1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → (E)-1'-Methyl-6-(3-oxo-3-(3-(thiophen-2-ylmethoxy)azetidin-1-yl)prop-1-enyl)-1H-spiro[[1,8]naphthyridine-3,4'-piperidin]-2(4H)-one

Participants

Reaction Steps

3-(Thiophen-2-ylmethoxy)-azetidine hydrochloride (45.8 mg, 0.22 mmol), EDCI (40.26 mg, 0.21 mmol), HOBt (28.5 mg, 0.21 mmol) and diisopropylethylamine (62 μL, 0.35 mmol) were successively added to a solution of (E)-3-(7-oxo-5,6,7,8-tetrahydro-1,8-naphthyridin-3-yl)-acrylic acid hydrochloride (47.0 mg, 0.14 mmol) in dimethylformamide (5 mL) at room temperature. The reaction mixture was stirred overnight and then diluted by addition of ethyl acetate (20 ml) and water (20 mL). The aqueous layer was separated and extracted with ethyl acetate (2×20 mL). The combined organic phases were washed with a saturated solution of sodium chloride (3×20 mL), dried over sodium sulfate, filtered and concentrated to dryness. The residue was purified by chromatography on silica gel using dichloromethane/methanol (95:5 to 0:1) as eluent. After precipitation in a mixture dichloromethane/diethylether/pentane, the title product was obtained as a white solid (12 mg, 24%).

Provenance & Evidence