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

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Reaction Steps

Add magnesium chloride (27.7 g, 0.29 mol) to 2-methoxyethanol (400 mL) and heat the mixture to reflux. Add a solution of 3-(3,4-Dihydro-2H-quinolin-1-yl)-2-oxopropionic acid ethyl ester (0.29 mol) in 2-methoxyethanol (100 mL) and tetrahydrofuran (40 mL) slowly to the MgCl2 mixture over 1 hour. Upon completion of addition, stir the mixture for 5 hours at reflux, and then concentrate under reduced pressure. Treat the concentrated crude mixture with 2N hydrochloric acid (500 mL) and extract with dichloromethane (3×400 mL). Combine the organic layers, dry over sodium sulfate, filter, and concentrate under reduced pressure. Subject the residue to silica gel chromatography, eluting with 20% ethyl acetate/hexanes. Combine fractions containing product and concentrate them under reduced pressure to provide the desired compound as an orange solid (31.6 g, 48%).

Provenance & Evidence