Synthetic method of pregabalin intermediate 2-carboxethyl-3-cyano-5-methylethyl caproate

The invention relates to a synthetic method of pregabalin intermediate 2-carboxethyl-3-cyano-5-methylethyl caproate (CNDE). 2-carboxethyl-5-methyl-2-ethyl hexenoate (ECMH) and sodium hydroxide are firstly mixed in a reaction solvent and then added with hydrocyanic acid, or sodium hydroxide and hydrocyanic acid are firstly mixed in a reaction solvent and then added with the 2-carboxethyl-5-methyl-2-ethyl hexenoate (ECMH), after the reaction is ended, hydrochloric acid is added to regulate the pH value, then water and organic solvent are added for extraction and separation, and the organic phase is washed by using water and then distilled to obtain the 2-carboxethyl-3-cyano-5-methylethyl caproate (CNDE). By adopting the method provided by the invention, the use cost of sodium cyanide is reduced, the wastewater quantity is reduced and the wastewater treatment pressure is relieved.