Trifluoroacetic acid → ethyl (2E)-3-(7-methoxy-2-oxo-1-(2-oxoethyl)-1,2-dihydroquinolin-4-yl)acrylate

Participants

Reaction Steps

To 0.16 g of ethyl (2E)-3-(1-(1,3-dioxolan-2-ylmethyl)-7-methoxy-2-oxo-1,2-dihydroquinolin-4-yl)acrylate, 2 mL of 90% aqueous trifluoroacetic acid solution was added and stirred for 2 hours. The solvent was removed under reduced pressure, and aqueous saturated sodium hydrogen carbonate solution and chloroform were added. The organic layer was separated, and the aqueous layer was extracted with chloroform. The organic layer and extracts were combined, 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 (eluent; chloroform) to give 84 mg of ethyl (2E)-3-(7-methoxy-2-oxo-1-(2-oxoethyl)-1,2-dihydroquinolin-4-yl)acrylate as a yellow oil. (2) To 3 mL of a dichloromethane solution containing 84 mg of ethyl (2E)-3-(7-methoxy-2-oxo-1-(2-oxoethyl)-1,2-dihydroquinolin-4-yl)acrylate, 98 mg of tert-butyl (2,3-dihydro-1,4-benzodioxin-6-ylmethyl)(piperidin-4-yl)carbamate and 14 μL of acetic acid were added and stirred for 1 hour. To the reaction mixture, 81 mg of sodium triacetoxyborohydride was added and stirred for 2 hours. Water, ethyl acetate and aqueous saturated sodium hydrogen carbonate solution were added, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate. The organic layer and extracts were combined, 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 [eluent; chloroform:methanol=100:1] to give 0.11 g of ethyl (2E)-3-(1-(2-(4-((tert-butoxycarbonyl)(2,3-dihydro-1,4-benzodioxin-6-ylmethyl)amino)piperidin-1-yl)ethyl)-7-methoxy-2-oxo-1,2-dihydroquinolin-4-yl)acrylate as a yellow oil.

Provenance & Evidence