Synthesis of Tetranitrotoluenes

New synthetic routes to the three isomeric tetranitrotoluenes 1-3 are described, including the previously unreported 2,3,4,5-tetranitrotoluene (1). Methods include peroxydisulfuric acid oxidation of trinitrotoluidines and hypophosphorous acid reduction of diazonium salts derived from tetranitrotoluidines. Synthesis of selected trinitrotoluidine precursors is also discussed