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2015 Volume 26 Issue 3
2015, 26(3): 267-271
doi: 10.1016/j.cclet.2014.11.011
Abstract:
Evodiamine and its derivatives have an asymmetric center at the C13b position. Herein, isomers of evodiamine derivatives 2 and 3 were obtained by straightforward asymmetric total synthesis. Their inhibitory activities toward topoisomerases I and II and their cytotoxicities in cancer cell lines were evaluated. All the four isomers exhibited good to excellent antitumor potency and the (S)-isomers were generally more active than the (R)-isomers. The binding modes of (S)-2 with topoisomerases I and II were also clarified by molecular docking.
Evodiamine and its derivatives have an asymmetric center at the C13b position. Herein, isomers of evodiamine derivatives 2 and 3 were obtained by straightforward asymmetric total synthesis. Their inhibitory activities toward topoisomerases I and II and their cytotoxicities in cancer cell lines were evaluated. All the four isomers exhibited good to excellent antitumor potency and the (S)-isomers were generally more active than the (R)-isomers. The binding modes of (S)-2 with topoisomerases I and II were also clarified by molecular docking.
2015, 26(3): 272-276
doi: 10.1016/j.cclet.2015.01.037
Abstract:
Chlorospermines A and B are biologically interesting acridone natural products and recently isolated from Glycosmis chlorosperma. We report here a convergent approach to construct the tetracyclic core of the natural products. The two fragments are assembled together through Sonogashira coupling, and a cis-triene intermediate was prepared by using hydrosilylation/desilylation. A 6π-electrocyclization/aromatization sequence served as the key step of the synthesis, which formed the tetrasubstituted arene motif in one pot.
Chlorospermines A and B are biologically interesting acridone natural products and recently isolated from Glycosmis chlorosperma. We report here a convergent approach to construct the tetracyclic core of the natural products. The two fragments are assembled together through Sonogashira coupling, and a cis-triene intermediate was prepared by using hydrosilylation/desilylation. A 6π-electrocyclization/aromatization sequence served as the key step of the synthesis, which formed the tetrasubstituted arene motif in one pot.
2015, 26(3): 277-281
doi: 10.1016/j.cclet.2014.12.001
Abstract:
Mesoporous N-doped carbon supported palladium catalyst Pd@CN0.132 was able to efficiently catalyze unprotected indole to indoline under mild conditions. In the aqueous system, a selectivity of 100% and conversion of 96% was achieved under 313 K and atmospheric hydrogen gas.
Mesoporous N-doped carbon supported palladium catalyst Pd@CN0.132 was able to efficiently catalyze unprotected indole to indoline under mild conditions. In the aqueous system, a selectivity of 100% and conversion of 96% was achieved under 313 K and atmospheric hydrogen gas.
2015, 26(3): 282-284
doi: 10.1016/j.cclet.2014.11.026
Abstract:
In this paper, we report a novel approach to the heteroaryl-condensed nuclei of natural furo[3,2-a]carbazole alkaloids. Our synthetic studies use N-phthaloyl tryptophan methyl ester as starting material and zinc ion mediated transamination reaction as the key step. This work also implicated a novel strategy to assemble other [a]-fused carbazoles.
In this paper, we report a novel approach to the heteroaryl-condensed nuclei of natural furo[3,2-a]carbazole alkaloids. Our synthetic studies use N-phthaloyl tryptophan methyl ester as starting material and zinc ion mediated transamination reaction as the key step. This work also implicated a novel strategy to assemble other [a]-fused carbazoles.
