The chemistry of nitro-compounds. Part I. Acid-catalysed ring-opening reactions of substituted o-nitrophenylethylene oxides involving participation by the nitro-group

Abstract

Ethereal hydrogen chloride converts trans-1-acetyl- and 1-benzoyl-2-(o-nitrophenyl)ethylene oxides (1c and a) in low yield into the corresponding 6-chloro-1,3-dihydroxyquinolin-4-ones (2a and c). In contrast, reaction of the cis-benzoyl epoxide (1b) or of the 1,1-diacylethylene oxides (1d and e) with ethereal hydrogen chloride affords high yields of the compounds (2a and c). In the presence of hydroquinone these reactions give the chlorine-free 1,3-dihydroxyquinolones (2b and d). The course and mechanism of the reactions are discussed.

Manganese dioxide oxidation of the 1-hydroxyquinolones (2a—d) and of the reduction products (3a and b) affords the hitherto unknown quinoline-3,4-quinones (7a—d) and (8a and b).