Chloro-, dichloro-, and chloromethyl-furoxan have been prepared by dehydrogenation of the corresponding glyoximes. anti-Chloromethylglyoxime reacts with nitrogen dioxide to give chlorooximinoacetone and 2,2-dinitropropiohydroxamoyl chloride in addition to the furoxan.On dehydrochlorination with bicarbonate 2,2-dinitropropiohydroxamoyl chloride is converted to 2,2-dinitropropionitrile oxide which dimerizes spontaneously. The properties, reactions, and structures of these compounds are discussed.
THE only known chlorofuroxan, dichlorofuroxan, has been prepared by chlorination of mercury fulminate" or sodium fulminate" and by dehydrochlorination of phosgene oxime.s-4 The yields in most of these reactions were poor and the products were difficult to purify. Satisfactory analyses were reported only in one paper," the identity of the compound being based on its boiling point. Evidence for the assigned structure of dichlorofuroxan was derived from its reactions with diethylamine and aniline-which cause reductive cleavage of the ring system and displacement of the halogens to give amidoximes.
It has been found now that chlorofuroxans can be prepared in good yield and satisfactory purity by dehydrogenation of the corresponding glyoximes with nitric acid or with nitrogen dioxide, depending on the compound. Disubstituted glyoximes, which have an anti-structure and s-trans conformation (1, Rand R' = Me or CI), 5 are converted in this fashion to furoxans (IT) as the R", ,1NOH