Nidhi Arora

Design of annulated pyrazoles as inhibitors of HIV-1 reverse transcriptase

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are recommended components of preferred combination antiretroviral therapies used for the treatment of HIV. These regimens are extremely effective in suppressing virus replication. Structure-based optimization of diaryl ether inhibitors led to the discovery of a new series of pyrazolo[3,4-c]pyridazine NNRTIs that bind the reverse transcriptase enzyme of human immunodeficiency virus-1 (HIV-RT) in an expanded volume relative to most other inhibitors in this class.The binding mode maintains the beta13 and beta14 strands bearing Pro236 in a position similar to that in the unliganded reverse transcriptase structure, and the distribution of interactions creates the opportunity for substantial resilience to single point mutations. Several pyrazolopyridazine NNRTIs were found to be highly effective against wild-type and NNRTI-resistant viral strains in cell culture.

Cyclic amide bioisosterism: strategic application to the design and synthesis of HCV NS5B polymerase inhibitors.

Conformational modeling has been successfully applied to the design of cyclic bioisosteres used to replace a conformationally rigid amide bond in a series of thiophene carboxylate inhibitors of HCV NS5B polymerase. Select compounds were equipotent with the original amide series. Single-point mutant binding studies, in combination with inhibition structure-activity relationships, suggest this new series interacts at the Thumb-II domain of NS5B. Inhibitor binding at the Thumb-II site was ultimately confirmed by solving a crystal structure of 8b complexed with NS5B.

3-Amino-pyrazolo[3,4-d]pyrimidines as p38α kinase inhibitors: Design and development to a highly selective lead

Learnings from previous Roche p38-selective inhibitors were applied to a new fragment hit, which was optimized to a potent, exquisitely selective preclinical lead with a good pharmacokinetic profile.

Diphenyl ether non-nucleoside reverse transcriptase inhibitors with excellent potency against resistant mutant viruses and promising pharmacokinetic properties.

Non‐nucleoside reverse transcriptase inhibitors (NNRTIs) are part of the preferred treatment regimens for individuals infected with HIV. These NNRTI‐based regimens are efficacious, but the most popular NNRTIs have a low genetic barrier to resistance and have been associated with adverse events. There is therefore still a need for efficacious antiviral medicines that facilitate patient adherence and allow durable suppression of viral replication. As part of an extensive program targeted toward the discovery of NNRTIs that have favorable pharmacokinetic properties, good potency against NNRTI‐resistant viruses, and a high genetic barrier to drug resistance, we focused on the optimization of a series of diaryl ether NNRTIs. In the course of this effort, we employed molecular modeling to design a new set of NNRTIs that that are active against wild‐type HIV and key NNRTI‐resistant mutant viruses. The structure–activity relationships observed in this series of compounds provide insight into the structural features required for NNRTIs that inhibit the replication of a wide range of mutant viruses. Selected compounds have promising pharmacokinetic profiles.

Synthesis and biological activity of new pyridone diaryl ether non-nucleoside inhibitors of HIV-1 reverse transcriptase

New pyridone non-nucleoside reverse transcriptase inhibitors (NNRTIs) were prepared and several flexible routes to this class of inhibitor were identified. These NNRTIs were active inhibitors of the replication of wild-type and NNRTI-resistant HIV. Structure-based drug design was used to optimize the activity of the compounds against NNRTI-resistant mutants. The co-crystal structure of inhibitor 2b in the NNRTI binding pocket of HIV reverse transcriptase (HIVRT) is also described.