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

HRID 874212Notes

Reaction equation

[C:1]([O:5][C:6](=[O:16])[C:7]1[CH:12]=[CH:11][C:10]([CH:13]=O)=[CH:9][C:8]=1[CH3:15])([CH3:4])([CH3:3])[CH3:2].[C:17]([O-])(=O)C.[Na+].Cl.[CH3:23][NH:24][OH:25]>O1CCCC1.O.C(OCC)(=O)C.O>[C:1]([O:5][C:6]([C:7]1[CH:12]=[CH:11][C:10]([CH:13]=[C:23]=[N+:24]([CH3:17])[O-:25])=[CH:9][C:8]=1[CH3:15])=[O:16])([CH3:4])([CH3:3])[CH3:2]

Participants

Conditions

Temperature: 50 °C

Procedure

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).

Workup

customThe phases were separated
washthe organic layer was washed with water
dry with materialdried over sodium sulfate
concentrationconcentrated
customThe residue was purified by column chromatography on silica gel (eluent: methanol/ethyl acetate 5:5)

Sources & evidence

ORD record: ord-0d68131f35e145e38c5d1b3c4941ca39
Source dataset: uspto-grants-2015_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08980892B2

Reaction notes

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