반응 #1343

반응 방정식

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

반응 조건

후처리

1. 1
   온도was heated at the reflux temperature
2. 2
   기타condensed
3. 3
   기타collected in a Dean & Stark apparatus
4. 4
   workup.ADDITIONcontaining molecular sieves (4A)
5. 5
   기타to collect the by-product ethanol
6. 6
   기타separate it from the orthoacetate which
7. 7
   기타After 30 minutes the more volatile components were removed by evaporation under reduced pressure
8. 8
   기타collected
9. 9
   온도This 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
    기타to remove ethanol from the condensate
12. 12
    기타The residual oil was subjected to purification by column chromatography
13. 13
    workup.ADDITIONa 15:1 (by volume) mixture of hexane

실험 절차

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.

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