反応 #51859

反応方程式

triethylamine

benzyl alcohol

3,4-dimethoxyphenylacetic acid

thionyl chloride

→

title compound

収率 60.1%

(3,4-Dimethoxy-phenyl)-acetic acid benzyl ester

収率 60.1%

溶媒

Water

dichloromethane

dichloromethane

1,2-dichloroethane

反応条件

後処理

1. 1
   温度The resulting solution was heated
2. 2
   温度to reflux for 16 hours
3. 3
   その他the volatile fractions removed in vacuo
4. 4
   その他Residual thionyl chloride was removed by an azeotrope with toluene (3×200 cm3)
5. 5
   その他to afford a crude brown oil
6. 6
   温度cooled to 0° C. in an ice bath
7. 7
   温度warmed to ambient temperature
8. 8
   抽出the aqueous extracted with dichloromethane (2×100 cm3)
9. 9
   乾燥The combined dichloromethane extracts were dried over sodium sulfate, vacuum
10. 10
    ろ過filtered
11. 11
    その他the filtrate volatile fractions removed in vacuo
12. 12
    その他to afford a crude brown oil
13. 13
    その他The crude product was purified by column chromatography (silica, eluting with hexane-ethyl acetate 1:0 to 1:1)

実験手順

To a stirred mixture of commercially available 3,4-dimethoxyphenylacetic acid (100.0 g, 510 mmol) in anhydrous 1,2-dichloroethane (500 cm3) at ambient temperature under an atmosphere of dry nitrogen was added thionyl chloride (112 cm3, 1.53 mol) portionwise over 20 minutes. The resulting solution was heated to reflux for 16 hours. The brown solution was cooled to ambient temperature and the volatile fractions removed in vacuo. Residual thionyl chloride was removed by an azeotrope with toluene (3×200 cm3) to afford a crude brown oil. The crude oil was dissolved in anhydrous dichloromethane (400 cm3) and cooled to 0° C. in an ice bath. To the cooled solution was added triethylamine (75 cm3, 535 mmol) dropwise over 10 minutes followed by a solution of benzyl alcohol (50 cm3, 485 mmol) dissolved in anhydrous dichloromethane (200 cm3). The mixture was stirred for 20 hours and warmed to ambient temperature. Water was added to the mixture (700 cm3) and the aqueous extracted with dichloromethane (2×100 cm3). The combined dichloromethane extracts were dried over sodium sulfate, vacuum filtered and the filtrate volatile fractions removed in vacuo to afford a crude brown oil. The crude product was purified by column chromatography (silica, eluting with hexane-ethyl acetate 1:0 to 1:1) to afford the title compound as a pale yellow viscous oil (83.4 g, 57.2%) with a positive ion ESI (M−1H)+287.3.

出典