N,N-Dimethylbenzylamine → N-(p-sulfophenyl)-cinnamamide

Participants

Reaction Conditions

Reaction Steps

To a suspension of 86.5 g of anhydrous sulphanilic acid in 120 g of acetone are added dropwise, while stirring at 30° C., 168.8 g of N,N-dimethyl-benzylamine in the course of 15 minutes, followed by a solution of 83.5 g of cinnamoyl chloride in 80 g of acetone in the course of 50 minutes. After the addition is complete, the reaction temperature is increased to the reflux temperature for 1 hour, and the acetone is then removed as completely as possible. The residue which remains is stirred for 1 hour at 80° C., 90 g of 50% strength sodium hydroxide solution in 500 ml of water are then added, and the mixture is again heated to 80° C. and left to stand at this temperature for 15 minutes. The phases are separated and the aqueous phase is washed with 50 g of toluene. The aqueous phase, which is still hot, is diluted with 800 ml of water and neutralized with concentrated sulphuric acid. The cooled aqueous solution is then added dropwise in the course of 20 minutes to 1 kg of 50% strength sulphuric acid, while stirring vigorously. The precipitated crystals are separated off and dissolved in 4 liters of water, the solution is filtered, and again brought to crystallization by the addition of 100 g of concentrated sulphuric acid. 111 g of pure N-(p-sulfophenyl)-cinnamamide (corresponding to 75.9% of theory) with a melting point of 235°-237° C. are obtained. UV spectrum (in methanol):

Provenance & Evidence