反应详情

温度

50 °C

To a solution of 3-ethyl-4-hydroxy-5-methyl-benzoic acid (80.3 g, 0.446 mol) is DMF (500 mL), KHCO3 (53.5 g, 0.535 mol) followed by benzylbromide (114.3 g, 0.668 mol) is added. The mixture is stirred at 50° C. for 18 h before it is cooled to rt, diluted with water (250 mL), and extracted with TBME (2×250 mL). The org. extracts are washed with water, and then concentrated. The crude product is purified by CC on silica gel eluting with heptane:EA 19:1 to 9:1 to give 3-ethyl-4-hydroxy-5-methyl-benzoic acid benzyl ester (108.5 g) as a beige solid; 1H NMR (CDCl3): δ1.28 (t, J=7.5 Hz, 3H), 2.30 (s, 3H), 2.68 (q, J=7.8 Hz, 2H), 5.24 (s, 1H), 5.37 (s, 2H), 7.33-7.45 (m, 3H), 7.45-7.50 (m, 2H), 7.77 (s, 1H), 7.79 (s, 1H).

1. additionis added
2. temperatureis cooled to rt
3. extractionextracted with TBME (2×250 mL)
4. washextracts are washed with water
5. concentrationconcentrated
6. customThe crude product is purified by CC on silica gel eluting with heptane:EA 19:1 to 9:1