Replacement of Imine Fragment in the Ring of 2,6-Disubstituted 1,4,3,5-Octathiadiazine-4,4-dioxides in Reaction with Cyano-containing Compounds

Reactions of 2,6-disubstituted 1,4,3,5-octathiadiazine-4,4-dioxides with cyano-containing compounds (nitriles, thiocyanates, N,N-disubstituted cyanamides) proceeding with replacement of imine fragment in dioxide by corresponding fragment of cyanide were investigated. The limits of the reaction were revealed determined by electronic effects of substituents R¹ and R² in dioxide and R³ in cyanide. Transimination occurred in dioxides with strong electron-withdrawing substituents R¹ (CCl₃, CBr₃, C₆F₅) and weak acceptor or donor substituents R²(4-NO₂C₆H₄, 4-ClC₆H₄, CH₃) under the action of compounds R³CN with cyano groups of relatively high nucleophilicity (R³ = 4-ClC₆H₄, C₆H₅, (CH₃)₂CHS, piperidino, morpholino, diethylamino), on the one hand, and with strong electron-withdrawing substituents R³ (CCl₃) on the other hand.