Interaction between chiral diols BDPDD, DMBDPD and BINOL with prochiral compounds was examined and some new supramolecular complexes were prepared. It was found that these chiral hosts could include prochiral guests,...Interaction between chiral diols BDPDD, DMBDPD and BINOL with prochiral compounds was examined and some new supramolecular complexes were prepared. It was found that these chiral hosts could include prochiral guests, a, b-unsaturated compounds or piper- azinedione derivatives to give inclusion crystals in different molar ratio. Formations of these supramolecular complexes were characterized by the data of IR and 1H NMR spectra.展开更多
The chemistry of axially chiral compounds has emerged as a subject of increasing interest due to their widespread presence in natural products,bioactive molecules,advanced materials,and chiral ligands/catalysts.On the...The chemistry of axially chiral compounds has emerged as a subject of increasing interest due to their widespread presence in natural products,bioactive molecules,advanced materials,and chiral ligands/catalysts.On the other hand,catalytic asymmetric radical-based transformations provide a complementary platform for the construction of enantiomerically enriched molecules that are in growing demand in the chemical and pharmaceutical in-dustries.In recent years,considerable research efforts have been devoted to the development of catalytic asymmetric radical reactions for the construction of axially chiral compounds based on the unique reactivity modes of diverse radicals.In this review,we critically illustrate these recent achievements according to different radical precursors and catalytic activation modes.Wherever possible,special emphasis is also placed on the discussion of mechanistic features underlying these works and substrate scopes.This review should be of great interest to the experts in this area,but also serve as a helpful starting point for new researchers in this field.展开更多
In this paper,the concept of reversed-or normal-phase chiral stationary phase liquid chromatography has been put forward according to the polar strength of mobile and stationary phases. The statistical model developed...In this paper,the concept of reversed-or normal-phase chiral stationary phase liquid chromatography has been put forward according to the polar strength of mobile and stationary phases. The statistical model developed in HPLC has been used to investigate the separation mechanism of D-and L-enantiomer in chiral stationary phase liquid chromatography.It has been observed that the variation of capacity factor of enantiomers with mobile phase composition in both reversed-phase and normal-phase chiral stationary phase liquid chromatography can be described by the fundamental elution equation lnk'=a+blnC_b+cC_b.The effect of mobile phase composition on the selec- tivity of enantiomers D and L in normal-phase chiral stationary phase liquid chromatography cam be described by the equation lnα=⊿a+⊿blnC_b,but in reversed-phase chiral stationary phase liquid chromatography the selectivity is almost independant of the mobile phase composition.展开更多
Chiral spirocyclic compounds have attracted the attention of scholars and scientists owing to their potential applications in the pharmaceutical industry as either active pharmaceutical ingredients, catalysts in synth...Chiral spirocyclic compounds have attracted the attention of scholars and scientists owing to their potential applications in the pharmaceutical industry as either active pharmaceutical ingredients, catalysts in synthesizing active enantiomers, or as surface modifiers on silica particles to resolve entantiomers. In this study, five spiro compounds of 3,9-diphenyl-2,4,8,10-tetraoxaspiro[5.5]-undecane（1）, 3,9-（4-methoxyphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（2）, 3,9-（4-methylphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（3）, 4,4＇-（2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl）dibenzoic acid（4） and 3,9-di（4-formyl-phenyl）-2,4,8,10-tetraoxa-spiro[5.5]-undecane（5） were synthesized by grinding pentaerythritol with benzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-carboxybenzaldehyde or terephthalaldehyde monoacetal in the presence of InI3r3 under solvent-free conditions. A normal phase HPLC method was successfully developed to resolve entantiomers of compounds 1--5 on a chiral column. Specific optical rotation of R or S entantiomers（1） was determined and the corresponding configurations were proposed based on Lowe＇s rule.展开更多
