Regioselective synthesis and anti-HIV activity of the novel 2- and 4-substituted pyrazolo[4,5-e][1,2,4]thiadiazines

The new regioisomer 7-methyl-pyrazolo[4,5-e][1,2,4]thiadiazine nucleus (5) was synthesized, and its novel mono-N2- or N4-substituted pyrazolo[4,5-e][1,2,4]thiadiazines (6, 7) were regioselectively prepared by deprotonation of N2 or/and N4 atoms with different molar ratio of NaH and alkyl halides. Anti-HIV-1 screening tests showed some compounds to be potent as HIV-1 non-nucleoside reverse transcriptase inhibitors (HIV-1 NNRTIs).