Nitric Acid → 1-(2,3-Difluoro-5-nitrophenyl)ethanone

HRID 1941783Notes

Reaction equation

[F:1][C:2]1[C:7]([F:8])=[CH:6][CH:5]=[CH:4][C:3]=1[C:9](=[O:11])[CH3:10].[N].[N+:13]([O-])([OH:15])=[O:14].C(OCC)(=O)C>S(=O)(=O)(O)O>[F:1][C:2]1[C:7]([F:8])=[CH:6][C:5]([N+:13]([O-:15])=[O:14])=[CH:4][C:3]=1[C:9](=[O:11])[CH3:10]

Participants

Conditions

Temperature: 0 °C

Procedure

Under an inert atmosphere of nitrogen 1-(2,3-difluoro-phenyl)-ethanone (5.0 g (32 mmol) was added dropwise to sulphuric acid (95-97%, 20 ml), cooled to 0° C., at such a rate that the temperature was maintained below 5° C. Thereafter, the reaction mixture was cooled to −15° C. and a solution of nitric acid (3.22 ml, 46.4 mmol) in sulphuric acid (95-97%, 4.6 ml) was added dropwise at −15° C. After stirring at −10° C. for 45 minutes, the mixture was poured on ice. Ethyl acetate was added, then the organic layer separated, washed with water, dried over sodium sulphate, and evaporated at reduced pressure. Purification of the crude light yellow oil (5.64 g) by chromatography on silica gel using a gradient of heptane/ethyl acetate=100:0 to 0:100 yielded the 1-(2,3-difluoro-5-nitro-phenyl)-ethanone (1.83 g, 28% of theory) as a light yellow oil together with a mixture of 1-(2,3-difluoro-5-nitro-phenyl)-ethanone and 1-(2,3-difluoro-6-nitro-phenyl)-ethanone.

Workup

temperatureat such a rate that the temperature was maintained below 5° C
temperatureThereafter, the reaction mixture was cooled to −15° C.
additionthe mixture was poured on ice
customthe organic layer separated
washwashed with water
dry with materialdried over sodium sulphate
customevaporated at reduced pressure
customPurification of the crude light yellow oil (5.64 g) by chromatography on silica gel using a gradient of heptane/ethyl acetate=100:0 to 0:100

Sources & evidence

ORD record: ord-82a723b392734ef39415a928ac534b32
Source dataset: uspto-grants-2013_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08389513B2

Reaction notes

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