Collect. Czech. Chem. Commun. 1980, 45, 3546-3556

1,3-dipolar cycloaddition of C-benzoyl-N-phenylnitrone with furan derivatives. Anomalous dehydrogenation of cycloadducts with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

Lubor Fišeraa, Ján Leškob, Miloslava Dandárováa and Jaroslav Kováča

a Department of Organic Chemistry
b Laboratory of Mass Spectrometry, Slovak Institute of Technology, 880 37 Bratislava


C-Benzoyl-N-phenylnitrone reacted with 2-R-substituted (R = phenyl, CH2OH, CH2OCOCH3, CH2SH) furan derivatives at 55 °C by a 1,3-dipolar cycloaddition reaction to the unsubstituted furan double bond to give mono- and bisadducts. 2,5-Dimethylfuran afforded monoadduct only. Dehydrogenations of monoadducts of 5-R-2-phenyl-3-benzoyl-3a,6a-dihydrofuro[3,2-c]isoxazolines with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone proceeded anomalously at 60 °C: dehydrogenation followed by electrocyclic opening afforded the corresponding ketonitrones. This method of dehydrogenation offers a new preparation of nitrones and further exemplifies the exploitation of products of 1,3-dipolar cycloadditions for synthetic purposes.