New approaches to the preparation of azoxyfuroxans

A new convenient method for the synthesis of 4,4′-azoxyfuroxans by reductive condensation of 4-nitrofuroxans (4-nitro-1,2,5-oxadiazole 2-oxides) has been developed; the title compounds can also be synthesised by oxidation of 4-amino- and 4,4′-azofuroxans, and a general method for the synthesis of isomeric azofuroxans is suggested.