Oximes Ponzio reaction

The Ponzio reaction provides a useful route to gem-dinitro compounds and involves treating oximes with a solution of nitrogen dioxide or its dimer in diethyl ether or a chlorinated solvent. The Ponzio reaction works best for aromatic oximes where the synthesis of many substituted aryldinitromethanes have been reported. Compound (56), an isomer of TNT, is formed from the reaction of dinitrogen tetroxide with the oxime of benzaldehyde (55) followed by mononitration of the aromatic ring with mixed acid. Yields are usually much lower for aliphatic aldoximes and ketoximes. " The parent carbonyl compound of the oxime is usually the major by-product in these reactions. 

The use of dinitrogen pentoxide in the Ponzio reaction for the oxidation-iutration of oximes to em-dinitro groups has been reported by Russian chemists. Millar and co-workers extensively investigated these reactions and reported the synthesis of 2,4,5,7,9,9-hexanitrofluorene (2), a thermally stable explosive with an oxygen balance better than TNT. Other energetic materials containing gem-dinitro functionality were synthesized from the oximes of acetophenone, 4-nitroacetophenone, a-nitroacetophenone and 2-hydroxyacetophenone. 

The oxidation of oximes by lead(IV) acetate, chlorine and other oxidants results in the formation of a-substituted nitroso compounds R R C(X)NO by attack of the oxidant at carbon. This is also the reaction commonly observ with dinitrogen tetroxide (the Ponzio reaction), the products being gem-... 

Some further monosubstituted furoxans which have been reported are either of very doubtful authenticity or have been discredited. The phenacyl derivatives of Harries and Tietz,462 formed by the nitrosation of /J-aryl-oc,/ -unsaturated oximes, have been shown to be pyrazolone di-JV-oxides 463 The degradation of Holleman s peroxide (29) by hydroxylamine and alkali was reported to form structure 218, or its 3-substituted isomer, by Boyer and Chang.29 It does, however, seem unlikely that a monosubstituted furoxan could withstand such reaction conditions. Decarboxylation of furoxandi-carboxylic acid has been suggested to provide the 4-monocarboxylic acid,464 but Ponzio and De Paolini465 have assigned a nitrile oxide structure to the product. 

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