Ferric nitrate-mediated synthesis of functionalized 1,2,3-benzotriazinones from 2-aminobenzamides and 2-nitrobenzamides via nitrate reduction strategy

An efficient protocol for the synthesis of 1,2,3-benzotriazinones from 2-aminobenzamides has been developed using iron(III) nitrate and sodium metabisulfite via nitrate reduction, affording the desired products in good to excellent yields. In addition, the combination of iron nitrate and sodium dithionite enabled a complementary reductive diazotization of easily accessible 2-nitrobenzamides, furnishing 1,2,3-benzotriazinones in good yields. The developed method was further extended to the synthesis of 1,2,3,4-benzothiadiazine-1,1-dioxides and benzotriazoles. These methods are compatible with a broad range of N-aryl, N-alkyl, and substituted benzamides.