反应 #1343

反应方程式

triethyl orthoacetate

5,5-dichloro-4-hydroxy-2-methyl-6,6,6-trifluorohex-2-ene

isobutyric acid

→

ethyl 6,6-dichloro-3,3-dimethyl-7,7,7-trifluorohept-4-enoate

反应条件

后处理

1. 1
   温度was heated at the reflux temperature
2. 2
   其他condensed
3. 3
   其他collected in a Dean & Stark apparatus
4. 4
   workup.ADDITIONcontaining molecular sieves (4A)
5. 5
   其他to collect the by-product ethanol
6. 6
   其他separate it from the orthoacetate which
7. 7
   其他After 30 minutes the more volatile components were removed by evaporation under reduced pressure
8. 8
   其他collected
9. 9
   温度This was then heated with isobutyric acid (10 μl) at the reflux temperature for 16 hours under a condenser
10. 10
    workup.ADDITIONcontaining molecular sieves (4A)
11. 11
    其他to remove ethanol from the condensate
12. 12
    其他The residual oil was subjected to purification by column chromatography
13. 13
    workup.ADDITIONa 15:1 (by volume) mixture of hexane

实验过程

A mixture of triethyl orthoacetate (25 ml), 5,5-dichloro-4-hydroxy-2-methyl-6,6,6-trifluorohex-2-ene (3.5 g), and isobutyric acid (0.11 g) was heated at the reflux temperature. The refluxing volatiles were condensed and collected in a Dean & Stark apparatus containing molecular sieves (4A) to collect the by-product ethanol and separate it from the orthoacetate which was returned to the mixture. After 30 minutes the more volatile components were removed by evaporation under reduced pressure and the residual oil (consisting principally of 5,5-dichloro-4-(1,1-diethoxyethoxy)-2-methyl-6,6,6-trifluorohex-2-ene, 3.8 g) collected. This was then heated with isobutyric acid (10 μl) at the reflux temperature for 16 hours under a condenser containing molecular sieves (4A) to remove ethanol from the condensate. The residual oil was subjected to purification by column chromatography using a 15:1 (by volume) mixture of hexane:ethyl acetate as eluant and a silica gel column (230-400 mesh, 60 Å) to obtain ethyl 6,6-dichloro-3,3-dimethyl-7,7,7-trifluorohept-4-enoate, identified by nuclear magnetic resonance, and gas chromatographic mass-spectroscopy.

来源