2015, 26(3): 285-288
doi: 10.1016/j.cclet.2014.12.003
Abstract:
The influence of ionic surfactants, cetyltrimethylammonium bromide (CTAB), self-assembled within silica-nanochannels of a hybrid mesoporous silica membrane (HMSM) on simple ion transfer (IT) behaviors at the meso-water/1,2-dichloroethane (W/DCE) interface arrays supported by such a HMSM was investigated by voltammetry for the first time. Significantly, it is found that the CTAB in HMSM can dramatically enhance the peak-current responses corresponding to ITs of some anions and even lower their Gibbs transfer energies from W to DCE, which could be ascribed to an anion-exchange process between anions and the bromide of CTAB associated with partial ion-dehydration induced by the CTAB. This work will provide a new strategy to study anion transfer processes and improve the electroanalytical performance for anion detection at the liquid/liquid interface.
The influence of ionic surfactants, cetyltrimethylammonium bromide (CTAB), self-assembled within silica-nanochannels of a hybrid mesoporous silica membrane (HMSM) on simple ion transfer (IT) behaviors at the meso-water/1,2-dichloroethane (W/DCE) interface arrays supported by such a HMSM was investigated by voltammetry for the first time. Significantly, it is found that the CTAB in HMSM can dramatically enhance the peak-current responses corresponding to ITs of some anions and even lower their Gibbs transfer energies from W to DCE, which could be ascribed to an anion-exchange process between anions and the bromide of CTAB associated with partial ion-dehydration induced by the CTAB. This work will provide a new strategy to study anion transfer processes and improve the electroanalytical performance for anion detection at the liquid/liquid interface.
2015, 26(3): 289-292
doi: 10.1016/j.cclet.2014.10.027
Abstract:
In this study, powders of polyethylene oxide (PEO) and lithiumperchlorate (LiClO4) were used as the raw materials for producing the ionic conduction polymer PEO-LiClO4 with different complex-ratios and used for anodic bonding through high energy ball milling method, and meanwhile, X-ray diffraction, differential scanning calorimetry (DSC), ultraviolet absorption spectrum test analysis, and other relevant methods were adopted to research the complexation mechanism of PEO and LiClO4 and the impact of the ionic conduction polymer with different complex-ratios on the anodic bonding process under the action of the strong static electric field. The research results showed that the crystallization of PEO could be effectively obstructed with increased addition of LiClO4, thus increasing the content of PEO-LiClO4 in amorphous area and continuously improving the complexation degree and the room-temperature conductivity thereof, and that the higher room-temperature conductivity enabled PEO-LiClO4 to better bond with metallic aluminum and have better bonding quality. As the new encapsulatingmaterial, such research results will promote the application of new polymer functional materials in micro-electromechanical system (MEMS) components.
In this study, powders of polyethylene oxide (PEO) and lithiumperchlorate (LiClO4) were used as the raw materials for producing the ionic conduction polymer PEO-LiClO4 with different complex-ratios and used for anodic bonding through high energy ball milling method, and meanwhile, X-ray diffraction, differential scanning calorimetry (DSC), ultraviolet absorption spectrum test analysis, and other relevant methods were adopted to research the complexation mechanism of PEO and LiClO4 and the impact of the ionic conduction polymer with different complex-ratios on the anodic bonding process under the action of the strong static electric field. The research results showed that the crystallization of PEO could be effectively obstructed with increased addition of LiClO4, thus increasing the content of PEO-LiClO4 in amorphous area and continuously improving the complexation degree and the room-temperature conductivity thereof, and that the higher room-temperature conductivity enabled PEO-LiClO4 to better bond with metallic aluminum and have better bonding quality. As the new encapsulatingmaterial, such research results will promote the application of new polymer functional materials in micro-electromechanical system (MEMS) components.
2015, 26(3): 293-296
doi: 10.1016/j.cclet.2014.10.023
Abstract:
With the aid of Riemann-Liouville fractional calculus theory, fractional order Savitzky-Golay differentiation (FOSGD) is calculated and applied to pretreat near infrared (NIR) spectra in order to improve the performance of multivariate calibrations. Similar to integral order Savitzky-Golay differentiation (IOSGD), FOSGD is obtained by fitting a spectral curve in a moving window with a polynomial function to estimate its coefficients and then carrying out the weighted average of the spectral curve in the window with the coefficients. Three NIR datasets including diesel, wheat and corn datasets were utilized to test this method. The results showed that FOSGD, which is easy to compute, is a generalmethod to obtain Savitzky-Golay smoothing, fractional order and integral order differentiations. Fractional order differentiation computation to the NIR spectra often improves the performance of the PLS model with smaller RMSECV and RMSEP than integral order ones, especially for physical properties of interest, such as density, cetane number and hardness.
