Oxidative Transformations of Minor Components of Nucleic Acids. An Anomalous Reaction Course of Oxidation of N6,N6-Dialkyladenosines and Related Compounds with m-Chloroperoxybenzoic Acid

Article abstract of DOI:10.1021/jo00244a010

Oxidation of N⁶-methyladenosine (1a) or the corresponding tribenzoate 1b with m-chloroperoxybenzoic acid gave N¹-oxides 2a and 2b whereas N⁶,N⁶-dimethyladenosine tribenzoate (3a) afforded 2',3',5'-tri-O-benzoylinosine (4a) and N⁶-methyl-N⁶-formyl derivative 5.The N⁶,N⁶-diethyladenosine 3b and piperidine derivative 3c yielded only 4a, but N⁶,N⁶-dibenzyl compound 3d was not oxidized.N,N-Dimethyl-2,4-dinitroaniline (6a) was oxidized with m-chloroperoxybenzoic acid to give N-methyl-N-formyl derivative 7a, N-methyl-2,4-dinitroaniline (8a), N-oxide 10a, and only traces of 2,4-dinitrophenol (9a).By contrast, 2-(dimethylamino)-5-nitropyridine (6b) afforded 5-nitro-2-pyridone (9b) and N-demethylated N¹-oxide 11. 2-(Dimethylamino)pyridine (6c) and 2-(methylamino)-5-nitropyridine (8b) gave the respective N²- and N¹-oxides 10c and 11.The reaction of 6-chloropurine nucleosides 15a and 15b with N,N-dimethylhydroxylamine gave inosine 4a or 4b accompanied by a smaller amount of 3a or 3e. 2,4-Dinitrofluorobenzene (16) afforded O-(2,4-dinitrophenyl)-N,N-dimethylhydroxylamine (17).Mass spectra of compounds 10a, 10c, and 17 provided evidence for Meisenheimer rearrangement and subsequent cyclic transformation.The N-oxide 10a and hydroxylamino derivative 17 gave 2,4-dinitrophenol (9a), and N²-oxide 10c afforded fragments belonging to 2-pyridone (9c).Compound 17 is thermally stable whereas N-oxide 10a yielded at 100 deg C a mixture of 8a, 8b, 9a, and 17.