Reaction Steps
To a stirred solution of iodide 4 (7.4 g, 0.015 mol, 1.0 equiv) in N,N-dimethyl formamide (25 ml) under N2 was added copper cyanide. The resultant suspension was refluxed for 1 hour. The reaction was monitored by TLC and checked for the completion. Heating was discontinued and the reaction mixture was cooled down to 80° C. Ice water (15 ml), 25% aqueous ammonia (15 ml), and ethyl acetate (50 ml) were added to quench the reaction. The mixture was filtered to remove the solids. From the filtrate organic layer was separated. The organic layer was washed with water, saturated brine and dried over anhydrous sodium sulfate. Solvent was removed under reduced pressure and the crude material dried at 60° C. under high vacuum then purified by column with ethyl acetate as eluent to provide the product (3 g, 51%) as an off white solid. HPLC (Waters X-Terra 5 micron C18 column 4.6 mm×250 mm, 1.0 mL/min, mobile phase: 0.1% TEA in H2O/acetonitrile 70/30, 30 min elution) tR 23.70 min, 99.4% purity; 1H NMR (400 MHz, CDCl3) δ8.10 (t, J=2.9 Hz, 1H), 8.06 (t, J=2.7 Hz, 1H), 8.04 (m, 1H), 7.85 (t, J=2.5 Hz, 1H), 7.83 (m, 1H), 7.81 (d, J=1.8 Hz, 1H), 7.95 (d, J=1.6 Hz, 1H), 7.37 (s, 1H), 7.65 (t, J=7.8 Hz, 1H), 7.45 (d, J=8.0 Hz, 1H), 6.41 (s, 1H), 5.94 (s, 2H), 2.88 (m, 1H), 2.24 (s, 3H), 0.86 (dd, J=6.9, 6.1 Hz, 2H) 0.61 (m, 2H) ppm; 13C NMR (400 MHz, CDCl3) δ186.6, 167.2, 151.5, 141.3, 140.7, 140.3, 135.1, 134.5, 134.0, 132.2, 131.8, 129.5, 128.7, 126.2, 118.1, 113.0, 103.7, 30.9, 23.2, 17.7, 6.8 ppm.
