N-methylhydroxylamine hydrochloride → (4-tert-butoxycarbonyl-3-methyl-benzylidene)-N-methyl-nitrone

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-formyl-2-methyl-benzoic acid tert-butyl ester (Example I2) (1.57 g) in tetrahydrofuran/water (3:1) (20 ml) was added sodium acetate (0.67 g) and N-methylhydroxylamine hydrochloride (0.69 g). The reaction mixture was stirred at 50° C. for 15 hours. The reaction mixture was diluted with ethyl acetate and water. The phases were separated and the organic layer was washed with water, dried over sodium sulfate and concentrated. The residue was purified by column chromatography on silica gel (eluent: methanol/ethyl acetate 5:5) to give (4-tert-butoxycarbonyl-3-methyl-benzylidene)-N-methyl-nitrone (1.43 g) as yellow oil. 1H-NMR (CDCl3, 400 MHz): 8.10 (s, 1H), 8.02 (d, 1H), 7.85 (d, 1H), 7.35 (s, 1H), 3.90 (s, 3H), 2.60 (s, 3H).

Provenance & Evidence