Reaktion #68172

Reaktionsgleichung

1-(1,3-dioxolan-2-ylmethyl)-5-benzyloxyquinolin-2(1H)-one

→

(5-benzyloxy-2-oxoquinolin-1(2H)-yl)acetaldehyde

Lösungsmittel

trifluoroacetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe solvent was removed under reduced pressure
2. 2
   Extraktionwas extracted with ethyl acetate
3. 3
   WaschenThe organic layer was washed sequentially with water and aqueous saturated sodium chloride solution
4. 4
   Trocknendried over anhydrous magnesium sulfate
5. 5
   Sonstigethe solvent was removed under reduced pressure

Vorschrift

750 mg of 1-(1,3-dioxolan-2-ylmethyl)-5-benzyloxyquinolin-2(1H)-one was dissolved in 3 mL of 90% aqueous trifluoroacetic acid solution, and stirred at room temperature for 3 days. The solvent was removed under reduced pressure, and after it was alkalized by aqueous saturated sodium hydrogen carbonate solution, it was extracted with ethyl acetate. The organic layer was washed sequentially with water and aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure to give (5-benzyloxy-2-oxoquinolin-1(2H)-yl)acetaldehyde as a pale yellow solid. (2) To 25 mL of a chloroform solution containing (5-benzyloxy-2-oxoquinolin-1(2H)-yl)acetaldehyde and 877 mg of tert-butyl (2,3-dihydro-1,4-benzodioxin-6-ylmethyl)(piperidin-4-yl)carbamate, 144 μL of acetic acid was added, and stirred at room temperature for 1 hour. To the reaction mixture, 811 mg of sodium triacetoxyborohydride was added, and stirred for 1.5 hours. Aqueous saturated sodium hydrogen carbonate solution was added, the organic layer was separated. The organic layer was washed with aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The residue thus obtained was purified by silica gel column chromatography [Silica Gel; Kanto Chemical Co., Inc., Silica Gel 60, eluent; chloroform:methanol=100:1], to give 592 mg of tert-butyl (2,3-dihydro-1,4-benzodioxin-6-ylmethyl) (1-(2-(5-benzyloxy-2-oxoquinolin-1(2H)-yl)ethyl)piperidin-4-yl)carbamate as a pale brown foam.

Quelle