Mechanism of the Reaction of Nitriles with Alkaline Hydrogen Peroxide. Reactivity of Peroxycarboximidic Acid and Application to Superoxide Ion Reaction

Article abstract of DOI:10.1246/bcsj.54.793

Formation of peroxycarboximidic acid (1) is not rate-determining in the reaction of nitrile with alkaline hydrogen peroxide to form amide and oxygen; the yield of amide based on H2O2 varies from 20 to 60percent.When dimethyl sulfoxide (DMSO), a reactive substrate, is added, the rate is independent of and governed in turn by a rate-determining addition of HOO^- to nitrile.This reaction gives a reliable α-value of k_HOO-/k_HO-, which is 10000 for benzonitrile.A facile conversion of nitrile to amide may be achieved by the reaction in the presence of DMSO, unacco mpanied by side reactions such as the epoxyamide formation from α,β-unsaturated nitrile.Kinetics and product analysis suggest that a predominant reaction is not a non-radical oxidation of H2O2 with 1 but a radical decomposition of H2O2 which is induced by the homolysis of anion of 1 (1A).No singlet oxygen could be trapped chemically.The reaction of superoxide ion, O2^-., with acetonitrile is shown to be analogous to that of HOO^-; the decomposition of O2^-. is fast in the presence of MeCN and DMSO in benzene, affording acetamide and dimethyl sulfone.