Anti-HIV activity of new pyrazolobenzothiazine 5,5-dioxide-based acetohydrazides

A series of fifteen new 2-[3-(3-chlorophenyl)-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-4(2H)-yl]-N′-arylmethyleneacetohydrazides (5a–o) were synthesized and screened for their anti-HIV-1 and cytotoxicity activity. Out of fifteen pyrazolobenzothiazine-based hydrazones, thirteen were found to be active inhibitors of HIV with EC50 values <20 µM. Moreover, the cytotoxicity results showed that most of the compounds were toxic to PBM, CEM and Vero cell lines. This information could be used for structural modifications to acquire good candidates of HIV drugs.