Synthese substituierter 2-Aminochinolin-1-oxide durch reduktive Cyclisierung substituierter 3-(2-Nitrophenyl)acrylnitrile
摘要:
An approach to the class of 2-aminoquinoline-1-oxides is given based on reductive cyclization of appropriate substituted 3-(2-nitrophenyl)acrylonitriles. Thus, 2-nitrobenzylidene compounds 1a - d have been reductively cyclized by H-2/PtO2 or H-2/Pd-C under normal conditions to form N-oxides 2a - d. H-1-NMR data show that 1d has to be regarded as ethyl(Z)-2-cyano-3-hydroxy-3-(2-nitrophenyl)acrylate.The analogous (2-nitrobenzoyl)acetonitrile 3, however, did not cyclize under the same conditions, but yielded anthraniloylacetonitrile 4. The results are discussed in comparison with the reaction behaviour of structural related nitronitriles under comparable conditions. A short survey of reactions leading to heterocyclic N-oxides by reductive cyclization of nitro compounds is given.