With the aid of Riemann-Liouville fractional calculus theory, fractional order Savitzky-Golay differentiation (FOSGD) is calculated and applied to pretreat near infrared (NIR) spectra in order to improve the performance of multivariate calibrations. Similar to integral order Savitzky-Golay differentiation (IOSGD), FOSGD is obtained by fitting a spectral curve in a moving window with a polynomial function to estimate its coefficients and then carrying out the weighted average of the spectral curve in the window with the coefficients. Three NIR datasets including diesel, wheat and corn datasets were utilized to test this method. The results showed that FOSGD, which is easy to compute, is a generalmethod to obtain Savitzky-Golay smoothing, fractional order and integral order differentiations. Fractional order differentiation computation to the NIR spectra often improves the performance of the PLS model with smaller RMSECV and RMSEP than integral order ones, especially for physical properties of interest, such as density, cetane number and hardness.
2015, 26(3): 297-300
doi: 10.1016/j.cclet.2014.11.014
Abstract:
A microwave-assisted general method for the synthesis of 2-aminovinyl benzimidazoles has been developed. Treatment of the 1,2-phenylenediamines and N-arylated/N,N-dialkylated 3-aminoacroleins with bis(cyclopentadienyl)zirconium(IV) dichloride (Cp2ZrCl2) as the catalyst under microwave irradiation for 3-5 min followed by in situ MnO2 oxidation afforded thirteen 2-aminovinyl benzimidazoles in good yields.
A microwave-assisted general method for the synthesis of 2-aminovinyl benzimidazoles has been developed. Treatment of the 1,2-phenylenediamines and N-arylated/N,N-dialkylated 3-aminoacroleins with bis(cyclopentadienyl)zirconium(IV) dichloride (Cp2ZrCl2) as the catalyst under microwave irradiation for 3-5 min followed by in situ MnO2 oxidation afforded thirteen 2-aminovinyl benzimidazoles in good yields.
Copper-catalyzed 1,3-dipolar cycloaddition of methyleneindolinones and N,N'-cyclic azomethine imines
2015, 26(3): 301-303
doi: 10.1016/j.cclet.2014.11.015
Abstract:
A copper-catalyzed stereoselective 1,3-dipolar cycloaddition of methyleneindolinones and N,N'-cyclic azomethine imines has been developed under mild reaction conditions. The spiro[pyrazolidin-3,3'-oxindoles] were obtained in moderate to high isolated yields (up to 82%) with good stereoselevtivities (up to 15:1) in the presence of 5 mol% of Cu(OAc)2 at room temperature.
A copper-catalyzed stereoselective 1,3-dipolar cycloaddition of methyleneindolinones and N,N'-cyclic azomethine imines has been developed under mild reaction conditions. The spiro[pyrazolidin-3,3'-oxindoles] were obtained in moderate to high isolated yields (up to 82%) with good stereoselevtivities (up to 15:1) in the presence of 5 mol% of Cu(OAc)2 at room temperature.
2015, 26(3): 304-308
doi: 10.1016/j.cclet.2014.12.002
Abstract:
Mesoporous, hollow ZnO microspheres were synthesized via a hydrothermal method, using glycerol and zinc acetate as the starting materials. XRD and FESEM analysis showed that the surface morphology of the spheres with a Wurtzite structure could be reasonably adjusted by varying the weight ratio (Rw) of Zn(CH3COO)2 2H2O:H2O:C3H8O3. The responses of the gas sensor based on the spheres to 100 ppm ethanol and 100 ppm acetone are 18.9 and 10.4, respectively. The response and recovery times of the sensor to ethanol and acetone are 2 s and 3 s, 3 s and 5 s, respectively. The hollow spheres show an intense UV emission at 392 nm and a broad blue-green emission at 488 nm. Interestingly, a light trapping phenomenon is revealed by UV emission and scattering measurements on the microspheres, which can be attributed to the mesoporous shell and hollow structure of the microsphere.
