General procedure for Example 8 N-methyl-N-(4-trifluoromethylphenyl)-1,2-dihydro-4-hydroxy-5-methoxy-1-methyl-2-oxoquinoline-3-carboxamide (Method B): 1,2-dihydro-4-hydroxy-5-methoxy-1-methyl-2-oxoquinoline-3-carboxylic acid (8 g, 0.032 mol) and triethylamine ( 15.5 ml, 0.11 mol) were dissolved in 10 ml of dichloromethane and cooled to 0°C. Within 0.5 h, 150 ml of a dichloromethane solution of thionyl chloride (3.0 ml, 0.042 mol) was added dropwise to this solution while maintaining the temperature at 4°C. After the dropwise addition, stirring was continued at 4°C for 4 hours. After completion of the reaction, the reaction mixture was diluted with 10 ml of dichloromethane and washed sequentially with cold 1 M sulfuric acid and 1 M sodium hydroxide solution. The pH of the aqueous phase was adjusted to 8-8.5, clarified by filtration and acidified with hydrochloric acid to pH 4. Upon standing, a crystalline precipitate was formed, the precipitate was collected by filtration, washed with water and dried to afford the target product 4-hydroxy-5-methoxy-N,1-dimethyl-2-oxo-N-(4-(trifluoromethyl)phenyl)-1,2-dihydroquinoline-3-carboxamide (8.5 g, 65% yield). The product was structurally confirmed by 1H NMR and 13C NMR and analyzed by ESI MS/MS.