The physiologically active groups such as purine and pyrimidine bases are introduced to the asymmetric ynthesis. The optically pure compounds bearing purine and pyrimidine bases （5a—5e） were prepared via the asymet...The physiologically active groups such as purine and pyrimidine bases are introduced to the asymmetric ynthesis. The optically pure compounds bearing purine and pyrimidine bases （5a—5e） were prepared via the asymetric Michael addition reaction of purines and pyrimidines as Michael donators with the chiral source 5-（R）-[（1R, 2S, 5R）-menthyloxy]-2（5H）-furanone （3a）, which was prepared from the natural chiral auxiliary （-）-menthol. The synthetic method was studied in detail and the new compounds were identified on the basis of their analytical data and spectroscopic data, such as [α]<sub>D</sub><sup>20</sup>, IR, UV, <sup>1</sup>H NMR, <sup>13</sup>C NMR and MS. The absolute configuration of 5a was established by X-ray crystallography. The results provided an efficient synthetic route to chiral purines and pyrimidine analogues, and offered chiral sources for further research on the physiologically active compounds of chiral nucleotides.展开更多
Asymmetric reductive amination of carbonyl compounds was carried out using a novel class of aliphatic quarternary ammonium based chiral ionic liquid. S-(+)-2,3-dihydroxy-N,N,N-tributylpropanaminum bromide chiral ionic...Asymmetric reductive amination of carbonyl compounds was carried out using a novel class of aliphatic quarternary ammonium based chiral ionic liquid. S-(+)-2,3-dihydroxy-N,N,N-tributylpropanaminum bromide chiral ionic liquid has been synthesized, characterized and used for asymmetric reductive amination of carbonyl compounds in the presence of sodium borohydride. These preliminary results are encouraging and advocate dual role of novel ionic liquid as a medium and reducing agent for proficient conversion of ketones to amines, however, reductive amination reaction needs to be established for other substituents.展开更多
The effects of two chlorinated chiral stationary phases, namely, Lux Cellulose-2 and Lux i-Cellulose-5, flow-rate, percentage of co-solvent and chemical structures of the compounds on retention and resolution were stu...The effects of two chlorinated chiral stationary phases, namely, Lux Cellulose-2 and Lux i-Cellulose-5, flow-rate, percentage of co-solvent and chemical structures of the compounds on retention and resolution were studied within this article. In this work a backpressure of 150 bar, a temperature of 40 ℃ and 10% of methanol as co-solvent were chosen as operating conditions. The optimum flow-rate was 2 mL/min. The percentage of co-solvent was studied between 7.5% and 15%.We have observed that 15% of methanol gave the best results for most of the compounds. For all the derivatives, the Lux Cellulose-2 provided better resolutions going from 1.50 to 3.59 compared with Lux i-Cellulose-5.展开更多
A new compound of general formula {[(H2O)2K(μ-H2O)Sr]@[Cr(C2O4)3]}n (1) has been synthesized in water and characterized by elemental and thermal analyses, EDX, IR and UV-Vis spectroscopies and by single crystal X-ray...A new compound of general formula {[(H2O)2K(μ-H2O)Sr]@[Cr(C2O4)3]}n (1) has been synthesized in water and characterized by elemental and thermal analyses, EDX, IR and UV-Vis spectroscopies and by single crystal X-ray structure determination. Compound 1 crystallizes in the chiral space group Fdd2 of orthorhombic system with a = 14.110 (4) ?, b = 36.074 (11)?, c =11.034 (3)? and Z = 16. Compound 1 is a coordination polymer in which the three-dimensional lattice framework is realized by the interconnectivity between K+ cations, Sr2+ cations, aqua ligands and [Cr(C2O4)3]3– complex anions. The asymmetric unit of 1 consists of one cationic motif formally written [(H2O)2K(μ-H2O)Sr]3+ and one anionic entity, [Cr(C2O4)3]3–. The K+ and Sr2+ ions in the cationic motif are both eight-coordinate while the Cr3+ ions in the anionic complex are six-coordinate in a distorted octahedral geometry. Coulombic interactions between the ionic motifs and the three-dimensional H-bonding involving aqua ligands help to consolidate the bulk structure. Thermogra-vimetric analysis (TGA) shows that compound 1 is stable to heat up to ca. 80℃.展开更多
基金This work was supported by the National Natural Science Foundation of China (Project 29972033) and the Key Science Research Foundation of Hubei Province of China (Project 98IP1305).
