Identification of potent and orally bioavailable nucleotide competing reverse transcriptase inhibitors: In vitro and in vivo optimization of a series of benzofurano[3,2-d]pyrimidin-2-one derived inhibitors

• Published in: Bioorganic & medicinal chemistry letters Vol. 23; no. 13; pp. 3967 - 3975
• Main Authors: Sturino, Claudio F., Bousquet, Yves, James, Clint A., DeRoy, Patrick, Duplessis, Martin, Edwards, Paul J., Halmos, Ted, Minville, Joannie, Morency, Louis, Morin, Sébastien, Thavonekham, Bounkham, Tremblay, Martin, Duan, Jianmin, Ribadeneira, Maria, Garneau, Michel, Pelletier, Alex, Tremblay, Sonia, Lamorte, Louie, Bethell, Richard, Cordingley, Michael G., Rajotte, Daniel, Simoneau, Bruno
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-07-2013
• Subjects: active sites; Administration, Oral; Animals; Antiviral Agents - administration & dosage; Antiviral Agents - chemistry; Antiviral Agents - pharmacology; Benzofuranopyrimidone; Benzofurans - chemistry; Benzofurans - pharmacology; bioavailability; Biological Availability; Caco-2 Cells; chemotypes; Dose-Response Relationship, Drug; enzyme-linked immunosorbent assay; HIV - drug effects; HIV Reverse Transcriptase - antagonists & inhibitors; HIV Reverse Transcriptase - metabolism; HIV-1; Human immunodeficiency virus; Humans; Microbial Sensitivity Tests; Models, Molecular; Molecular Structure; NcRTI; Nucleotide competing; permeability; pharmacokinetics; Pyrimidinones - administration & dosage; Pyrimidinones - chemistry; Pyrimidinones - pharmacology; Rats; Reverse transcriptase; Reverse Transcriptase Inhibitors - administration & dosage; Reverse Transcriptase Inhibitors - chemistry; Reverse Transcriptase Inhibitors - pharmacology; RNA-directed DNA polymerase; Structure-Activity Relationship; HIV-1; Reverse transcriptase; Benzofuranopyrimidone; Nucleotide competing; NcRTI; IGRNPARNLSUQKX-HOTGVXAUSA-N; UVOJGEJSFVVDCT-ROUUACIJSA-N
• ISSN: 0960-894X; 1464-3405
• DOI: 10.1016/j.bmcl.2013.04.043

Recently, a new class of HIV reverse transcriptase (HIV-RT) inhibitors has been reported. The novel mechanism of inhibition by this class involves competitive binding to the active site of the RT enzyme and has been termed Nucleotide-Competing Reverse Transcriptase Inhibitors (NcRTIs). In this publication we describe the optimization of a novel benzofurano[3,2-d]pyrimidin-2-one series of NcRTIs. The starting point for the current study was inhibitor 2, which had high biochemical and antiviral potency but only moderate permeability in a Caco-2 assay and high B-to-A efflux, resulting in moderate rat bioavailability and low Cmax. We present herein the results and strategies we employed to optimize both the potency as well as the permeability, metabolic stability and pharmacokinetic profile of this series. One of the key observations of the present study was the importance of shielding polar functionality, at least in the context of the current chemotype, to enhance permeability. These studies led to the identification of inhibitors 39 and 45, which display sub-nanomolar antiviral potency in a p24 ELISA assay with significantly reduced efflux ratios (ratios <1.5). These inhibitors also display excellent rat pharmacokinetic profiles with high bioavailabilities and low clearance.