Mesoporous, hollow ZnO microspheres were synthesized via a hydrothermal method, using glycerol and zinc acetate as the starting materials. XRD and FESEM analysis showed that the surface morphology of the spheres with a Wurtzite structure could be reasonably adjusted by varying the weight ratio (Rw) of Zn(CH3COO)2 2H2O:H2O:C3H8O3. The responses of the gas sensor based on the spheres to 100 ppm ethanol and 100 ppm acetone are 18.9 and 10.4, respectively. The response and recovery times of the sensor to ethanol and acetone are 2 s and 3 s, 3 s and 5 s, respectively. The hollow spheres show an intense UV emission at 392 nm and a broad blue-green emission at 488 nm. Interestingly, a light trapping phenomenon is revealed by UV emission and scattering measurements on the microspheres, which can be attributed to the mesoporous shell and hollow structure of the microsphere.
2015, 26(3): 309-312
doi: 10.1016/j.cclet.2014.11.030
Abstract:
1-Sulfopyridinium chloride portrayed as an efficient and recyclable ionic liquid for the synthesis of fused 3,4-dihydropyrimidin-2(1H)-ones and thiones via a modified Biginelli reaction involving one-pot three component condensation of 6-methoxy-1-tetralone, arylaldehydes and urea/thiourea under solventfree conditions. Analytically pure products are formed within 10-20 min in excellent yields.
1-Sulfopyridinium chloride portrayed as an efficient and recyclable ionic liquid for the synthesis of fused 3,4-dihydropyrimidin-2(1H)-ones and thiones via a modified Biginelli reaction involving one-pot three component condensation of 6-methoxy-1-tetralone, arylaldehydes and urea/thiourea under solventfree conditions. Analytically pure products are formed within 10-20 min in excellent yields.
2015, 26(3): 313-316
doi: 10.1016/j.cclet.2014.11.020
Abstract:
Two new prenylated indole alkaloids, namely, dihydrocarneamide A (1) and iso-notoamide B (2), were isolated from the marine-derived endophytic fungus Paecilomyces variotii EN-291. The structures of these metabolites were determined based on comprehensive spectral analysis, together with chiral HPLC analysis of the acidic hydrolysates. Unlike other prenylated indole alkaloids such as asperparalines, notoamides, and versicolamides, compounds 1 and 2 are the rare examples of C-5 prenylation, forming the fused dimethyldihydropyran ring at C-5 and C-6 of the indole ring. The cytotoxic activity of the isolated compounds was evaluated.
Two new prenylated indole alkaloids, namely, dihydrocarneamide A (1) and iso-notoamide B (2), were isolated from the marine-derived endophytic fungus Paecilomyces variotii EN-291. The structures of these metabolites were determined based on comprehensive spectral analysis, together with chiral HPLC analysis of the acidic hydrolysates. Unlike other prenylated indole alkaloids such as asperparalines, notoamides, and versicolamides, compounds 1 and 2 are the rare examples of C-5 prenylation, forming the fused dimethyldihydropyran ring at C-5 and C-6 of the indole ring. The cytotoxic activity of the isolated compounds was evaluated.
2015, 26(3): 317-319
doi: 10.1016/j.cclet.2014.11.027
Abstract:
The aim of this study is to investigate the possible use of a 1,2-dimethylimidazolium ionic liquid, 2,2-bis((1,2-dimethylimidazolium)methyl)propane-1,3-diol hexafluorophosphate (1), as an adsorbent to selectively remove aromatic heterocyclic sulfur compounds from model fuels. The result indicates that adsorbent 1 is insoluble in model fuels. The spent IL saturated sulfur compounds could be regenerated by a water dilution process. The influence of extraction time or temperature as well as the molar ratio of 1 to aromatic heterocyclic sulfur compound was also studied.
