LAUSR

Oxidative dehydrogenation of 2-bromo-4-methylaniline with manganese(iv) oxide leads to the formation of (E)-1,2-bis(2-bromo-4-methylphenyl)diazene (1). The reaction of 1 with hydrazine hydrate gives the reduction product, 1,2-bis(2-bromo-4-methylphenyl)hydrazine (2). Compound 2 sequentially treated with methyllithium and two equivalents of (Et2N)2PCl in diethyl ether is converted to the diazadiphosphinine derivative. The reaction includes the following steps: 1) the phosphorylation of the nitrogen atom in the dilithium salt of hydrazo derivative 2, 2) the migratory insertion of (Et2N)2P group into the N–N bond, 3) phosphorylation of the second nitrogen atom, 4) arylation of the phosphorus in the (Et2N)2P group.