N,N -Dialkyl- N′ -Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XV. Some Unexpected Reactions with Anilines

N,N-Dimethyl-N′-chlorosulfonyl chloroformamidine 1a underwent reactions with various anilines. In addition to the benzo[e][1,2,4]thiadiazine dioxides 8, from 1,3-NCC bis-nucleophilic substitution and bis-anilino adducts 9, some unexpected products were formed, particularly when sterically hindered or electron-poor anilines were used. In these cases, products such as the [1,3,2,4,6]dithiatriazine 1,1,3,3-tetraoxides 17 and, on occasion, N,N,5-trimethyl-4-(arylimino)-4,5-dihydro-[1,3,5]triazin-2-amines 14 were produced in significant yields. Reaction of dichloride 1a with 3-bromoaniline afforded the unusual eight-membered-ring product 2,6-bis(3-bromophenyl)-3,7-bis(dimethylamino)-2H,6H-[1,5,2,4,6,8]dithiatetrazocine 1,1,5,5-tetraoxide 28, in addition to the dithiatriazine tetraoxide 17k. These uncommon heterocyclic structures are of interest for bioactive molecule discovery screening programs.