Sodium cyanate (28mmol) in water (25mL) was added to a solution of N-methyl anthranilic acid (20mmol) and acetic acid (0.2mL) in water (50mL) with stirring. When the temperature of the reaction mixture reached 40°C, NaOH was added in portions till the reaction temperature reach to 75°C. Stirring was continued without cooling for 4h, after which the crystals were filtered off and dissolved in boiling water (50mL). The solution was acidified with 50percent HSodium cyanate (30.15 g, 0.46 mol) was added to a slurry of N- methylanthranilic acid (50.0 g, 0.33 mol) in water (1 .75 L) and acetic acid (3.3 mL). The reaction mixture was heated to 50 °C for 1 h. The solution was slowly basified by the addition of sodium hydroxide (exothermic). The resulting solution was heated to 80 °C and stirred overnight. The reaction mixture was cooled to 0 2-(Methylamino)benzoic acid (4.50 g, 0.0300 mol) and acetic acid (0.3 mL) were dissolved in water (158 mL), a solution of sodium isocyanate (2.76 g, 42.0 mmol) in water (54 mL) was added slowly at room temperature. To a stirred mixture of Methyl /V-Methyl anthranilate (1 .46 mL, 10 mmol) in glacial acetic acid (10 mL) was added KOCN (975 mg, 12 mmol) in 3 mL of HUrea (460 mmol) was heated to melt, then 2-methylaminobenzoic acid (46 mmol) was added.
|
|
