反应详情

To a mixture of (4-nitrophenoxy)acetic acid 22 (80 g, 406 mmol) and (4-nitrophen-oxy)-acetic acid-2-hydroxyethyl ester 23 (80 g, 332 mmol) in anhydrous dichloro-methane (2 L) under nitrogen atmosphere was added a solution of 1,3-di-cyclohexyl carbodiimide (128 g, 620 mmol) in anhydrous dichloromethane (750 ml) drop wise. The reaction mixture was stirred at room temperature for 8 hours. The solids were filtered off and dichloromethane distilled off to get crude 24. The crude 24 was purified by column chromatography on silica gel using hexane:ethyl acetate (95:5) to get pure 24 (75 grams, 54%) as a white powder with an m.p. between 138-139° C.

1. filtrationThe solids were filtered off
2. distillationdichloromethane distilled off
3. customto get crude 24
4. customThe crude 24 was purified by column chromatography on silica gel