Реакция #44929

Уравнение реакции

EtOAc

dimethylaminoethanol

6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid

dicyclohexylcarbodiimide

→

6-Hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid 2-dimethylaminoethyl ester

Выход 37.3%

Растворители

hexane

CH2Cl2

CH2Cl2

Условия реакции

Обработка

1. 1
   workup.ADDITIONwas added to the mixture
2. 2
   Другоеto form a cloudy suspension
3. 3
   workup.STIRRINGThe solution was stirred at room temperature overnight
4. 4
   Фильтрацияthe resulting white suspension was filtered
5. 5
   Другоеto give a clear solution
6. 6
   ПромывкаThe solution was washed three times with water
7. 7
   Другоеthe organic layer was collected
8. 8
   Сушкаdried over anhydrous sodium sulfate
9. 9
   ДругоеThe drying agent was removed by filtration
10. 10
    Концентрированиеthe filtrate was concentrated by rotary evaporation
11. 11
    Другоеyielding a viscous, yellowish oil
12. 12
    ДругоеThe residue obtained
13. 13
    ПромывкаThe column was eluted with EtOAc/hexane (1:1
14. 14
    Другоеv/v) to remove the less polar impurity
15. 15
    Промывкаto elute the desired product from the column

Методика

To a stirred solution of 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid (2.6 g, 10 mmol) in 80 mL of CH2Cl2 was added dicyclohexylcarbodiimide (2.2 g, 10 mmol). After stirring for 5 min, dimethylaminoethanol (0.93 g, 10 mmol) dissolved in 10 mL of CH2Cl2 was added to the mixture to form a cloudy suspension. The solution was stirred at room temperature overnight, and the resulting white suspension was filtered to give a clear solution. The solution was washed three times with water, and the organic layer was collected and dried over anhydrous sodium sulfate. The drying agent was removed by filtration and the filtrate was concentrated by rotary evaporation, yielding a viscous, yellowish oil. The residue obtained was loaded to a silica gel column with a mixed solvent of EtOAc and hexane (1:1, v/v). The column was eluted with EtOAc/hexane (1:1, v/v) to remove the less polar impurity. Subsequently, a mixed solvent of CH2Cl2/MeOH/NH4OH (90:10:0.5, v/v/v) was used to elute the desired product from the column. 1.2 g of 6-Hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid 2-dimethylaminoethyl ester were obtained as a viscous yellowish oil, which solidified upon standing at room temperature. MS: m/z=322.2 (M+H+). 1H NMR (CDCl3, 300 Hz) 4.19 (t, J=5.8 Hz, 2H), 2.52-1.80 (m, 4H), 2.48 (t, 2H), 2.20 (s, 6H), 2.18 (s, 3H), 2.16 (s, 3H), 2.06 (s, 3H), 1.61 (s, 3H). 13C NMR (CDCl3, 75 Hz) 173.9, 145.6, 145.4, 122.5, 121.6, 118.8, 116.9, 77.0, 63.3, 57.5, 45.7, 30.6, 25.4, 21.0, 12.3, 11.9, 11.3.

Источник