To a reflux apparatus add 25 g of lidocaine, 60ml of water and 17.5 g of benzyl chloride with stirring and heating in 70-90°C. The solution needs to be heated and stirred in the before given value for 24h, the solution needs to be cooled down to 30°C. The unreacted reagents are removed with 3×10 mL of toluene. With stirring dissolve 65 g of sodium hydroxide into 65 mL of cold water and add it to the aqueous solution with stirring over the course of 3 h. Filter the mixture, wash with some water and dry in open air. Recrystallize in hot chloroform or hot ethanol.
Heating the mixture with vigorous stirring for 24 h
Removal of the unreacted reagents
Addition of the sodium hydroxide solution