Sodium triacetoxyborohydride → 1-(2-{4-[(2,3-Dihydro[1,4]dioxino[2,3-c]pyridin-7-ylmethyl)amino]-2-methylpiperidin-1-yl}ethyl)-5,7-difluoroquinolin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

A solution of 1-[2-(4-amino-2-methylpiperidin-1-yl)ethyl]-5,7-difluoroquinolin-2(1H)-one (Intermediate 213, crude, 220 mg, 0.69 mmol) and 2,3-dihydro[1,4]dioxino[2,3-c]pyridine-7-carbaldehyde (WO 2004/058144) (114 mg, 0.69 mmol) in dry dichloroethane/methanol (4 mL, 4:1) was heated over 3 Å molecular sieves at 80° C. for 3 hours. The reaction mixture was cooled to 0° C., and sodium triacetoxy borohydride (299 mg, 1.38 mmol) was added. The resulting reaction mixture was stirred at room temperature for 16 hours and then was filtered through a 0.45 μm membrane and concentrated to dryness under reduced pressure. The residue was taken up in dichloromethane (20 mL) and saturated aqueous sodium hydrogen carbonate solution (5 mL). The pH of the aqueous phase was adjusted to pH˜10 with 1M aqueous sodium hydroxide solution. The aqueous phase was back extracted twice with dichloromethane (4×20 mL) and the combined organic phases were dried over sodium sulfate and concentrated under reduced pressure. Chromatography on silica gel with dichloromethane/methanol (17:3) gave 195 mg (69%) of the title compound as a white foam.

Provenance & Evidence