Methylamination of some 3,6-dinitro-1,8-naphthyridines with liquid methylamine - potassium permanganate

3,6-Dinitro-1,8-naphthyridine and its 2-substituted derivatives are dehydro -methylaminated with the solution of potassium permanganate in liquid methy lamine (LMA-PP) to the corresponding mono- or mono- and bis(methylamino)-3, 6-dinitro-1,8-naphthyridines. In the case of 2-chloro- and 2-methoxy-3,6-di nitro-1,8-naphthyridine the replacement of chloro and methoxy substituents by the NHCH3 group occurs as well. Quantum-chemical calculations indicate t he reactions to be controlled by the interaction of the frontal molecular o rbitals (FMO) of the reagents. Moreover the heats of formation of intermedi ary methylamino-sigma-adducts and transition states are calculated for the reaction studied. The calculations show satisfactory agreement between calc ulated and observed results. A convenient synthesis of some 2-substituted-3 ,6-dinitro-1,8-naphthyridines is reported.