Synthesis Of Chiral Compounds By Magnetic Immobilized Lipase In Ionic Liquids

Magnetic polymer microspheres have been widely used in immobilized enzyme areas because of theirs magnetic response and biocompatible.Ionic liquid is expected to become green solvents replace organic solvents due to their low vapor pressure,high thermal stability and environmental friendliness in the future.Two kinds of magnetic polymer microspheres by suspension polymerization for immobilizing Pseudomonas sp lipase(PSL)and penicillin G acylase(PGA).The immobilized enzyme have achieved synthesis and chiral resolution of 2-aryl-4-hydroxy tetrahydropyrane and 1-substituted-3-hydroxy pyrrolidone in ionic liquid medium,even the high yield synthesis of cefadroxil in ionic liquids aqueous phase cosolvent.The super paramagnetic polymer microspheres were prepared by inverse suspension polymerization for immobilizing Pseudomonas sp lipase with the particle size of microspheres are 200-300 ?m,the specific surface area was 26.32m2/g,the average pore diameter was 41.21 nm,the saturation magnetization was 3.46 emu/g,the content of epoxy groups was 0.55 mmol/g.Racemic 2-(4-chlorophenyl)-4-hydroxy tetrahydropyrane was synthesized by prins cyclization method with 3-butene-3-alcohol and p-chlorobenzaldehyde as raw materials in 1l-butyl-3-methylimidazolium tetrafluoroborate.(2R,4S)-2-(4-chlorophenyl)-4-hydroxy tetrahydropyrane was synthesized via transesterification resolution of 2-(4-chlorophenyl)-4-hydroxy tetrahydropyrane using the magnetic immobilized Pseudomonas sp lipase.Under the optimum reaction conditions of the molar ratio was 1 mmol:0.25 mmol of vinyl acetate to substrate 2-(4-chlorophenyl)-4-hydroxy tetrahydropyrane,at 35? for 12 h,the conversion of 2-(4-chlorophenyl)-4-hydroxy tetrahydropyrane was 49.9%,the enantiomeric excess(ees)of(2R,4S)-2-(4-chlorophenyl)-4-hydroxy tetrahydropyrane was 99.6%and enantiomeric excess(eep)of(2S,4R)-2-(4-chlorophenyl)tetrahydropyrane-4-alcohol acetate was 99.9%.The 2-(4-methyl phenyl)-4-hydroxyl tetrahydropyrane,2-(4-methoxyl phenyl)-4-hydroxyl tetrahydropyrane and 2-phenyl-4-hydroxyl tetrahydropyrane were obtained via transesterification resolution of corresponding racemates under the optimal conditions,and the ees of(2R,4S)-2-(4-methyl phenyl)-4-hydroxyl tetrahydropyrane,(2R,4S)-2-(4-methoxyl phenyl)-4-hydroxyl tetrahydropyrane and(2R,4S)-2-phenyl-4-hydroxyl tetrahydropyrane all up to 99%,the eep of(2S,4R)-2-(4-methyl phenyl)tetrahydropyrane-4-alcohol acetate,(2S,4R)-2-(4-methoxyl phenyl)tetrahydropyrane-4-alcohol acetate and(2S,4R)-2-phenyl tetrahydropyrane-4-alcohol acetate were 92.6%,95%and 78.4%,respectively.The acemic(R,S)-1-benzoyl-3-hydroxy pyrrolidinol was synthesized by using 3-pyrrolidine alcohol and benzoyl chloride as raw materials in 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide.(S)-1-1-benzoy 1-3-hydroxy pyrrolidinol was synthesized via transesterification resolution of(R,S)-1-benzoyl-3-hydroxy pyrrolidinol using the magnetic immobilized Pseudomonas sp lipase.Under the optimum reaction conditions of[Bmim][TNf2]as the reaction medium,0.25 mmol(R,S)-1-benzoyl-3-hydroxy pyrrolidinol,the amount of vinyl acetate was 12 mmol,at 35? for 24h,the conversion of(R,S)-1-benzoyl-3-hydroxy pyrrolidinol was 51.7%,the enantiomeric excess(ees)of(R)-1-benzoyl-3-hydroxy pyrrolidinol was 99.1%and enantiomeric excess(eep)of(S)-1-benzoyl-3-pyrrolidinyl acetate was 95.4%.After 10 times of repeated use,the enantiomeric excess(ees)of(R)-1-benzoyl-3-hydroxy pyrrolidinol was still greater than 95.5%.(R,S)-1-methyl-3-hydroxy pyrrolidinol and(R,S)-1-benzyl-3-hydroxy pyrrolidinol were obtained via transesterification resolution of corresponding racemates under the optimal conditions,and the ees of(S)-1-methyl-3-hydroxy pyrrolidinol and(S)-1-benzyl-3-hydroxy pyrrolidinol all up to 99%,the eep of(S)-1-methyl-3-pyrrolidinyl acetate and(S)-1-benzyl-3-pyrrolidinyl acetate were 92.5%and 85.1%,respectively.The amino functionalized magnetic polymer microspheres MP-NH2 were prepared by dispersion polymerization and characterized by SEM,TEM,XRD,FT-IR and for immobilizing penicillin G acylase in the 1-butyl-3-methylimidazolium hexafluorophosphate.The maximum enzyme loading of immobilized PGA was 515 mg/g,the initial activity was 3166 U/g,after repeated 10 times can maintain the initial enzyme activity of 91.7%.Moreover,the immobilized PGA had better thermal stability and acid base stability than free PGA,and the initial activity of immobilized PGA was about 3.7 times higher than free PGA in the range of 25?-45 ?.The effects of immobilized PGA on synthesis of cefadroxil was investigated in aqueous phase and organic phase,ionic liquids and ionic liquids-phosphate cosolvents medium.The results showed that the yield and mole ratio of synthesis to hydrolysis had significantly improved in[Bmim][TNf2]-phosphate,[Bmim][PF6]-phosphate cosolvents.The optimum conditions were as follows:the volume fraction of ionic liquid was 62.5%,7-ADCA(50mmol/L)and D-HPGM molar ratio of 1:1.8,at 30? for 18 h,yield of cefadroxil was 79%,S/H was 1.12.On this basis,the process of enzyme catalyzed synthesis of cefadroxil by response surface optimization method was optimized,the optimum reaction conditions were as follows:50mmol/L 7-ADCA,90mmol/L D-HPGM,the optimum volume fraction of[Bmim][TNf2]was 64.7%in[Bmim][TNf2]-PBS,at 28.7? for 23.5h,the yield was 79.6%,S/H was 1.19.