To 2 mL of a chloroform solution containing 60 mg of tert-butyl (2,3-dihydro-1,4-benzodioxin-6-ylmethyl)(1-(2-(5-amino-2-oxoquinolin-1(2H)-yl)ethyl)piperidin-4-yl)carbamate, 14 mg of triethylamine and 11 mg of acetyl chloride were added, and stirred at room temperature for 2 hours. Aqueous saturated sodium hydrogen carbonate solution was 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 to give 60 mg of tert-butyl (2,3-dihydro-1,4-benzodioxin-6-ylmethyl)(1-(2-(5-acetamino-2-oxoquinolin-1(2H)-yl)ethyl)piperidin-4-yl)carbamate as a yellow foam.
