Synthesis and biological evaluation of pyridazine derivatives as novel HIV-1 NNRTIs.

In continuation of our efforts toward identification and optimization for novel non-nucleoside reverse transcriptase inhibitors (NNRTIs) project, we have employed a structure-based bioisosterism strategy, with which, a new series of diarylpyridazine (DAPD) derivatives were synthesized and evaluated for their anti-HIV-1 (human immunodeficiency virus type 1) activity. Most of the title compounds displayed excellent anti-HIV-1 activitiy at submicromolar concentrations ranged from 34nM to 5.08μM. The most promising compound 8g inhibited HIV-1 IIIB in MT-4 cells with low EC(50) value (0.034μM), which was higher than the reference drugs nevirapine and delavirdine. The structure activity relationships (SARs) were discussed and rationalized by docking simulations.