a, weigh 1g of ethyl p-aminobenzoate in a two-port round-bottomed flask, add 40 ml of acetone to dissolve, then add 3.6g of anhydrous potassium carbonate and 14.1g of iodomethane, the reaction under nitrogen protection at 80 stirring reflux for 24 hours, the reaction is complete, filtration of the reaction solution, take the filtrate, extracted with dichloromethane, the organic phase dewatered with magnesium sulfate, filtration and removal of magnesium sulfate, evaporation and concentration of the product with a The product was separated and purified by chromatographic column (mobile phase dichloromethane: methanol = 20:1) to obtain the product ethyl 4-dimethylaminobenzoate.
b, in step a of the proceeds of 4-dimethylaminobenzoic acid ethyl ester, add 10% sodium hydroxide, not more than the reaction can be, 95% ethanol as a solvent, reflux reaction at 85 C for 6 hours, with 1M hydrochloric acid to adjust the PH to a weak acidic reaction, the reaction solution is concentrated, add anhydrous acetone to dissolve, filtration, take the precipitate, vacuum drying to get 4-dimethylaminobenzoic acid;