文摘Interaction between chiral diols BDPDD, DMBDPD and BINOL with prochiral compounds was examined and some new supramolecular complexes were prepared. It was found that these chiral hosts could include prochiral guests, a, b-unsaturated compounds or piper- azinedione derivatives to give inclusion crystals in different molar ratio. Formations of these supramolecular complexes were characterized by the data of IR and 1H NMR spectra.
基金the NationalNatural Science Foundation of China(Nos.21820102003,91956201,21901081,22171099)the Open Research Fund of the School of Chemistry and Chemical Engineering,the Henan Normal University(No.2021YB02)+1 种基金the Program of Introducing Talents of Discipline to Universities of China(No.B17019)the Excellent Doctoral DissertationCultivation Grant to D.L.from Central China Normal University(CCNU).
文摘The chemistry of axially chiral compounds has emerged as a subject of increasing interest due to their widespread presence in natural products,bioactive molecules,advanced materials,and chiral ligands/catalysts.On the other hand,catalytic asymmetric radical-based transformations provide a complementary platform for the construction of enantiomerically enriched molecules that are in growing demand in the chemical and pharmaceutical in-dustries.In recent years,considerable research efforts have been devoted to the development of catalytic asymmetric radical reactions for the construction of axially chiral compounds based on the unique reactivity modes of diverse radicals.In this review,we critically illustrate these recent achievements according to different radical precursors and catalytic activation modes.Wherever possible,special emphasis is also placed on the discussion of mechanistic features underlying these works and substrate scopes.This review should be of great interest to the experts in this area,but also serve as a helpful starting point for new researchers in this field.
基金This work was supported by the National Natural Science Foundation of China.
文摘In this paper,the concept of reversed-or normal-phase chiral stationary phase liquid chromatography has been put forward according to the polar strength of mobile and stationary phases. The statistical model developed in HPLC has been used to investigate the separation mechanism of D-and L-enantiomer in chiral stationary phase liquid chromatography.It has been observed that the variation of capacity factor of enantiomers with mobile phase composition in both reversed-phase and normal-phase chiral stationary phase liquid chromatography can be described by the fundamental elution equation lnk'=a+blnC_b+cC_b.The effect of mobile phase composition on the selec- tivity of enantiomers D and L in normal-phase chiral stationary phase liquid chromatography cam be described by the equation lnα=⊿a+⊿blnC_b,but in reversed-phase chiral stationary phase liquid chromatography the selectivity is almost independant of the mobile phase composition.
基金the National Natural Science Foundation of China(No.20472064)the Natural Science Foundation of Tian- jin city, China(No.040884311)
文摘Chiral spirocyclic compounds have attracted the attention of scholars and scientists owing to their potential applications in the pharmaceutical industry as either active pharmaceutical ingredients, catalysts in synthesizing active enantiomers, or as surface modifiers on silica particles to resolve entantiomers. In this study, five spiro compounds of 3,9-diphenyl-2,4,8,10-tetraoxaspiro[5.5]-undecane（1）, 3,9-（4-methoxyphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（2）, 3,9-（4-methylphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（3）, 4,4＇-（2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl）dibenzoic acid（4） and 3,9-di（4-formyl-phenyl）-2,4,8,10-tetraoxa-spiro[5.5]-undecane（5） were synthesized by grinding pentaerythritol with benzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-carboxybenzaldehyde or terephthalaldehyde monoacetal in the presence of InI3r3 under solvent-free conditions. A normal phase HPLC method was successfully developed to resolve entantiomers of compounds 1--5 on a chiral column. Specific optical rotation of R or S entantiomers（1） was determined and the corresponding configurations were proposed based on Lowe＇s rule.
