Triethylamine → 3-amino-4-(2-chlorophenyl)-1,6,7-trimethyl-2(1H)-quinolone

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Reaction Steps

Triethylamine (0.7 ml) was added dropwise to a mixture of 4-(2-chlorophenyl)-1,2-dihydro-1,6,7-trimethyl-2-oxo-3-quinolinecarboxylic acid (1.71 g), diphenylphosphoryl azide (1.65 g) and benzene (25 ml) under stirring. The mixture was further stirred for 15 minutes at room temperature and for 30 minutes under reflux, and then distilled to remove the solvent. The residue was dissolved in a mixture of dioxane (20 ml) and 1sodium hydroxide (7.5 ml) , followed by refluxing for 15 minutes. The resulting solution was acidified with 2N hydrochloric acid and then stirred for 20 minutes at room temperature. The mixture was made alkaline with 2N sodium hydroxide. The resultant crystals were collected by filtration to give 3-amino-4-(2-chlorophenyl)-1,6,7-trimethyl-2(1H)-quinolone (1.08 g, 69.2%), which was recrystallized from a mixture of chloroform and ethanol to give colorless needles. mp 242°-243° C.

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