反应详情

To a mixture of (4-aminophenoxy)-acetic acid methyl ester 3 (20 g, 110.5 mmol) and benzyloxy acetic acid (20.4 g, 123 mmol) in anhydrous dichloromethane (200 ml) under nitrogen atmosphere was added dropwise a solution of 1,3-dicyclohexyl carbo-diimide (63.2 g, 306 mmol) in anhydrous dichloromethane (80 ml) then stirred at room temp. for 12 hours. The solids were filtered off, the dichloromethane was washed with 5% sodium bicarbonate solution (100 ml), water (100 ml) added, and the solids dried over sodium sulphate and distilled to get crude 49. Crude 49 was purified by column chromatography on silica gel using benzene as eluant to get pure 49 (25 g, 68.9%) as a white powder with an m.p. between 76-77.5° C. 1H NMR (CDCl3) δ 3.82 (s, 3H, ester), 4.10 (s, 2H, CH2), 4.62 (s, 2H, CH2), 4.66 (s, 2H, CH2), 6.88 (d, 2H, Ar), 7.38 (m, 5H, Ar), 7.46 (d, 2H, Ar), 8.24 (bs, 1H, NH)

1. filtrationThe solids were filtered off
2. washthe dichloromethane was washed with 5% sodium bicarbonate solution (100 ml), water (100 ml)
3. additionadded
4. dry with materialthe solids dried over sodium sulphate
5. distillationdistilled
6. customto get crude 49
7. customCrude 49 was purified by column chromatography on silica gel