Microwave-Based Reaction Screening: Tandem Retro-Diels–Alder/Diels–Alder Cycloadditions of <i>o</i>-Quinol Dimers

We have accomplished a parallel screen of cycloaddition partners for <i>o</i>-quinols utilizing a plate-based microwave system. Microwave irradiation improves the efficiency of retro-Diels–Alder/Diels–Alder cascades of <i>o-</i>quinol dimers which generally proceed in a diastereoselective fashion. Computational studies indicate that asynchronous transition states are favored in Diels–Alder cycloadditions of <i>o</i>-quinols. Subsequent biological evaluation of a collection of cycloadducts has identified an inhibitor of activator protein-1 (AP-1), an oncogenic transcription factor

Exploiting Drug-Resistant Enzymes as Tools To Identify Thienopyrimidinone Inhibitors of Human Immunodeficiency Virus Reverse Transcriptase-Associated Ribonuclease H

The thienopyrimidinone 5,6-dimethyl-2-(4-nitrophenyl)­thieno­[2,3-<i>d</i>]­pyrimidin-4­(3<i>H</i>)-one (DNTP) occupies the interface between the p66 ribonuclease H (RNase H) domain and p51 thumb of human immunodeficiency virus reverse transcriptase (HIV RT), thereby inducing a conformational change incompatible with catalysis. Here, we combined biochemical characterization of 39 DNTP derivatives with antiviral testing of selected compounds. In addition to wild-type HIV-1 RT, derivatives were evaluated with rationally designed, p66/p51 heterodimers exhibiting high-level DNTP sensitivity or resistance. This strategy identified 3′,4′-dihydroxyphenyl (catechol) substituted thienopyrimidinones with submicromolar in vitro activity against both wild type HIV-1 RT and drug-resistant variants. Thermal shift analysis indicates that, in contrast to active site RNase H inhibitors, these thienopyrimidinones <i>destabilize</i> the enzyme, in some instances reducing the <i>T</i>_m by 5 °C. Importantly, catechol-containing thienopyrimidinones also inhibit HIV-1 replication in cells. Our data strengthen the case for allosteric inhibition of HIV RNase H activity, providing a platform for designing improved antagonists for use in combination antiviral therapy