Dimethylformamide → 4-Bromo-2,5-dimethylbenzaldehyde

HRID 719040Notes

Reaction equation

Br[C:2]1[CH:7]=[C:6]([CH3:8])[C:5]([Br:9])=[CH:4][C:3]=1[CH3:10].[Li]CCCC.CN([CH:19]=[O:20])C>C1COCC1.[Cl-].[NH4+]>[Br:9][C:5]1[C:6]([CH3:8])=[CH:7][C:2]([CH:19]=[O:20])=[C:3]([CH3:10])[CH:4]=1

Participants

Conditions

Temperature: -78 °C

Procedure

4 g (15 mmol, 1 eq.) of 1,4-dibromo-2,5-dimethylbenzene are solubilized in 50 mL of distilled THF, in a Schlenk tube under argon. The medium is then cooled to −78° C., then 6.6 mL (16.6 mmol, 1.1 eq.) of BuLi (2.5M in hexane) are added dropwise. After stirring at this temperature for 1 hour, 5.3 mL (68 mmol, 4.5 eq.) of freshly distilled DMF are added. The reaction medium is again stirred at this temperature for 1 hour, and then the temperature returns to ambient temperature overnight. Next, the medium is diluted with a solution of ammonium chloride and then extracted three times with ethyl acetate. The organic phases are combined, dried over magnesium sulphate, and concentrated under reduced pressure. The residue is purified by silica column chromatography (eluent: ethyl acetate/petroleum ether: 80/20), so as to give a white solid (m: 1.3 g, yield: 40%).

Workup

stirringThe reaction medium is again stirred at this temperature for 1 hour
customto ambient temperature
customovernight
extractionextracted three times with ethyl acetate
dry with materialdried over magnesium sulphate
concentrationconcentrated under reduced pressure
customThe residue is purified by silica column chromatography (eluent: ethyl acetate/petroleum ether: 80/20)
customso as to give a white solid (m: 1.3 g, yield: 40%)

Sources & evidence

ORD record: ord-64e31ead7aa2496cb1ada202bf8f9901
Source dataset: uspto-grants-2015_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09196847B2

Reaction notes

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