The aim of this study is to investigate the possible use of a 1,2-dimethylimidazolium ionic liquid, 2,2-bis((1,2-dimethylimidazolium)methyl)propane-1,3-diol hexafluorophosphate (1), as an adsorbent to selectively remove aromatic heterocyclic sulfur compounds from model fuels. The result indicates that adsorbent 1 is insoluble in model fuels. The spent IL saturated sulfur compounds could be regenerated by a water dilution process. The influence of extraction time or temperature as well as the molar ratio of 1 to aromatic heterocyclic sulfur compound was also studied.
2015, 26(3): 320-322
doi: 10.1016/j.cclet.2015.01.028
Abstract:
A reaction of benzylic alcohols with alkenes has been developed in the presence of bis(trifluoromethane) sulfonimide for the synthesis of trisubstituted alkenes and indane derivatives with high stereoselectivity. In general, benzylic alcohols react with 1,1-diaryl alkenes to afford trisubstituted alkenes, and the reaction with 1,2-disubstituted and trisubstituted alkenes affords indane derivatives through a [3 + 2] annulation reaction.
A reaction of benzylic alcohols with alkenes has been developed in the presence of bis(trifluoromethane) sulfonimide for the synthesis of trisubstituted alkenes and indane derivatives with high stereoselectivity. In general, benzylic alcohols react with 1,1-diaryl alkenes to afford trisubstituted alkenes, and the reaction with 1,2-disubstituted and trisubstituted alkenes affords indane derivatives through a [3 + 2] annulation reaction.
2015, 26(3): 323-328
doi: 10.1016/j.cclet.2014.11.029
Abstract:
In this work, triphenylamine pyridine acetonitrile compounds PyA1, PyA2 and PyA3 are designed and synthesized. They show green fluorescence in water and bright emission in solid state. They have large Strokes shift (about 100 nm). The excitation and emission spectra are investigated in ethyl acetate, chloroform, cyclohexane, ethanol, water, acetonitrile, THF, DMF and DMSO. It is interesting to find that these compounds are able to sense increasing pH values ranging from pH 2 to 7 by showing different color and emission intensities: almost no emission at pH 2 and strong green emission at pH 7. The acid-base switched color and fluorescence changes can be observed under UV irradiation, in water solution and 1% agarose gel. These changes can be repeated for several cycles. We are able to employ these compounds for cell pH environment imaging.
In this work, triphenylamine pyridine acetonitrile compounds PyA1, PyA2 and PyA3 are designed and synthesized. They show green fluorescence in water and bright emission in solid state. They have large Strokes shift (about 100 nm). The excitation and emission spectra are investigated in ethyl acetate, chloroform, cyclohexane, ethanol, water, acetonitrile, THF, DMF and DMSO. It is interesting to find that these compounds are able to sense increasing pH values ranging from pH 2 to 7 by showing different color and emission intensities: almost no emission at pH 2 and strong green emission at pH 7. The acid-base switched color and fluorescence changes can be observed under UV irradiation, in water solution and 1% agarose gel. These changes can be repeated for several cycles. We are able to employ these compounds for cell pH environment imaging.
2015, 26(3): 329-333
doi: 10.1016/j.cclet.2014.11.008
Abstract:
Phosphonates have been frequently used as suitable isosteric and isoelectronic replacements for biologically important phosphates in the development of drugs or drug candidates because of their stability toward the action of phosphatases and other enzymes. In this paper, 12 mono-phosphonate inositol compounds were prepared with phosphonate instead of phosphate by two kinds of strategies, nucleophilic substitution and Arbuzov rearrangement, respectively. All compounds were evaluated in vitro for their activity against non-small cell lung cancer (NSCLC) cell line A549. Two compounds (3ac and 3bb) exhibited good antitumor activity at 10 mg/mL.
