14645-24-0Relevant academic research and scientific papers
A convenient method for the synthesis and resolution of Troeger base
Satishkumar, Sakilam,Periasamy, Mariappan
, p. 1116 - 1119 (2006)
Racemic Troeger base 1 can be readily obtained by the condensation of 4-toluidine and paraformaldehyde in the presence of Lewis acids and easily resolved via the preparation of diastereomeric aggregates using chiral dibenzoyl-l-tartaric acid 2.
Preparation and evaluation of a molecularly imprinted polymer derivatized silica monolithic column for capillary electrochromatography and capillary liquid chromatography
Ou, Junjie,Li, Xin,Feng, Shun,Dong, Jing,Dong, Xiaoli,Kong, Liang,Ye, Mingliang,Zou, Hanfa
, p. 639 - 646 (2007)
A method for preparation of molecularly imprinted polymer (MIP) derivatized onto the surface of a monolithic silica capillary column was successfully developed. The vinyl groups were first introduced onto the silica monolith by immobilization of γ-methacryloxypropyltrimethoxysilane. Then the MIP coating was copolymerized and anchored onto the surface of the silica monolith. Acetonitrile was selected as porogen (solvent). The other preparation conditions, such as monomer concentration, temperature, and time of polymerization, were systematically studied. The obtained MIP-derivatized silica monolith using L-tetrahydropalmatine (L-THP) and (5S,11S)-(-)-Troeger's base (S-TB) as the imprinted template, respectively, was characterized in terms of the retention behavior of thiourea and toluene. Under the optimized CEC conditions, baseline enantioseparations of THP and TB were achieved in 4 min though the effective length of the columns was 8.5 cm. The result indicates that enough recognition sites were on the surface of silica monolith, resulting in strong recognition ability. Compared with a MIP organic monolith, the MIP-derivatized silica monolith exhibits better column efficiency and stability in CEC. Additionally, the comparison of these two kinds of monolithic columns was performed by capillary liquid chromatography. The separation on MIP-derivatized silica monolith was superior to that on the organic monolith.
HPLC with cellulose Tris (3,5-DimethylPhenylcarbamate) chiral stationary phase: Influence of coating times and coating amount on chiral discrimination
Wei, Qiuhong,Su, Hongjiu,Gao, Diannan,Wang, Shudong
, p. 164 - 173 (2019/01/18)
Coating cellulose tris (3,5-dimethylphenylcarbamate) (CDMPC) on silica gels with large pores have been demonstrated as an efficient way for the preparation of chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC). During the process, a number of parameters, including the type of coating solvent, amount of coating, and the method for subsequent solvent removing, have been proved to affect the performance of the resultant CSPs. Coating times and the concentration of coating solution, however, also makes a difference to CSPs' performance by changing the arrangement of cellulose derivatives while remaining the coating amount constant, have much less been studied before, and thereby, were systematically investigated in this work. Results showed that CSPs with more coating times exhibited higher chiral recognition and column efficiency, suggesting that resolution was determined by column efficiency herein. Afterwards, we also investigated the effect of coating amount on the performance of CSPs, and it was shown that the ability of enantio-recognition did not increase all the time as the coating amount; and four of seven racemates achieved best resolution when the coating amount reached to 18.37%. At the end, the reproducibility of CDMPC-coated CSPs were further confirmed by two methods, ie, reprepared the CSP-0.15-3 and reevaluated the effect of coating times.