基金Project supported by the National Natural Science Foundation of China (Grant No. 29672004)
文摘The physiologically active groups such as purine and pyrimidine bases are introduced to the asymmetric ynthesis. The optically pure compounds bearing purine and pyrimidine bases （5a—5e） were prepared via the asymetric Michael addition reaction of purines and pyrimidines as Michael donators with the chiral source 5-（R）-[（1R, 2S, 5R）-menthyloxy]-2（5H）-furanone （3a）, which was prepared from the natural chiral auxiliary （-）-menthol. The synthetic method was studied in detail and the new compounds were identified on the basis of their analytical data and spectroscopic data, such as [α]<sub>D</sub><sup>20</sup>, IR, UV, <sup>1</sup>H NMR, <sup>13</sup>C NMR and MS. The absolute configuration of 5a was established by X-ray crystallography. The results provided an efficient synthetic route to chiral purines and pyrimidine analogues, and offered chiral sources for further research on the physiologically active compounds of chiral nucleotides.
文摘Asymmetric reductive amination of carbonyl compounds was carried out using a novel class of aliphatic quarternary ammonium based chiral ionic liquid. S-(+)-2,3-dihydroxy-N,N,N-tributylpropanaminum bromide chiral ionic liquid has been synthesized, characterized and used for asymmetric reductive amination of carbonyl compounds in the presence of sodium borohydride. These preliminary results are encouraging and advocate dual role of novel ionic liquid as a medium and reducing agent for proficient conversion of ketones to amines, however, reductive amination reaction needs to be established for other substituents.
基金supported by the State as part of the "Programme d’Investissement d’Avenir",under reference ANR10-IEED-0004-01
文摘The effects of two chlorinated chiral stationary phases, namely, Lux Cellulose-2 and Lux i-Cellulose-5, flow-rate, percentage of co-solvent and chemical structures of the compounds on retention and resolution were studied within this article. In this work a backpressure of 150 bar, a temperature of 40 ℃ and 10% of methanol as co-solvent were chosen as operating conditions. The optimum flow-rate was 2 mL/min. The percentage of co-solvent was studied between 7.5% and 15%.We have observed that 15% of methanol gave the best results for most of the compounds. For all the derivatives, the Lux Cellulose-2 provided better resolutions going from 1.50 to 3.59 compared with Lux i-Cellulose-5.
文摘A new compound of general formula {[(H2O)2K(μ-H2O)Sr]@[Cr(C2O4)3]}n (1) has been synthesized in water and characterized by elemental and thermal analyses, EDX, IR and UV-Vis spectroscopies and by single crystal X-ray structure determination. Compound 1 crystallizes in the chiral space group Fdd2 of orthorhombic system with a = 14.110 (4) ?, b = 36.074 (11)?, c =11.034 (3)? and Z = 16. Compound 1 is a coordination polymer in which the three-dimensional lattice framework is realized by the interconnectivity between K+ cations, Sr2+ cations, aqua ligands and [Cr(C2O4)3]3– complex anions. The asymmetric unit of 1 consists of one cationic motif formally written [(H2O)2K(μ-H2O)Sr]3+ and one anionic entity, [Cr(C2O4)3]3–. The K+ and Sr2+ ions in the cationic motif are both eight-coordinate while the Cr3+ ions in the anionic complex are six-coordinate in a distorted octahedral geometry. Coulombic interactions between the ionic motifs and the three-dimensional H-bonding involving aqua ligands help to consolidate the bulk structure. Thermogra-vimetric analysis (TGA) shows that compound 1 is stable to heat up to ca. 80℃.
