Ferric nitrate-mediated synthesis of functionalized 1,2,3-benzotriazinones from 2-aminobenzamides and 2-nitrobenzamides <i>via</i> 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 <i>via</i> 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 <i>N</i>-aryl, <i>N</i>-alkyl, and substituted benzamides.