반응 #44929

반응 방정식

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

수율 37.3%

용매

hexane

CH2Cl2

CH2Cl2

반응 조건

후처리

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

실험 절차

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.

출처