Magnesium Chloride → Ethyl 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline-1-carboxylate

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Reaktionsschritte

Anhydrous magnesium chloride (29.4 g, 0.31 mol) was suspended in 2-methoxyethanol (400 ml), and the mixture was stirred for 15 minutes at 125° C. A solution of 3-(3,4-dihydro-2H-quinolin-1-yl)-2-oxopropionic acid ethyl ester (76.57 g 0.31 mol) in 2-methoxyethanol (100 ml) was then added and the mixture stirred at 125° C. for 60 minutes. The mixture was stirred for a further 5 hours at reflux, cooled and evaporated to dryness. The residue was then acidified with 2 M hydrochloric acid (500 ml) and extracted with dichloromethane (3×500 ml). The combined organic layers were then washed with 5% sodium bicarbonate solution and dried over anhydrous magnesium sulfate before being evaporated to dryness. The residue was then purified on a silica gel chromatography column, eluting with ethyl acetate/hexanes (1:4) to provide 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline-1-carboxylic acid ethyl ester (31.0 g, 47%). 1H NMR (CDCl3) 400 MHz δ: 7.9 (d, 1H, J=8 Hz), 7.79 (s, 1H), 7.17 (m, 1H), 6.99 (d, 1H, J=7.2 Hz), 4.37 (m, 2H), 4.18 (t, 2H, J=5.6 Hz), 3.0 (t, 2H, J=6 Hz), 2.24 (t, 2H, J=6 Hz), 1.42 (t, 3H, J=7.2 Hz).

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