Structure Control And Chiral Recognition Ability Of Optically Active Polymethacrylamide

Optically active poly[?meth?acrylamide]s have been proved to be good chiral stationary phases?CSPs?for high-performance liquid chromatography?HPLC?to separate polar racemates,particularly chiral drugs.The chiral recognition ability of optically active polymethacrylamidesisgreatlyinfluencedbytheirhigher-orderstructure.?R/S?-?+/-?-?-methylbenzylmethacrylamide??R/S?-MPMA?and?3-?triethoxysilyl?propyl?methacryamide?3-T-PMA?have been designed and synthesized in this thesis.Optically active polymers of spatial structure can be obtained by Lewis acid-catalyzed radical polymerization.The proton nuclear magnetic resonance?¹H NMR?and carbon NMR(¹³C NMR)were used to characterize the chemical structure of the monomers and polymers,circular dichroism?CD?and thermogravimetric analysis?TGA?were used to study the optical activity and thermal properties of the polymers,and chiral recognition ability of the polymers as chiral stationary phase?CSP?were evaluated by high performance liquid chromatography?HPLC?with various eluents.The methacrylamide can be polymerized by Lewis acid-catalyzed stereospecific radical polymerization.The data showed that the polar solvents,such as n-butanol and tetrahydrofuran,and the rare earth metal trifluoromethanesulfonate lanthanum can significantly improve the stereoregularity of the polymers,while the monomers'optically active,side group polar,?-methyl group and the Lewis acid's concentration had a certain impact on the stereoregularity of the polymers.The ¹H NMR spectra were used to analyze the interaction between the Lewis acid and the monomer to explore the mechanism of stereocontrol.The copolymer of?R?-?+?-?-methylbenzyl]methacrylamide and?3-?triethoxysilyl?-propyl?methacryamide]was synthesized in methanol and efficiently immobilized onto a silica gel support by intermolecular polycondensation of the triethoxysilyl groups.Proton nuclear magnetic resonance and thermogravimetric analysis were used to calculate the immobilization efficiency.Hexane,2-propanol,chloroform,tetrahydrofuran,dioxane were used as eluent to evaluate the chiral separation ability by HPLC,the obtained CSPs had good chiral recognition ability with the standard eluent consisting of a hexane/2-propanol mixture,the Racemate 9?2,2'-dihydroxy-6,6'-binaphthyl phenyl?can be separated completely with the CSPs.After adding some eluents containing some proportion of chloroform and THF,the separation factor of Racemate 5?1-?9-anthyl?-2,2,2-trifluoroethanol?and Racemate 9 became bigger in the eluent consisting of a hexane/chloroform and hexane/THF,but the separation factor of Racemate 3?benzoin?became smaller.In the case of adding dioxane,the separation factor of the above three racemates got worse in the eluent consisting of a hexane/dioxane,but the eluent time became longer.