[Br:1][C:2]1[CH:7]=[C:6]([CH2:8][C:9]#[N:10])[CH:5]=[CH:4][N:3]=1.Br[CH2:12][CH2:13]Br.CCOCC.[H-].[Na+]>CS(C)=O.CCOC(C)=O.O>[Br:1][C:2]1[CH:7]=[C:6]([C:8]2([C:9]#[N:10])[CH2:13][CH2:12]2)[CH:5]=[CH:4][N:3]=1A solution of (2-bromopyridin-4-yl)-acetonitrile (1.20 g, 6.09 mmol) and the 1,2-dibromoethane (0.663 mL, 7.61 mmol) in a mixture of anhydrous Et2O (5 mL) and anhydrous DMSO (1 mL) is added to a suspension of NaH (60% dispersion in mineral oil, 585 mg, 14.6 mmol) in anhydrous DMSO (10 mL) while controlling the resulting exotherm by cooling in a water bath, and the resulting mixture is stirred at room temperature. After 18 hours, water (10 mL) and EtOAc (10 mL) are added, phases are separated and the aqueous layer is extracted with EtOAc (3×10 mL). The combined organic layers are washed with brine (30 mL) and dried over MgSO4, filtered and concentrated. The residue is purified by silica gel chromatography eluting with a gradient of 0-60% EtOAc in heptane to afford 1-(2-bromopyridin-4-yl)-cyclopropanecarbonitrile as a solid. MS m/z 223.4, 225.4.
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