Search

Aromatic furazan has numerous pharmacologic and industrial applications. As part of our work on aromatic furazan chemistry and biochemistry, benzofurazan N-oxides, on irradiation using a high-pressure mercury lamp with a Pyrex filter in acetonitrile containing a little water, afforded 1H-azepine-2,7-dione. Mechanistic studies on the photoreaction using a low-pressure mercury lamp and photosensitizer suggest that photosensitized formation of 1H-azepine-2,7-dione with the aromatic hydrocarbon may be carried out by reabsorption of fluorescence. Quinoxaline 1,4-dioxide, phenazine 5,10-dioxide, and pyrido[2,3-b]pyrazine derivatives were synthesized from the corresponding aromatic or heteroaromatic furazan N-oxides by silica gel or molecular sieves under solvent-free conditions using microwave irradiation. The toxicities of some benzofurazans were examined on Escherichia coli; these may due to their reduction within the E. coli cell and their reoxidization by molecular dioxygen to form superoxide and hydrogen peroxide. The formation of 4,7-dicyanobenzofurazan anion radical in the E. coli cell suspension-4,7-dicyanobenzofurazan-glucose system in the absence of O 2 was followed by ESR spectroscopy. 4,7-Dimethylbenzofurazan was transformed by 1 O 2 produced by irradiation of C 60 into 4,7-dimethylbenzofurazan 4,7-endoperoxide. The endoperoxide decomposed back to 4,7-dimethylbenzofurazan at room temperature. 4,7-Dimethylbenzofurazan was transformed by irradiation with the third harmonic of a Quanta-Ray Nd:YAG laser (355 nm) into (2Z,4Z)-2,5-dimethylhexa-2,4-dienedinitrile monoxide. Irradiation of 4,7-dimethylbenzofurazan yielded a photoproduct with a quantum yield 0.48 and chemical yield 99%.

Twelve purines oxidized with 4,5-dimethyl-o-phenylenediamine (DMPD) was found to react with N-bromosuccinimide (NBS) to give fluorescent derivatives. In this paper, the identification of oxidation and fluorescent products have been described. In compliance with the substituent on purine skelton, three alloxans were obtained from twelve purines after oxidation by using NBS. The three alloxans reacted with DMPD to form two quinoxalines and an alloxazine, all of which being fluorescent.