反应详情

To an ice-cooled solution of 3-(4-carbamoyl-2,6-dimethyl-phenyl)-propionic acid tert-butyl ester (7.00 g, 25.2 mmol) and triethylamine (7.66 g, 75.7 mmol) in DCM (100 mL), trifluoroacetic anhydride (6.06 g, 28.8 mmol) is added slowly so that the reaction temperature stays below 15° C. The clear yellow solution is stirred at rt for 1 h before it is washed twice with water (100 mL) and concentrated. The crude product is purified by recrystallisation from methanol to give 3-(4-cyano-2,6-dimethyl-phenyl)-propionic acid tert-butyl ester (4.2 g) as a white solid, 1H NMR (CDCl3): δ 1.48 (s, 9H), 2.33-2.37 (m, 2H), 2.38 (s, 6H), 2.94-3.01 (m, 2H), 7.31 (s, 2H).

1. additionis added slowly so that the reaction temperature
2. customstays below 15° C
3. washis washed twice with water (100 mL)
4. concentrationconcentrated
5. customThe crude product is purified by recrystallisation from methanol