Preparation Of Macrocyclic Antibiotics And Their Derivatives Chiral Stationary Phases And Study Of Enantiomers Separation

This dissertation focuses on the enantioseparation using macrocyclic antibioticschiral stationary phases (CSPs) by high performance liquid chromatography (HPLC),including preparation of macrocyclic glycopeptide and its phenyl isocyanatederivatives, enantioseparation of chiral compounds, study of several factorsconcerning chiral separation and discussion of chiral recognition mechanism.In Chapter 1, the importance and methods of chiral separation is brieflyintroduced.In Chapter 2, the literatures of three kinds of CSPs, macrocyclic CSPs,polysaccharide derivative CSPs and Pirkle type CSPs are briefly reviewed.In Chapter 3, two new CSPs, m-methylphenyl isocyanate teicoplanin (MP-TE)and p-chlorophenyl isocyanate teicoplanin (PCl-TE) are synthesized from themacrocyclic glycopeptide teicoptanin CSP(TE), using derivative agents,m-methylphenyl isocyanate or p-chlorophenyl isocyanate. Evaluation and comparisonof these three TE-based CSPs are processed with 16 recemates under RP (reversedphase) and PO (polar organic) mode, respectively. The chromatographic results aregiven as the retention, selectivity, resolution factors and the enantioselective freeenergy difference corresponding to the separation of the two enantiomers. The effectof pH, organic modifier type and amount are discussed, and the stereoselectivity forthree TE-based CSPs are compared. The retention forα-amino acids on these threeCSPs follow the direction:TE＞PCl-TE＞MP-TE, while chiral selectivity andresolution follow the direction: MP-TE＞PCl-TE＞TE. Compare TE with eachderivative CSP, 1 compound (10%) (oxazapam) gets better separation on TE and 9(90%) gets better on MP-TE CSP; all compounds get better separation on PCl-TECSP, under RP mode. 6 amino alcohols are enantioseparated on three TE-based CSPsunder PO mode. The influence of the amount and the ratio of the acid/alkali on theenantioseparation are investigated. The retentions for amino alcohols of these threeCSPs follow the direction:PC1-TE＞MP-TE＞TE and the selectivities of these threeCSPs show great differences. MP-TE CSP is the most unfavorable CSP for enantiosepation ofβ-blockers using PO mobile phase. Compare TE with PC1-TE CSP,4β-blockers(67%) get better enantiomeric separation on PCl-TE and 2(33%) getbetter on TE CSP, under PO mode.In Chapter 4, HPLC enantiomeric separations of 19 racemic analytes, 8 aminoacids and 11 non amino acids, are evaluated using chiral stationary phases (CSPs)based on the macrocyclic glycopeptides teicoplanin (TE), phenylisocyanateteicoplanin (Phe-TE), and 3, 5-dimethylphenylisocyanate teicoplanin (DMP-TE) intwo different mobile phase modes, i.e., the RP mode and the PO mode. The Phe-TEand the DMP-TE CSPs are synthesized from the TE using derivative agents, phenylisocyanate or 3, 5-dimethylphenyl isocyanate. The chromatographic results are givenas the retention, selectivity, and resolution factors and the enantioselective free energydifference corresponding to the. separation of the two enantiomers. The effect of pH,organic modifier type and amount are discussed, and the stereoselectivity for threeTE-based CSPs are compared. The chiral selectivity forα-amino acids of these threeCSPs follows the direction: DMP-TE＞Phe-TE＞TE. Compare TE with each derivativeCSP, 6 compounds(55%) get better separation on Phe-TE and 5(45%) better on TECSP; 7 compounds(64%) get better separation on DMP-TE and 4(36%) on TE, underRP mode. The TE is the favorable CSP for enantioseparation theβ-blockers using POmobile phase. Comparison of the enantiomeric separations using self-made TE,Phe-TE, and DMP-TE are conducted in order to gain a better understanding of thechiral recognition mechanism of the macrocyclic glycopeptide antibiotics CSRIn Chapter 5, two new CSPs, m-methylphenyl isocyanate vancomycin (MP-Van),and p-chlorophenyl isocyanate vancomycin (PC1-Van) are synthesized