Br[C:2]1[CH:3]=[C:4]([CH:9]=[C:10]([CH2:12][CH3:13])[CH:11]=1)[C:5]([O:7][CH3:8])=[O:6].[Cu](C#N)[C:15]#[N:16]>CN(C=O)C>[C:15]([C:2]1[CH:3]=[C:4]([CH:9]=[C:10]([CH2:12][CH3:13])[CH:11]=1)[C:5]([O:7][CH3:8])=[O:6])#[N:16]The product methyl 3-bromo-5-ethylbenzoate (0.9 g, 3.7 mmol) was dissolved in dry DMF (50 mL) and copper cyanide (0.84 g, 9.43 mmol) was added. The reaction mixture was heated to 150° C. under argon atmosphere for 12 h (monitored by TLC; petroleum ether/EtOAc 9:1). The reaction mixture was allowed to come to room temperature and then quenched with saturated ammonium chloride solution. The reaction mixture was diluted with EtOAc and filtered through a Celite bed. The filtrate was diluted with EtOAc and the organic layer was washed with water and brine. The solvent was evaporated under reduced pressure. The crude product was purified by column chromatography (silica 60-120 mesh, eluent 5% EtOAc in petroleum ether) to get methyl 3-cyano-5-ethylbenzoate (0.27 g, yield 39%) as colorless liquid, which was carried through without further purification.
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