinones make up a relatively new class of antimicrobial agents which possess a unique mechanism of bacterial protein synthesis inhibition. Eperezolid and linezolid are two novel analogues that have demonstrated a variety of positive attributes. These agents inhibit many clinically-significant bacterial species both in vitro and in animal models of human infection. Furthermore they have oral bioavailability, and are well tolerated in humans at doses which produce plasma concentrations in excess of the levels predicted to be necessary for efficacy. In this review, we discuss the key information from the literature that supports the Phase II development of linezolid.

Identification of aryl dihydrouracil derivatives as palm initiation site inhibitors of HCV NS5B polymerase

Aryl dihydrouracil derivatives were identified from high throughput screening as potent inhibitors of HCV NS5B polymerase. The aryl dihydrouracil derivatives were shown to be non-competitive with respect to template RNA and elongation nucleotide substrates. They demonstrated genotype 1 specific activity towards HCV NS5B polymerases. Structure activity relationships and genotype specific activities of aryl dihydrouracil derivatives suggested that they bind to the palm initiation nucleotide pocket, a hypothesis which was confirmed by studies with polymerases containing mutations in various inhibitor binding sites. Therefore, aryl dihydrouracil derivatives represent a novel class of palm initiation site inhibitors of HCV NS5B polymerase.

Inhibitors of hepatitis C virus polymerase: synthesis and biological characterization of unsymmetrical dialkyl-hydroxynaphthalenoyl-benzothiadiazines.

The hepatitis C virus (HCV) NS5B polymerase is essential for viral replication and has been a prime target for drug discovery research. Our efforts directed toward the discovery of HCV polymerase inhibitors resulted in the identification of unsymmetrical dialkyl-hydroxynaphthalenoyl-benzothiadiazines 2 and 3. The most active compound displayed activity in genotypes 1a and 1b polymerase and replicon cell culture inhibition assays at subnanomolar and low nanomolar concentrations, respectively. It also displayed an excellent pharmacokinetic profile in rats, with a plasma elimination half-life after intravenous dosing of 4.5 h, oral bioavailability of 77%, and a peak liver concentration of 21.8 microg/mL.

Synthesis and biological characterization of B-ring amino analogues of potent benzothiadiazine hepatitis C virus polymerase inhibitors

Benzothiadiazine inhibitors of the HCV NS5B RNA-dependent RNA polymerase are an important class of non-nucleoside inhibitors that have received considerable attention in the search for novel HCV therapeutics. Research in our laboratories has identified a novel series of tetracyclic benzothiadiazine inhibitors of HCV polymerase bearing a benzylamino substituent on the B-ring. Compounds in this series exhibit low-nanomolar activities in both genotypes 1a and 1b polymerase inhibition assays and subgenomic replicon assays. Optimization of pharmacokinetic properties in rat led to compound 30, which has good oral bioavailability (F = 56%) and a favorable tissue distribution drug profile, with high liver to plasma ratios. Compound 30 is a potent inhibitor in replicon assays, with EC(50) values of 10 and 6 nM against genotypes 1a and 1b, respectively.

Hepatitis C NS5B polymerase inhibitors: 4,4-Dialkyl-1-hydroxy-3-oxo-3,4-dihydronaphthalene-3-yl benzothiadiazine derivatives.

4,4-Dialkyl-1-hydroxy-3-oxo-3.4-dihydronaphthalene-3-yl benzothiadiazine derivatives were synthesized and evaluated as inhibitors of genotypes 1a and 1b HCV NS5B polymerase. A number of these compounds exhibited potent activity against genotypes 1a and 1b HCV polymerase in both enzymatic and cell culture activities. A representative compound also showed favorable pharmacokinetics in the rat.

Design, Synthesis, and Evaluation of Novel Oxazolidinone Antibacterial Agents Active Against Multidrug-Resistant Bacteria

Throughout the human experience, diseases caused by pathogenic bacteria have exerted an enormous negative impact on society. Today, for example, approximately one third of the world’s population is infected with Mycobacterium tuberculosis and tuberculosis remains the leading cause of death in the world from infectious disease (Bloom, 1994). The emergence of effective antibacterial agents, from penicillin to more contemporary drugs, was initially thought to mark an end to the burden of microbial disease. However, subsequent events have illustrated the resiliency of bacteria to environmental pressures, including the threat of antibacterial agents.

Hepatitis C NS5B polymerase inhibitors: Functional equivalents for the benzothiadiazine moiety

A series of quinoline derivatives was synthesized as potential bioisosteric replacements for the benzothiadiazine moiety of earlier Hepatitis C NS5B polymerase inhibitors. Several of these compounds exhibited potent activity in enzymatic and replicon assays.

U-87947E, a protein quinolone antibacterial agent incorporating a bicyclo[1.1.1]pent-1-yl (BCP) subunit

Incorporation of a bicyclo[1.1.1]pent-1-yl group at the N-1 position of quinolone antibacterial agents affords compounds with potent activity. One of these analogs, U-87947E, exhibits enhanced activity relative to that of ciprofloxacin against gram-positive aerobic bacteria and anaerobic organisms. Time-kill kinetic studies reveal that U-87947E is exquisitely bactericidal against ciprofloxacin-resistant Staphylococcus aureus.

Aryl uracil inhibitors of hepatitis C virus NS5B polymerase: Synthesis and characterization of analogs with a fused 5,6-bicyclic ring motif

The synthesis and structure-activity relationships of a novel aryl uracil series which contains a fused 5,6-bicyclic ring unit for HCV NS5B inhibition is described. Several analogs display replicon cell culture potencies in the low nanomolar range along with excellent rat pharmacokinetic values.