Structure-based discovery of pyrazolobenzothiazine derivatives as inhibitors of hepatitis C virus replication
Barreca, Maria Letizia × Manfroni, Giuseppe Leyssen, Pieter Winquist, Johan Kaushik-Basu, Neerja Paeshuyse, Jan Krishnan, Ramalingam Iraci, Nunzio Sabatini, Stefano Tabarrini, Oriana Basu, Amartya Danielson, U Helena Neyts, Johan Cecchetti, Violetta #
Journal of Medicinal Chemistry vol:56 issue:6 pages:2270-82
The NS5B RNA-dependent RNA polymerase is an attractive target for the development of novel and selective inhibitors of hepatitis C virus replication. To identify novel structural hits as anti-HCV agents, we performed structure-based virtual screening of our in-house library followed by rational drug design, organic synthesis, and biological testing. These studies led to the identification of pyrazolobenzothiazine scaffold as a suitable template for obtaining novel anti-HCV agents targeting the NS5B polymerase. The best compound of this series was the meta-fluoro-N-1-phenyl pyrazolobenzothiazine derivative 4a, which exhibited an EC50 = 3.6 μM, EC90 = 25.6 μM, and CC50 > 180 μM in the Huh 9-13 replicon system, thus providing a good starting point for further hit evolution.