33143-92-9

33143-29-2

General procedure for the synthesis of 2,2-dimethyl-6-cyano-2H coumarin from 4-((2-methylbut-3-yn-2-yl)oxy)benzonitrile: 4-((2-methylbut-3-yn-2-yl)oxy)benzonitrile (1.0 g, 5.40 mmol) was dissolved in ethylene glycol (5 mL/g of substrate), and the reaction mixture was heated to 210-215 °C,. maintained for 24 hours. After completion of the reaction, the mixture was cooled to room temperature and diluted with water. The mixture was extracted with ether (2 x 25 mL), the organic layers were combined, dried over anhydrous magnesium sulfate and filtered. The solvent was removed by concentration under reduced pressure to give a bright yellow solid. Recrystallization by petroleum ether gave 2,2-dimethyl-6-cyano-2H coumarin as a yellow powder (1.0 g, quantitative yield) with a melting point of 47-48 °C (literature value: 47 °C). IR spectrum (thin film method, cm^-1): 3054, 2985, 2226, 1605, 1487, 1421, 1369, 1265, 1212, 1148, 1128, 1107, 961, 896, 828, 739, 705. ^1H NMR (400MHz, CDCl3): δ 1.45 (s, 6H). 5.70 (d, 1H, J=11.6Hz), 6.28 (d, 1H, J=11.6Hz), 6.78 (d, 1H, J=8.4Hz), 7.24 (d, 1H, J=4.0Hz), 7.37 (dd, 1H, J=8.4Hz, 4.0Hz). ^13C NMR (100 MHz, CDCl3): δ 28.4, 77.9, 103.8, 117.2, 119.3, 120.6, 121.7, 130.1, 132.2, 133.3, 156.8.