3‐Nitro‐1,5‐naphthyridine and its 2‐substituted derivatives ( 1a‐f ) are dehydro‐methylaminated with a solution of potassium permanganate in liquid methylamine (LMA‐PP) to the corresponding 4‐methylamino‐3‐nitro‐1,5‐naphthyridines ( 3a‐e ). The intermediary 4‐methylamino σ adducts of 2‐R‐3‐nitro‐1,5‐naphthyridines (R ? H, NH2, Cl, NHCH3, OC2H5, OH) ( 2a‐f ) are detected by 1H nmr spectroscopy. The observed highly regioselective course of study reactions was confirmed by PM3 quantum chemical calculations of the reaction pathway. The calculations show satisfactory agreement between calculated and observed results. A convenient synthesis of 2‐hydroxy‐ and 4‐methylamino‐3‐nitro‐1,5‐naphthyridine are reported.
