EXPLORATORY-STUDY OF DIAZOKETONES AS SPIN TRAPS FOR NITRIC-OXIDE

2-Diazocycloheptanone traps nitric oxide to produce a mixture of radic als consisting mainly of the (Z)-iminoxyl radical together with minor amounts of the (E)-iminoxyl radical, a dialkyl aminoxyl and an acyl am inoxyl. Best EPR spectra have been obtained from solutions in tert-but ylbenzene which give signals lasting for several hours in the dark. Ni tric oxide in aqueous solution could be detected by means of the EPR s pectrum obtained on extraction with a tert-butylbenzene solution of th e spin trap. Nitric oxide release by isoamyl nitrite has been disclose d with the same spin trap although, under photolytic conditions, the s pectrum is dominated by the dialkyl aminoxyl. The main stable product from the reaction of nitric oxide with 2-diazocycloheptanone has been found to be cyclohexanecarboxylic acid. Satisfactory EPR spectra were not obtained from nitric oxide using 5-diazouracil as spin trap in aqu eous solution.