Preparation and evaluation of regioselectively substituted amylose derivatives for chiral separations
Tang, Shouwan,Jin, Zhaolei,Sun, Baishen,Wang, Fang,Tang, Wenyuan
, p. 512 - 521 (2017/08/26)
Six novel regioselectively substituted amylose derivatives with a benzoate at 2-position and two different phenylcarbamates at 3- and 6-positions were synthesized and their structures were characterized by 1H nuclear magnetic resonance (NMR) spectroscopy. Their enantioseparation abilities were then examined as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) after they were coated on 3-aminopropyl silica gels. Investigations indicated that the substituents at the 3- and 6-positions played an important role in chiral recognition of these amylose 2-benzoate serial derivatives. The derivatives demonstrated characteristic enantioseparation and some racemates were better resolved on these derivatives than on Chiralpak AD, which is one of the most efficient CSPs, utilizing coated amylose tris(3,5-dimethylphenylcarbamate) as the chiral selector. Among the derivatives prepared, amylose 2-benzoate-3-(phenylcarbamate/4-methylphenylcarbamate)-6-(3,5-dimethylphenylcarbamate) exhibited chiral recognition abilities comparable to that of Chiralpak AD and may be useful CSPs in the future. The effect of mobile phase on chiral recognition was also studied. In general, with the decreased concentration of 2-propanol, better resolutions were obtained with longer retention times. Moreover, when ethanol was used instead of 2-propanol, poorer resolutions were often achieved. However, in some cases, improved enantioselectivity was achieved with ethanol rather than 2-propanol as the mobile phase modifier.
Photochemically immobilized 4-methylbenzoyl cellulose as a powerful chiral stationary phase for enantioselective chromatography
Francotte, Eric,Huynh, Dan,Zhang, Tong
, (2016/12/30)
A process to immobilize para-methylbenzoyl cellulose (PMBC) on silica gel has been developed and applied to prepare chiral stationary phases (CSPs) for enantioselective chromatography. The immobilization was achieved by simple irradiation of the polysaccharide derivative with ultraviolet light after coating on a silica gel support. The influence of parameters such as irradiation time and solvent on immobilization effectiveness were investigated. The performance of the prepared immobilized phases were evaluated by injection of a series of racemic compounds onto the packed columns and determination of their chiral recognition ability. By contrast to the classical coated phase, the immobilized CSP can be used under various chromatographic conditions without limitation of organic solvent types as the mobile phase. This extended applicability permits to improve selectivity and to resolve chiral compounds which are not or only poorly soluble in the mobile phases which are compatible with the non-immobilized PMBC stationary phase.
Temperature-triggered switchable helix-helix inversion of poly(phenylacetylene) bearing L-valine ethyl ester pendants and its chiral recognition ability
Zhou, Yanli,Zhang, Chunhong,Qiu, Yuan,Liu, Lijia,Yang, Taotao,Dong, Hongxing,Satoh, Toshifumi,Okamoto, Yoshio
, (2016/12/03)
A phenylacetylene containing the L-valine ethyl ester pendant (PAA-Val) was synthesized and polymerized by an organorhodium catalyst (Rh(nbd)BPh4) to produce the corresponding one-handed helical cis-poly(phenylacetylene) (PPAA-Val). PPAA-Val showed a unique temperature-triggered switchable helix-sense in chloroform, while it was not observed in highly polar solvents, such as N,N′-dimethylformamide (DMF). By heating the solution of PPAA-Val in chloroform, the sign of the CD absorption became reversed, but recovered after cooling the solution to room temperature. Even after six cycles of the heating-cooling treatment, the helix sense of the PPAA-Val's backbone was still switchable without loss of the CD intensity. The PPAA-Val was then coated on silica gel particles to produce novel chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). These novel PPAA-Val based CSPs showed a high chiral recognition ability for racemic mandelonitrile (α = 2.18) and racemic trans-N,N′-diphenylcyclohexane-1,2-dicarboxamide (α = 2.60). Additionally, the one-handed helical cis-polyene backbone of PPAA-Val was irreversibly destroyed to afford PPAA-Val-H by heating in dimethyl sulfoxide (DMSO) accompanied by the complete disappearance of the Cotton effect. Although PPAA-Val-H had the same L-valine ethyl ester pendants as its cis-isomer PPAA-Val, it showed no chiral recognition. It was concluded that the one-handed helical cis-polyene backbone of PPAA-Val plays an important role in the chiral recognition ability.
