Preparation of Ethyl L-serinate hydrochloride: To a three-necked flask equipped with a condenser tube, an off-gas absorber and an inlet device, add redistilled anhydrous ethanol (100 ml). Dry hydrogen chloride was passed for 1 hour to saturate the anhydrous ethanol with respect to the hydrogen chloride. It was then cooled in an ice bath, 3.5 g of serine was added, and stirring was continued in the ice bath by passing hydrogen chloride for 1 hour. The ice bath was removed and heated to reflux for half an hour. Cool, add 10 grams of anhydrous magnesium sulfate and dry for 24 hours. Filter off the desiccant, evaporate half of the solvent, refrigerator standing overnight, precipitation of colorless crystals, filtration, vacuum drying, and finally get a colorless crystalline product Ethyl L-serinate hydrochloride. Melting point: 160160.8, literature value 159162.
