[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.C(OCC)(=O)C.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-bromo-pyridin-4-yl)-acetonitrile (1.20 g, 6.09 mmol) and the 1,2-dibromoethane (0.663 mL, 7.61 mmol) in a mixture of dry Et2O (5 mL) and dry DMSO (1 mL) is added to a suspension of NaH (60% dispersion in mineral oil, 585 mg, 14.6 mmol) in dry 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 ethyl acetate (10 mL) are added, phases are separated and the aqueous layer is extracted with ethyl acetate (3×10 mL). The combined organic layers are washed with brine (30 mL) and dried over MgSO4, filtered and concentrated. The residue is purified on SiO2 eluting with a gradient of 0-60% ethyl acetate in heptane to afford 1-(2-bromo-pyridin-4-yl)-cyclopropanecarbonitrile as a solid (ES+ m/z 223.36; 225.39).
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