66310-22-3Relevant articles and documents
The Reaction of Nitrosocarbonyl Compounds with 2,5-Disubstituted Furans. Synthesis of 1,4,2-Dioxazine and 1,4,2-Dioxazole Derivatives
Mackay, Donald,Dao, Le H.,Dust, Julian M.
, p. 2408 - 2416 (2007/10/02)
Oxidation of hydroxamic acids at room temperature in the presence of 2,5-dimethylfuran gives cis-1,4,2-dioxazolylbutenones (5), the structures of which have been confirmed by the synthesis of the dihydro-derivative (12) from the reaction of benzonitrile oxide with hexane-2,5-dione.If the oxidation is carried out at 0 deg C good yields of the unstable furodioxazines (7), the formal products of the addition of furan to the nitrosocarbonyl-arene or -alkane, can be isolated.Compounds (7) are the precursors to (5) and this isomerisation in the oxidation medium is essentially quantitative.It is probably catalysed by an unidentified component, since when pre-isolated (7) is heated the reaction is solvent-dependent and sometimes complex, the amounts of (5) formed being very variable.Nitrosocarbonylbenzene adds to the unsymmetrical compound 2-methyl-5-phenylfuran only at the 2,3-bond, giving the dioxazine (17) and thence the dioxazole (15) exclusively.Secondary amines add readily to the β-carbon of the enone group in (5) while tertiary amines, or more efficiently iodine, convert (5) into the trans-isomers (11). The retro-reaction of (5c) at 80 deg C to dimethylfuran and p-nitronitrosocarbonylbenzene has been demonstrated by trapping the latter, with 1,4-dimethyl-2,3-diphenylcyclopentadiene, as the adduct (21).
