反応 #1150

反応方程式

methyl 2-formyl-5-methoxyphenoxyacetate

1,8-diazabicyclo[5.4.0]-7-undecene

→

methyl 6-methoxybenzofuran-2-carboxylate

収率 57.0%

溶媒

toluene

反応条件

後処理

1. 1
   温度was heated under refluxing conditions for 4 hours
2. 2
   濃縮The reaction mixture was concentrated under reduced pressure
3. 3
   workup.ADDITIONafter 6N hydrochloric acid was added
4. 4
   抽出the residue was extracted with ethyl acetate
5. 5
   洗浄After the ethyl acetate layer was washed with water
6. 6
   乾燥dried (MgSO4)
7. 7
   workup.DISTILLATIONthe solvent was distilled off
8. 8
   workup.ADDITION10% hydrochloric acid-methanol (30 ml) was added to the residue
9. 9
   温度by heating at 70° to 80° C. for 4 hours
10. 10
    濃縮The reaction mixture was concentrated under reduced pressure
11. 11
    workup.ADDITIONwater was added
12. 12
    抽出followed by extraction with ethyl acetate
13. 13
    洗浄After the ethyl acetate layer was washed with water
14. 14
    乾燥dried (MgSO4)
15. 15
    workup.DISTILLATIONthe solvent was distilled off
16. 16
    洗浄From the fraction eluted with chloroform-hexane (1:2

実験手順

A mixture of methyl 2-formyl-5-methoxyphenoxyacetate (27.7 g), 1,8-diazabicyclo[5.4.0]-7-undecene (40.8 g) and toluene (200 ml) was heated under refluxing conditions for 4 hours. The reaction mixture was concentrated under reduced pressure; after 6N hydrochloric acid was added, the residue was extracted with ethyl acetate. After the ethyl acetate layer was washed with water and dried (MgSO4), the solvent was distilled off; 10% hydrochloric acid-methanol (30 ml) was added to the residue, followed by heating at 70° to 80° C. for 4 hours. The reaction mixture was concentrated under reduced pressure; water was added, followed by extraction with ethyl acetate. After the ethyl acetate layer was washed with water and dried (MgSO4), the solvent was distilled off; the residue was subjected to silica gel column chromatography. From the fraction eluted with chloroform-hexane (1:2, v/v), methyl 6-methoxybenzofuran-2-carboxylate (14.3 g, 57%) was obtained, which was then recrystallized from dichloromethane-isopropyl ether to yield colorless prisms having a melting point of 97° to 98° C.

出典