反应详情

47 g (0.2 mol) of 2-oxo-6-trifluoromethyl-1,2-dihydropyridine-3-carboxylic acid, 20 ml (0.25 mol) of propargyl bromide and 43 g (0.31 mol) of potassium carbonate are heated to a temperature of 75° C. in a mixture of 40 ml of dimethylformamide and 80 ml of acetonitrile in the presence of a catalytic amount of 18-crown-6 ether. After 5 hours, the mixture is partitioned between ethyl acetate and saturated sodium chloride solution. The crude product is filtered through a silica gel column using 15% ethyl acetate in hexane. The main component, which is obtained in the form of an oil, is the pure ethyl 2-prop-2-ynyloxy-6-trifluoromethylnicotinate; 1H-NMR (CDCl3): 8.31, d, CH, 7.38, d, CH, 5.13, d, CH2, 4.41, q, CH2, 2.48, t, CCH, 1.41 ppm, t, CH3. 36.3 g (0.13 mol) of this product is stirred over a period of 16 hours with a solution of 11.5 g (0.17 mol) of potassium hydroxide in 50 ml of water and 50 ml of dioxane. After acidification and extraction with ethyl acetate, crystalline 2-prop-2-ynyloxy-6-trifluoromethylnicotinic acid is obtained; 1H-NMR (CDCl3): 10.0, b, OH, 8.53, d, CH, 7.44, d, CH, 5.22, d, CH2, 2.54 ppm, t, CCH.

1. customthe mixture is partitioned between ethyl acetate and saturated sodium chloride solution
2. filtrationThe crude product is filtered through a silica gel column
3. customThe main component, which is obtained in the form of an oil
4. extractionAfter acidification and extraction with ethyl acetate