1,1'-Biphenyl, mixt. with 1,1'-oxybis(benzene) → Ethyl 8-fluoro-6,7-dimethoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate

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Reaction Steps

To Dowtherm (25 mL) heated at 250° C. was added diethyl 2-(((2-fluoro-3,4-dimethoxyphenyl)amino)methylene)malonate (10 g, 29.3 mmol). The mixture was stirred at the same temperature for 40 mins. LCMS indicated completion of the reaction. The reaction was allowed to cool at rt for 5 mins and was then poured into cold hexane, the yellow precipitate was collected by filtration, washed with hexane and dried in the air. This reaction was carried out in similar scale for several times. From a total of 72 g of diethyl 2-(((2-fluoro-3,4-dimethoxyphenyl)amino)methylene)malonate (211 mmol), ethyl 8-fluoro-6,7-dimethoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate (38 g, 129 mmol, 61.0% yield) was obtained as a yellow solid. LCMS (M+H)+: 296.0

Provenance & Evidence