Sodium cyanoborohydride → 6-[({1-[2-(7-Methoxy-2-oxoquinolin-1(2H)-yl)ethyl]piperidin-4-yl}amino)methyl]-2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one

Participants

Reaction Conditions

Reaction Steps

1-[2-(4-Aminopiperidin-1-yl)ethyl]-7-methoxyquinolin-2(1H)-one (Intermediate 1, crude, 60 mg, 0.20 mmol), 3-oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazine-6-carbaldehyde (WO 2004/058144) (43 mg, 0.24 mmol) in dry dichloroethane/methanol (10 mL, 1:1) were heated over 3 Å molecular sieves at reflux for 4 hours. The reaction mixture was cooled to 0° C., and sodium cyanoborohydride (19 mg, 0.30 mmol) was added and it was stirred at room temperature for 2 hours. The mixture was filtered through a fritted funnel and concentrated to dryness under reduced pressure. The residue was taken up in ethyl acetate and washed with saturated sodium bicarbonate followed by saturated sodium chloride. The saturated sodium bicarbonate was extracted with chloroform, and the chloroform was washed with saturated sodium chloride. The ethyl acetate and chloroform extracts were combined, dried over sodium sulfate and concentrated to dryness under reduced pressure. Silica gel chromatography with dichloromethane/methanol/ammonia ammonia (8:2:0.01) gave title compound as a colorless oil, 27 mg (30%).

Provenance & Evidence