反应详情

To a mixture of (4-nitrophenoxy)acetic acid 40 (80 g, 406 mmol) and (4-nitro-phenoxy)acetic acid-2-hydroxyethyl ester 41 (80 g, 332 mmol) in anhydrous dichloromethane (2 L) under nitrogen atm. was added a solution of 1,3-dicyclohexyl 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 42. The crude 42 was purified by column chromatography on silica gel using hexane:ethyl acetate (95:5) to get pure 42 (75 g, 54%) as a white powder. M.p: 138-139° C.

1. filtrationThe solids were filtered off
2. distillationdichloromethane distilled off
3. customto get crude 42
4. customThe crude 42 was purified by column chromatography on silica gel