Research On The Synthesis Of Glufosinate And Its Derivatives

Glufosinate is a phosphorus-containing amino acid herbicide with high efficiency,low toxicity,broad spectrum of herbicides.In recent years,with the limitation and ban of some high-efficiency herbicides,glufosinate has become more and more important in organic pesticide market.Its synthesis and process have been the focus of people.At present,the Strecker synthesis process generally adopted in industrial production for its mature,but the need of using highly toxic cyanide will damage people and environment.The 4-hydroxymethylphosphono-2-oxobutanoic acid(referred to as keto acid)synthesizes the glufosinate route,which has the advantages of mild reaction conditions,high conversion rate,low cost,no need to use highly toxic substances,it has a good Industrialization prospects.In addition,currently commercially available glufosinate is a racemate,but only L-type glufosinate has herbicidal activity,while D-type has no pharmacological effect,so the synthesis of L-glufosinate and the resolution of DL-glyphosate also receiving attention.This paper studies the route of synthesizing glufosinate by keto acid.The diacid chloride intermediate is prepared by reacting methylphosphoric acid chloride(MDP)with acrylic acid,and then the bisacyl chloride intermediate is reacted with methanol to obtain a dimethyl ester intermediate,and finally the dimethyl ester intermediate is reacted with diethyl oxalate.The ketone condensation gives the keto acid intermediate.The optimum process conditions in each synthesis stage were studied.The keto acid intermediates synthesized under the optimal conditions were analyzed to have a purity of 96.3% and a yield of 74.6%(based on dimethyl ester intermediates).Secondly,the synthesis of glufosinate derivatives was studied.Two glufosinate derivatives were designed and synthesized,and one derivative,nitroxane(six-membered ring),has not been reported.In this paper,a single crystal of six-membered ring was obtained by experiments,and its structure was confirmed by various characterizations.Another derivative,5-carboxy-2-carbonylmethyl-1,2-azaphosphorus(five-membered ring),was prepared by experiment,and its structure was verified by various characterizations.In addition,the synthesis of the derivative 4-hydroxymethylphosphono-2-oxobutanoic acid was also studied.Finally,the paper studied the resolution of glufosinate racemates.Separation of glufosinate D and L forms was achieved by chemical resolution using(-)quinine as a resolving agent.At the same time,the crystal of D-type glufosinate hydrochloride was obtained and its structure was characterized.