Synthesis and Enantioseparation Ability of Xylan Bisphenylcarbamate Derivatives as Chiral Stationary Phases in HPLC
Li, Geng,Shen, Jun,Li, Qiang,Okamoto, Yoshio
, p. 518 - 522 (2015/08/03)
Ten novel xylan bisphenylcarbamate derivatives bearing meta- and para-substituents on their phenyl groups were synthesized and their chiral recognition abilities were evaluated as the chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) after coating them on macroporous silica. The chiral recognition abilities of these CSPs depended on the nature, position, and number of the substituents on the phenyl moieties. The introduction of an electron-donating group was more attractive than an electron-withdrawing group to improve the chiral recognition ability of the xylan phenylcarbamate derivatives. Among the CSPs discussed in this study, xylan bis(3,5-dimethylphenylcarbamate)-based CSP seems to possess the highest resolving power for many racemates, and the meta-substituted CSPs showed relatively better chiral recognition than the para-substituted ones. For some racemates, the xylan bis(3,5-dimethylphenylcarbamate) derivative exhibited higher enantioselectivity than the CSP based on cellulose tris(3,5-dimethylphenylcarbamate). Chirality 27:518-522, 2015
Synthesis and chiral recognition ability of a novel fullerene-functionalized cellulose derivative
Gao, Bo,Xu, Zeyu,Fan, Luan,Xu, Xiaodong,Bai, Jianwei,Shen, Xiande
, p. 1479 - 1481 (2015/11/24)
The fullerene-functionalized cellulose derivative 1 was synthesized and coated onto silica gel as chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC). The chiral recognition ability of the obtained chiral packing material (CPM) was evaluated by HPLC with ten types of racemates 2-11. This CPM could be used in the eluents including chloroform and terahydrofuran (THF), which are usually unsuitable solvents for conventional coating-type CPMs. Hence the scope of application of this CPM is wider than conventional coating CPM.
Synthesis of enantiomerically pure Tr?ger's base derivatives via chiral disulfoxides
Ondrisek, Pavol,Schwenk, Rino,Cvengro?, Ján
supporting information, p. 9168 - 9171 (2014/08/05)
The preparation, full characterization and determination of the absolute configuration of diastereomerically pure disulfoxide derivatives of Tr?ger's base are described. A sulfinyl-lithium exchange followed by the reaction with electrophiles affords synth
Influence of stereoregularity and linkage groups on chiral recognition of poly(phenylacetylene) derivatives bearing L -leucine ethyl ester pendants as chiral stationary phases for HPLC
Zhang, Chunhong,Liu, Fangbin,Li, Yufa,Shen, Xiande,Xu, Xiaodong,Sakai, Ryosuke,Satoh, Toshifumi,Kakuchi, Toyoji,Okamoto, Yoshio
, p. 2271 - 2278 (2013/05/09)
Stereoregular poly(phenylacetylene) derivatives bearing L-leucine ethyl ester pendants, poly-1 and poly-2a, were, respectively, synthesized by the polymerization of N-(4-ethynylphenylcarbamoyl)-L-leucine ethyl ester (1) and N-(4-ethynylphenyl-carbonyl)-L-leucine ethyl ester (2) using Rh(nbd)BPh 4 as a catalyst, while stereoirregular poly-2b was synthesized by solid-state thermal polymerization of 2. Their chiral recognition abilities for nine racemates were evaluated as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) after coating them on silica gel. Both poly-1 and poly-2a with a helical conformation showed their characteristic recognition depending on coating solvents and the linkage groups between poly(phenylacetylene) and L-leucine ethyl ester pendants. Poly-2a with a shorter amide linkage showed higher chiral recognition than poly-1 with a longer urea linkage. Coating solvents played an important role in the chiral recognition of both poly-1 and poly-2a due to the different conformation of the polymer main chains induced by the solvents. A few racemates were effectively resolved on the poly-2a coated with a MeOH/CHCl3 (3/7, v/v) mixture. The separation factors for these racemates were comparable to those obtained on the very popular CSPs derived from polysaccharide phenylcarbamates. Stereoirregular poly-2b exhibited much lower chiral recognition than the corresponding stereoregular, helical poly-2a, suggesting that the regular structure of poly(phenylacetylene) main chains is essential to attain high chiral recognition.
