[Br:1][C:2]1[CH:7]=[C:6]([Br:8])[CH:5]=[C:4]([CH2:9]Br)[C:3]=1[O:11][CH3:12].[C-:13]#[N:14].[Na+]>C(O)C.O>[Br:1][C:2]1[CH:7]=[C:6]([Br:8])[CH:5]=[C:4]([CH2:9][C:13]#[N:14])[C:3]=1[O:11][CH3:12]A solution of the product of stage (c) (183 g) in ethanol (150 ml) was heated to reflux. A solution of sodium cyanide (25 g) in hot water (50 ml) was added which maintained gentle refluxing. The mixture was then stirred for 5 minutes, poured into ice water, and the product was filtered off, taken up in dichloromethane, washed with water, dried over magnesium sulphate and filtered. The solvent was removed to give a brown oil which slowly crystallised. Recrystallisation from petroleum ether gave the title product as colourless needles, mp 87°-88° C.
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