Reduction of Nitroalkenes to Oximes

Indium in Aqueous NH₄Cl [1]

To a solution of the b-nitrostyrene (3 mmol) in MeOH (10 ml) was added saturated ammonium chloride solution (10 ml) and indium powder (1 g). The reaction mixture was stirred under reflux for an appropriate time. After complete conversion, as indicated by TLC, the reaction mixture was diluted with water and extracted with ethyl acetate (2 x 15 ml). The combined organic layers were dried over anhydrous Na2SO4, concentrated in vacuo and the resulting product was purified by column chromatography on silica gel (Merck, 100-200 mesh, ethyl acetate-hexane, 2:8) gave oxime as E/Z isomers.

Substrate, Reaction time, Yield

• Phenyl-2-Nitropropene, 3h, 85%
• 3,4-Methylenedioxyphenyl-2-Nitropropene, 2h, 89%
• 3,4-Dimethoxyphenyl-2-Nitropropene, 3h, 76%
• 4-Methoxynitrostyrene, 3.5h, 88%
• 3,4-Methylenedioxynitrostyrene, 4.5h, 73%
• 3,4-Dimethoxynitrostyrene, 3h, 73%

[1] Synlett 1447–1449 (2000)