Phosphonates have been frequently used as suitable isosteric and isoelectronic replacements for biologically important phosphates in the development of drugs or drug candidates because of their stability toward the action of phosphatases and other enzymes. In this paper, 12 mono-phosphonate inositol compounds were prepared with phosphonate instead of phosphate by two kinds of strategies, nucleophilic substitution and Arbuzov rearrangement, respectively. All compounds were evaluated in vitro for their activity against non-small cell lung cancer (NSCLC) cell line A549. Two compounds (3ac and 3bb) exhibited good antitumor activity at 10 mg/mL.
2015, 26(3): 334-338
doi: 10.1016/j.cclet.2014.11.013
Abstract:
An efficient method has been developed for the synthesis of a series of (20R)-panaxadiol derivatives (4a-w) using a continuous-flow microreactor. The antitumor activities of the newly synthesized compounds were evaluated in vitro in two human prostate adenocarcinoma tumor cell lines (i.e., PC-3 and LNCaP cells), and their cytotoxicities were evaluated using a standard MTT assay. Compounds 4c, 4h, 4p, 4q and 4s exhibited higher antitumor activities toward PC-3 cell line than panaxadiol, which was used as a reference standard.
An efficient method has been developed for the synthesis of a series of (20R)-panaxadiol derivatives (4a-w) using a continuous-flow microreactor. The antitumor activities of the newly synthesized compounds were evaluated in vitro in two human prostate adenocarcinoma tumor cell lines (i.e., PC-3 and LNCaP cells), and their cytotoxicities were evaluated using a standard MTT assay. Compounds 4c, 4h, 4p, 4q and 4s exhibited higher antitumor activities toward PC-3 cell line than panaxadiol, which was used as a reference standard.
2015, 26(3): 339-342
doi: 10.1016/j.cclet.2014.10.028
Abstract:
A new colorimetric and fluorimetric chemosensor for F- detection based on 1H-imidazo[4,5-b]phenazine derivative has been designed and synthesized. It shows excellent fluorescent specific selectivity and sensitivity for F- in DMSO solution. Upon addition of F- to the solution of probe 1, a remarkable color change from yellow to red could be observed easily by the naked-eye. The detection limit of this probe toward F- is 6.2×10-6 mol/L. Analysis by 1H NMR proved that the imidazolyl N-H could be hydrogen-bonded with added fluoride anions, and results in the difference of colors.
A new colorimetric and fluorimetric chemosensor for F- detection based on 1H-imidazo[4,5-b]phenazine derivative has been designed and synthesized. It shows excellent fluorescent specific selectivity and sensitivity for F- in DMSO solution. Upon addition of F- to the solution of probe 1, a remarkable color change from yellow to red could be observed easily by the naked-eye. The detection limit of this probe toward F- is 6.2×10-6 mol/L. Analysis by 1H NMR proved that the imidazolyl N-H could be hydrogen-bonded with added fluoride anions, and results in the difference of colors.
2015, 26(3): 343-347
doi: 10.1016/j.cclet.2014.11.025
Abstract:
A silylated-terpyridine (SiTPy) derivative was newly synthesized and reacted with various transition metal ions in the solutions and self-assembled monolayers (SAMs). Composition and morphology of the SAMs were characterized by using absorption spectra, X-ray photoelectron spectra and atomic force microscope. The silylated-TPy compound gave off a luminescent emission at about 456 nm, which slightly shifted to 452 nm in the Zn2+-SiTPy and Fe2+-SiTPy metalated complexes. The absorbed energy can be further transferred to lanthanide ions (Tb3+ and Eu3+) to give off the typical emissions of the lanthanide complexes together with an emission of the silylated-TPy at about 363 nm.
