Cinnolines. Part II. Reaction with hydrogen peroxide and acetic acid

A number of new 4-alkyl- and 3,4-dialkyl-cinnolines have been prepared; they react with aqueous hydrogen peroxide in acetic acid to give the 1- and 2-oxides and the 1,2-dioxides. 4-Carboxy- and 4-methyl-3-nitrocinnolines give the corresponding 2- and 1-oxides respectively. The 4-alkyl- and 3,4-dialkyl-8-nitrocinnolines, in contrast, give the 8-nitro-cinnolin-4-ones. Under the same conditions, 4-methyl 8-nitroquinoline gives 2-amino-3-nitroacetophenone. Possible mechanisms of these and related reactions are discussed.