Dimethylformamide → Ethyl 8-chloro-1-cyclopropyl-7-fluoro-9-methyl-4-oxo-4H-quinolizine-3-carboxylate

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Reaction Steps

Under nitrogen, ethyl 8-hydroxy-1-cyclopropyl-7-fluoro-9-methyl-4-oxo-4H-quinolizine-3-carboxylate (7A, 1.52 g, 5 mmol) was dissolved in methylene chloride (10 mL), and treated with DMF (0.73 g, 10 mmol) and POCl3 (1.53 g, 10 mmol). After stirring overnight, the mixture was poured into 10 mL of ice water. The organic layer was separated, and the aqueous layer was extracted with methylene chloride (10 mL×2). The organic layers were combined, washed with saturated NaHCO3 and brine, dried (MgSO4), filtered and concentrated to give the crude product which was chromatographed (silica gel, 50% ethyl acetate/hexane) to give the title compound (IIA, 1.3 g, 80%). 1H NMR (300 MHz, CDCl3): δ0.75 (m, 2H), 1.08 (m, 2H), 1.42 (t, 3H), 2.30 (m, 1H), 3.19 (s, 3H), 4.42 (q, 4H), 8.39 (s, 1H), 9.43 (d, 1H): MS (DCI/NH3) m/e 324 (M+H)+. Anal. Calcd for C16H15ClFNO3 : C, 59.35; H, 4.67; N, 4.32. Found C, 59.68; H, 4.76; N, 4.22.

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