Scaffold hopping and optimisation of 3’,4’-dihydroxyphenyl- containing thienopyrimidinones: synthesis of quinazolinone derivatives as novel allosteric inhibitors of HIV-1 reverse transcriptase-associated ribonuclease H

• Main Authors: Graziella Tocco, Francesca Esposito, Pierluigi Caboni, Antonio Laus, John A. Beutler, Jennifer A. Wilson, Angela Corona, Stuart F. J. Le Grice, Enzo Tramontano
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2020-01-01
• Series: Journal of Enzyme Inhibition and Medicinal Chemistry
• Subjects: bioisosters; rnase h allosteric inhibitors; hiv-1 virus; rnase h; integrase
• Online Access: http://dx.doi.org/10.1080/14756366.2020.1835884
• ISSN: 1475-6366; 1475-6374

Bioisosteric replacement and scaffold hopping are powerful strategies in drug design useful for rationally modifying a hit compound towards novel lead therapeutic agents. Recently, we reported a series of thienopyrimidinones that compromise dynamics at the p66/p51 HIV-1 reverse transcriptase (RT)-associated Ribonuclease H (RNase H) dimer interface, thereby allosterically interrupting catalysis by altering the active site geometry. Although they exhibited good submicromolar activity, the isosteric replacement of the thiophene ring, a potential toxicophore, is warranted. Thus, in this article, the most active 2-(3,4-dihydroxyphenyl)-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H)-one 1 was selected as the hit scaffold and several isosteric substitutions of the thiophene ring were performed. A novel series of highly active RNase H allosteric quinazolinone inhibitors was thus obtained. To determine their target selectivity, they were tested against RT-associated RNA-dependent DNA polymerase (RDDP) and integrase (IN). Interestingly, none of the compounds were particularly active on (RDDP) but many displayed micromolar to submicromolar activity against IN.