A silylated-terpyridine (SiTPy) derivative was newly synthesized and reacted with various transition metal ions in the solutions and self-assembled monolayers (SAMs). Composition and morphology of the SAMs were characterized by using absorption spectra, X-ray photoelectron spectra and atomic force microscope. The silylated-TPy compound gave off a luminescent emission at about 456 nm, which slightly shifted to 452 nm in the Zn2+-SiTPy and Fe2+-SiTPy metalated complexes. The absorbed energy can be further transferred to lanthanide ions (Tb3+ and Eu3+) to give off the typical emissions of the lanthanide complexes together with an emission of the silylated-TPy at about 363 nm.
2015, 26(3): 348-352
doi: 10.1016/j.cclet.2014.12.005
Abstract:
To study the synthesis of 3,4-dihydro-2H-3-phenyl-1,3-benzoxazine (benzoxazine), the reaction paths of phenol, aniline and formaldehyde were investigated by analyzing the synthesis crude products. With the aid of high-performance liquid chromatography (HPLC), chromatographic column and preparative HPLC, seven compounds originated from the crude products were obtained and their chemical structures were elucidated. Possible reaction paths are proposed based on these compounds. Results show that Nhydroxymethyl aniline (HMA) derived from the reaction of formaldehyde and aniline is probably the key intermediate during the reaction. HMA can react with itself or other reactants to form other intermediates, such as 1,3,5-triphenyl-1,3,5-triazinane and 2-((phenylamino)methyl)phenol, and further form benzoxazine and byproducts.
To study the synthesis of 3,4-dihydro-2H-3-phenyl-1,3-benzoxazine (benzoxazine), the reaction paths of phenol, aniline and formaldehyde were investigated by analyzing the synthesis crude products. With the aid of high-performance liquid chromatography (HPLC), chromatographic column and preparative HPLC, seven compounds originated from the crude products were obtained and their chemical structures were elucidated. Possible reaction paths are proposed based on these compounds. Results show that Nhydroxymethyl aniline (HMA) derived from the reaction of formaldehyde and aniline is probably the key intermediate during the reaction. HMA can react with itself or other reactants to form other intermediates, such as 1,3,5-triphenyl-1,3,5-triazinane and 2-((phenylamino)methyl)phenol, and further form benzoxazine and byproducts.
2015, 26(3): 353-356
doi: 10.1016/j.cclet.2014.11.009
Abstract:
This work provided the first example of incorporating the oxindole moiety into the Betti bases. The new type of Betti bases were conveniently synthesized in good yields from the three-component reaction of β-naphthol, isatins and cyclic amines, such as piperidine ormorpholine, in methylene dichloride without any other catalyst.
This work provided the first example of incorporating the oxindole moiety into the Betti bases. The new type of Betti bases were conveniently synthesized in good yields from the three-component reaction of β-naphthol, isatins and cyclic amines, such as piperidine ormorpholine, in methylene dichloride without any other catalyst.
2015, 26(3): 357-360
doi: 10.1016/j.cclet.2014.11.012
Abstract:
Benzyl protecting protocol was first employed in two routes for the concise synthesis of dopexamine dihydrochloride. This protecting group could be cleanly removed under mild condition and no unacceptable ion was brought to the final product. The total yield of route I was 43.8% from phenylacetic acid, while it was 54.1% of route II from 2-(3,4-bis(benzyloxy)phenyl)acetic acid. The titration purity of the final product was more than 99.5%, while any single or total impurities met the known standard of the drug by HPLC analysis. The measured residual palladium met an acceptable limit (<1 ppm) as an API for injection.
Benzyl protecting protocol was first employed in two routes for the concise synthesis of dopexamine dihydrochloride. This protecting group could be cleanly removed under mild condition and no unacceptable ion was brought to the final product. The total yield of route I was 43.8% from phenylacetic acid, while it was 54.1% of route II from 2-(3,4-bis(benzyloxy)phenyl)acetic acid. The titration purity of the final product was more than 99.5%, while any single or total impurities met the known standard of the drug by HPLC analysis. The measured residual palladium met an acceptable limit (<1 ppm) as an API for injection.
