Ethanol → 3-Amino-2-[1,1'-biphenyl]-4-yl-6-bromo-4-quinolinecarboxylic acid

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Reaction Conditions

Reaction Steps

A 5.0 g portion of 5-bromoisatin was suspended in 25 ml of water in a three-necked 1 liter flask equipped with a reflux oondenser and addition funnel. A solution of 4.36 g of sodium hydroxide in 20 ml of water was added and the mixture heated to 90° C. A solution of 9.9 g of 2-amino-4'-phenylacetophenone hydrochloride in 200 ml of a 50:50 mixture of ethanol:water was warmed slightly, then 100 ml of tetrahydrofuran was added to effect solution. This solution was added dropwise to the hot 5-bromoisatin solution over 1.5 hours with vigorous stirring. When addition was complete, the mixture was stirred at 90° C. for 1 hour, then the organic solvents were removed by distillation at 85° C. The solution was cooled and the red solids collected, washed with water and saved. The red solid saved above was suspended in 1 liter of water, stirred for 1 hour and then filtered. The filtrate was acidified to pH 5 with glacial acetic acid and the resulting yellow solids collected and washed with water. The second crop was pure giving 3.80 g of the desired product, mp 239°-240° C. (dec.).

Provenance & Evidence