Reaktion #2178362

Reaktionsgleichung

sodium cyanoborohydride

methyl 4-aminobenzoate

sodium hydrogen carbonate

2-ethyl-1-(5-methoxy-3-methyl-1-benzofuran-2-yl)butan-1-one

sodium hydrogen carbonate

→

compound

Ausbeute 59.1%

methyl 4-{[2-ethyl-1-(5-methoxy-3-methyl-1-benzofuran-2-yl)butyl]amino}benzoate

Ausbeute 59.1%

Lösungsmittel

tetrahydrofuran

acetic acid

methylene chloride

triethylamine

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeto quench
2. 2
   Sonstigethe reaction, methylene chloride
3. 3
   Sonstigewas evaporated in an evaporator
4. 4
   Extraktionthe residue was extracted with ethyl acetate
5. 5
   WaschenThe extract was washed with saturated brine
6. 6
   Trocknendried over magnesium sulfate
7. 7
   Einengenconcentrated under reduced pressure
8. 8
   Sonstigeto give a dark brown oil
9. 9
   workup.STIRRINGthe mixture was stirred at room temperature for 1.5 hr
10. 10
    Sonstigeto quench
11. 11
    Sonstigethe reaction
12. 12
    Extraktionthe reaction mixture was extracted with ethyl acetate
13. 13
    WaschenThe extract was washed with saturated brine
14. 14
    Trocknendried over magnesium sulfate
15. 15
    Einengenconcentrated under reduced pressure
16. 16
    SonstigeThe residue was purified by silica gel column chromatography (20% ethyl acetate/hexane)

Vorschrift

To a mixture of 2-ethyl-1-(5-methoxy-3-methyl-1-benzofuran-2-yl)butan-1-one (800 mg) synthesized above, methyl 4-aminobenzoate (464 mg), triethylamine (3.43 mL) and methylene chloride (10 mL) was added titanium (IV) chloride (404 μL), and the mixture was stirred overnight at room temperature under argon atmosphere. Saturated aqueous sodium hydrogen carbonate solution was added to quench the reaction, methylene chloride was evaporated in an evaporator, and the residue was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure to give a dark brown oil. To a solution (20 mL) of the obtained oil in tetrahydrofuran were added acetic acid (882 μL) and sodium cyanoborohydride (386 mg), and the mixture was stirred at room temperature for 1.5 hr. Saturated aqueous sodium hydrogen carbonate solution was added to quench the reaction, and the reaction mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (20% ethyl acetate/hexane) to give the title object compound (718 mg, 59%) as a brown oil.

Quelle