from themacrocyclic glycopeptide vancomycin CSP (Van), usingi derivative agents,m-methylphenyl isocyanate or p-chlorophenyl isocyanate. Evaluation and comparisonof these three Van-based CSPs are processed with 3 recemates under PO and NP(Normal phase) mode, respectively. In PO mode, the influence of the ratio and theamount of acid/alkali on the enantioseparion is investigated and the chiral recognitionmechanism is discussed. The weak alkali pharmaceutical lamivudine and itsintermediate retain longer on MP-Van while enantioseparate better on Van CSP. The near-neutral pharmaceutical thalidomide gets greater retention and selectivity both onMP-Van CSR Furthermore, the acid and/or alkali give little influence on itsenantiomeric separation. Under NP mode, three axis chiral analytes are separated onthree Van-based CSPs. The influence of the type and the amount of alcoholicadditives and solute structure on the chiral separation is studied. 2, 2'-dihydroxy-1,1'-binaphthyl can be partly enantioseparated on MP-Van CSR 2, 2'-diamino-1,1'-binaphthyl gets longer retention on MP-Van CSP and better selectivity on Van CSR2-amino-2'-hydroxy-1, 1'-binaphthyl gets greater retention and selectivity both onMP-Van CSP.In Chapter 6, conditions for separation of isomers of a self-prepared mandelicacid derivative, methyl 2-phenyl-2-(tetrahydropyranyloxy) acetate (the analyte)were studied. Because of the presence of two chiral carbons, the analyte consists offour stereoisomers stable at ambient temperature with 2SS-, 2RS-, 2SR-, and2RR-configurations (2SS, the isomer with 2S, 1S-configuration, etc.). Chiral HPLC ofthe analyte results in four peaks, using the (S, S)-Whelk-O1 with the mobile phaseconsisting of hexane and the t-butyl methyl ether (TBME), suggesting that thecolumn is capable of resolving the analyte sufficiently. It is found that TBMEpresence dramatically changed the retention activity of the isomers though it producesthe best enantioseparation on (S, S)-Whelk-O1 chiral column. The amount of TBMEin the mobile phase influences the degree of retention change. The 5% (v/v) TBMEgives the biggest shift compares with concentration 10% (v/v) and 8% (v/v). Underthe same condition, 2-propanol does not produce the same results. The chiralseparation is also tried on cellulose tris (3, 5-dimethylphenylcarbamate) (CDMPC)and gets 3 peaks to four isomers indicating some but not full enantiomer resolution.Achiral HPLC of the analyte results in two well-resolved peaks when analyzed onthe C18 column under RP mode and on the #-porasil column using normal phasemobile phase, respectively. The two peaks correspond to the two enantiomer pairs,2SS/2RR and 2RS/2SR, but with, at this stage, unknown elution order. The achiralseparation is also got on HP-5 column by GC, MS confirmes the structure. The chiral and achiral separations of diastereoisomers 2R and 2S of the analyte areexperimented simultaneously (2R, the diastereoisomer with 2R fixed, etc.).In Chapter 7, the separation of isomers of camptothecin synthetic intermediate,2-[-p-tosyl-(R)-prolinoyl]-2-[6-cyanoyl-(1,1-ethylenedioxy)-5-one-1,2,3,9-quarthydro-indolizine-yl] ethyl butyrate, on O,O'-bis (3,5-dimethylbenzoyl)-N,N'-diallyl-L-tartardiamicle(CHI-DMB) and(R, R)-3,5-dinitrobenzoyl-1,2- diphenylethane-1,2-diamine((R, R)-DNB-DPEDA) chiral columns is got. The influence of the alcoholic modifiersin mobile phase, including kinds and the concentration for the separation is studied.We also investigate the separation mechanism of the analyte on the two chiralcolumns and find that the attractive interactions between the analyte and the CSP playthe predominant role on both CSPs. Consulted from the interactions between theCSP and the analyte, on CHI-DMB' chiral column,π-πstacking, dipole-dipoleinteractions react whileπ-πstacking, dipole-dipole interaction and the hydrogenbonding work on (R, R)-DNB-DPEDA chiral column. Besides these, the steric bulk isalso important for the separation of the