Study Of Chemo-enzymatic Approach To The Synthesis Of The Clopidogrel

Clopidogrel is a new platelet aggregation inhibitor,and the treatment effect is clear.Following the term of protection of clopidogrel in China is overdue,it has great economic and realistic significance to get through an excellent process route and realize large-scale commercial utilization.(S)-2-chlorophenyglycine is the key intermediatein the synthesis of clopidogrel.In this dissertation,immobilized penicillin G acylase(PGA)was used in resolution of(R,S)-N-phenylacetyl-2-chlorophenyglycine to achieve(S)-2-chlorophenyglycine,and this approach was developed instead of traditional chemical methods.The(S)-2-chlorophenyglycine takes place nucleophilicsubstitution reaction with 2-(2-thienyl)ethyl toluene-p-sulphonate after methyl esterification to abtain(S)-Methyl-(2-thienylethamino)(2-chlorophenyl)acetate hydrochloride,then synthetize(S)-clopidogrel through cyclization reaction.A chemo-enzymatic approach to the synthesis of the clopidogrel was developed.Through the study on the characters of resolution of(R,S)-N-phenyl acetyl-2-chlorophenyglycine with immobilized PGA,it showed that the immobilized PGA has the highest activity under the conditions of 50?and pH 8.0,and an excellent thermostability at 30?,the half-time is over 40 days,and it also has a excellent storage stability when it was stored under 4?.When under the conditions of 50 ? and pH 8.0,during the catalytic process,kinetics constants were:Km=29.88 mM,Vm=9.82 mM·min-1.Substrate with high concentration(more than 150 mM)displayed inhibitory effect on immobilized PGA,and the inhibition constant was 269.13 mM.(S)-2-chlorophenyglycine showed competitive inhibition while phenylacetic acid showed noncompetitive inhibition.The inhibition constant were 56.92 mM and 39.04 mM,respectively.Packed bed reactor(PBR)was used to produce(S)-2-chlorophenyglycine.When producing in PBR with semi-continous mode,under the better conditions,the conversion of substrate,concentration of(S)-2-chlorophenyglycine,productivity of(S)-2-chlorophenyglycine were 48.03%,38.42 mM,0.024 g/h/(g catalyst),respectively.While with continous mode,the conversion of substrate,concentration of(S)-2-chlorophenyglycine,productivity of(S)-2-chlorophenyglycine were 45.30%,36.24 mM,0.045 g/h/(g catalyst),respectively,under the better conditions.Meanwhile,in packed bed reactor,the stability was very excellent.Thus,compared comprehensively,producing in PBR with continous mode was more suitable for larger scale production.After separating(S)-2-chlorophenyglycine from reactant,(S)-clopidogrel can be synthetized through four steps.(S)-2-chloro-phenyglycine and 2-(2-Thienyl)ethanol were used as raw meterial,through methyl esterification,sulfonylation,nucleophilicsubstitution,cyclization,and salification,(S)-clopidogrel and its sulfate can be obtained.The yields of these steps were 85.0%,80.9%,73.7%,58.0%,respectively.