A series of novel 2,4‐disubstituted 7‐methyl‐1,1,3‐trioxo‐2,4‐dihydro‐pyrazolo[4,5‐e] [1,2,4]thiadiazines (PTDs) was synthesized, structurally confirmed by spectral analysis, and evaluated for their anti‐HIV activities by inhibition of HIV‐induced cytopathogenicity in MT‐4 cell culture. The results showed that some compounds exhibited inhibitory activity specifically against HIV‐2 replication. The