isomers of camptothecin syntheticintermediate. A rational correlation is found between elution order and absoluteconfiguration of the analyte. The elution order is confirmed by corresponding isomer.In Chapter 8, direct enantiomeric resolution of two synthesized organicphosphonate derivatives [(2-Chloro-phenylamino)-(2-hydroxy-phenyl)-methyl]phosphonic acid diethyl ester(compound 1)and [(2-Chloro-phenyl)-(4-fluoro-phenyl-amino)-methyl] phosphonic acid diethyl ester(compound 2) have been achieved,using hexane as the mobile phase with various alcohols as modifiers. The influence ofthe mobile phase composition and solute structure on the chiral separation is studied.It is found that compound 1 is achieved well separation on (S,S)-Whelk-O1,CHI-DMB, cellulose tris(3,5-dimethylphenylcarbamate)(CDMPC) and cellulosetrisphenylcarbamate (CTPC) chiral stationary phases while compound 2 could beseparated on (R, R)-DNB- DPEDA and CDMPC chiral stationary phases. The chiralrecognition mechanism of (S, S)-Whelk-O1, (R, R)-DNB-DPEDA and cellulosederivative CSPs is explored. On (S, S)-Whelk-O1 and CHI-DMB CSP, hydrogen-bonding interactions play an important role in chiral recognition. On (R,R)-DNB-DPEDA-CSP, the dipole-dipole interactions andπ-πstacking are importantto chiral discrimination. On (S, S)-Whelk-O1 CSP and (R, R)-DNB-DPEDA CSP, acorrelation is concluded between elution order and absolute configuration of theanalytes. Interestingly, on cellulose derivative CSPs, acidic additive is necessary forenantioseparation of 1 and 2. On cellulose CSPs, the inclusion and fitness of soluteshape in the chiral cavity significantly contributes to the enantioseparation of solutes.Furthermore, as for the enantioseparation 1, the hydrogen-bonding interactions playan important role on CTPC, but play a minor role on CDMPC.In Chapter 9, three high efficiency aryloxyphenoxypropionic acid herbicides,fluazifop, cyhalofop-butyl and diclofop, are enantioseparated on CDMPCsuccessfully. The influence of the mobile phase composition and solute structure onthe chiral separation is studied. Among three aryloxyphenoxypropionic acidherbicides, the cyhalofop-butyl retains longest and diclofop gets the bestenantioseparation indicating that the dipole-dipole interaction orπ-πstacking whichproduced by CN group of the cyhalofop-butyl might benefit to retention but do notcontribute to enantioselectivity. The results also show that the hydrogen-bondinginteractions between the fluazifop and CDMPC play an important role in chiralrecognition. As for diclofop and cyhalofop-butyl, the inclusion and fitness of soluteshape in the chiral cavity contribute to the chiral discrimination dramatically. Inconclusion, the structure of solutes plays a key role in the chiral recognition. Threearyloxyphenoxypropionic acid herbicides are also experimented on vancomycin CSPunder normal phase but the results are not as good as that of on CDMPC. The methodbrings out a technical support for searching for high efficiency and low poisonaryloxyphenoxypropionic acid herbicides.In Chapter 10, the enantiomeric separation of a ferrocene derivative, 3-(1-N,N-dimethyl)-ethyl ferrocene, is got using an amylose tris(3,5-dimethylphenyl-carbamate)(Chiralpak AD) chiral column, under normal phase mode. The influence ofthe mobile phase composition on the chiral separation is studied. Ethanol is the bestalcoholic additive because the twisting of the glucose unit caused by it just fit in with the shape of the solute. The alkali in the mobile phase makes the peak shape betterbut does not good for selectivity. The thermodynamic results show that the interactionbetween the solute and the CSP do not change in the research temperature range(from 15 to 35℃). Furthermore, the values of△△H°. and△△S°are both negative,which indicate this is an enthalpy-driven separation. The increase of the columntemperature is not good for the enantioseparaion. The enantioseparation transitiontemperature T_iso is 601K.