Methyl quinoline-6-carboxylate → Methyl 2-tert-butylquinoline-6-carboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a THF (20 ml) solution of methyl quinoline-6-carboxylate (984 mg, 5.26 mmol, J. O. C., 2002, 67, 7890) was added t-butylmagnesium chloride in THF (15.8 ml, 1M solution) dropwise at −78° C. over 30 min. The mixture was stirred at −78° C. for 30 minutes and at −40° C. for 30 minutes, then at room temperature for 1 hour. The reaction was quenched with saturated ammonium chloride aqueous solution (100 ml) and extracted with ethyl acetate (100 ml×2) which was dried over sodium sulfate. Then, filtration and evaporation gave a yellow oil, which was dissolved in THF (50 ml) and manganese dioxide (1.83 g 15.8 mmol) was added. After the mixture was stirred at room temperature for 2.5 hours, the precipitate was removed through a pad of celite and washed with ethyl acetate. The filtrate was concentrated and purified through silica gel column chromatography, eluting with Hexane/Ethyl acetate (20:1), to furnish the title compound (348 mg, 27% yield) as a white solid. 1H NMR (300 MHz, CDCl3) δ 1.48 (9H, s), 3.99 (3H, s), 7.59 (1H, d, J=8.8 Hz), 8.08 (1H, d, J=8.8 Hz), 8.17 (1H, d, J=8.8 Hz), 8.26 (1H, dd, J=2.2, 8.8 Hz), 8.55 (1H, d, J=2.2 Hz). MS (ESI): m/z 244 (M+H)+.

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