Synthesis And Chiral Recognitionof Helical Poly(phenylacetylene)s Bearing L-Chg-OH Derivatives Pendants

Helical poly(phenylacetylene)is a kind of dynamic helical polymer,which has the conjugated structure with single double bond.It has excellent properties in the fields of electricity,optics and biology.In this work,helical poly(phenylacetylene)derivatives bearing L-Cyclohexyl-Gly-OH(L-Chg-OH)as pendants were synthesized.Chiroptical properties and their chiral recognition ability of chiral stationary phases(CSPs)for HPLC were investigated.Phenylacetylene monomers bearing L-Cyclohexyl-Gly-OH group were synthesized via Sonagashira coupling reaction,elimination,eaterification,and amidation reaction,named as N-(4-ethynylbenzoyl)-L-cyclohexylglycinol(PAA-Chg-ol)and N-(4-ethynylbenzoyl)-L-cyclohexylglycine(PAA-Chg),respectively.Then four phenylacetylene monomers with carbamate group were synthesized via the reaction between isocyanate and the active hydroxyl of PAA-Chg-ol,including two monomers with one chiral center PAA-Chg-3,5DMPC,PAA-Chg-3,5DCPC and two chiral centres PAA-Chg-(S)MPC,PAA-Chg-(R)MPC.The polymer action of those monomers was in DMF using a Rh(nbd)BPh4 as the catalyst to yield the poly(phenylacetylene)s:PPAA-Chg,PPAA-Chg-ol,PPAA-Chg-3,5DMPC,PPPAA-Chg-3,5DCPC,PPAA-Chg-(S)MPC,PPAA-Chg-(R)MPC.The structure of monomers and polymers were characterized by IR,NMR and SEC,the results indicated the main-chain of polymers possessed cis-transoid configuration.The polymers were investigated via polarimeter and circular dichroism(CD)spectra,the results indicated the polymers possess dynamic helical conformation.The corresponding polymer based coated-type CSPs were prepared using suitable solvents,their chiral recognition abilities were investigated by HPLC.The results showed that:rac-17 Omeprazole was separated completely on CSP-Chg-ol,rac-8 Binaphthol was separated completely on CSP-Chg-(R)-MPC.Polar solvents(chloroform and tetrahydrofuran)were introduced into mobile phase CSP-Chg-3,5DMPC,CSP-Chg-(S)MPC,CSP-Chg-(R)MPC during HPLC measurement,research polar solvents on recognition abilities of the CSPs were investigated.The recognition abilities were decreased slightly with the introduction of CHCl3.The chiral recognition abilities were first improved then decreased slightly with the increased content of THF,the separation factor of 14 enantiomer was increased from 1.61 to 2.03 CSP-Chg-(S)MPC when 1%THF was added.