2015, 26(3): 361-364
doi: 10.1016/j.cclet.2014.11.016
Abstract:
Lipase from Candida sp. 99-125 catalyzed ring-opening polymerization of ε-caprolactone in the presence of 6-mercapto-1-hexanol was presented as a new metal-free approach for direct synthesis of welldefined thiol-terminated poly(ε-caprolactone). Remarkably, high chemoselectivity of lipase from Candida sp. 99-125 toward hydroxyl and thiol was exhibited and quantitative thiol fidelity over 90% was achieved. The tedious protecting/deprotecting steps for thiol and metal residue were avoided. The polymerizations with around 70% monomer conversion were conducted in bulk and toluene at relative low temperature of 40 ℃. Number-average molecular weight of resulted polymers ranged from 3000 to 4700 Da by changing the feed ratio between monomer and initiator. The structures of obtained thiolterminated poly(ε-caprolactone) were demonstrated by combining NMR and SEC analyses.
Lipase from Candida sp. 99-125 catalyzed ring-opening polymerization of ε-caprolactone in the presence of 6-mercapto-1-hexanol was presented as a new metal-free approach for direct synthesis of welldefined thiol-terminated poly(ε-caprolactone). Remarkably, high chemoselectivity of lipase from Candida sp. 99-125 toward hydroxyl and thiol was exhibited and quantitative thiol fidelity over 90% was achieved. The tedious protecting/deprotecting steps for thiol and metal residue were avoided. The polymerizations with around 70% monomer conversion were conducted in bulk and toluene at relative low temperature of 40 ℃. Number-average molecular weight of resulted polymers ranged from 3000 to 4700 Da by changing the feed ratio between monomer and initiator. The structures of obtained thiolterminated poly(ε-caprolactone) were demonstrated by combining NMR and SEC analyses.
2015, 26(3): 365-368
doi: 10.1016/j.cclet.2014.12.019
Abstract:
Cucurbituril has a high symmetry and rigid structure. When cucurbit[6]uril (CB[6]) was nitrolyzed with the mixed solution of acetic anhydride in fuming nitric acid, nitroform (NF) was generated. NF also can be obtained by the nitration of both CB[5,7,8]. This nitration procedure provides a lower risk, inexpensive, new preparation of nitroform, and the reaction condition of this new method is very mild.
Cucurbituril has a high symmetry and rigid structure. When cucurbit[6]uril (CB[6]) was nitrolyzed with the mixed solution of acetic anhydride in fuming nitric acid, nitroform (NF) was generated. NF also can be obtained by the nitration of both CB[5,7,8]. This nitration procedure provides a lower risk, inexpensive, new preparation of nitroform, and the reaction condition of this new method is very mild.
2015, 26(3): 369-372
doi: 10.1016/j.cclet.2014.12.006
Abstract:
A novel method for achieving a copper(II)-catalyzed domino reaction for the construction of 2-aryl quinazolinones, without the addition of any ligand and additive, has been developed. The domino reaction achieved N-(α-substituted)benzylation, benzylic C-H amidation, and C-C (or C-H) bond cleavage.
A novel method for achieving a copper(II)-catalyzed domino reaction for the construction of 2-aryl quinazolinones, without the addition of any ligand and additive, has been developed. The domino reaction achieved N-(α-substituted)benzylation, benzylic C-H amidation, and C-C (or C-H) bond cleavage.
2015, 26(3): 373-376
doi: 10.1016/j.cclet.2014.12.004
Abstract:
Amino acids were found to be as good ligands for copper-catalyzed borylation reactions of primary and secondary alkyl halides, and the B2pin2 acted as bi-boron source for borylation. The high reaction efficiency and mild conditions make the new catalyst system a useful alternative to the recently developed methods for the preparation of alkylboronic esters.
Amino acids were found to be as good ligands for copper-catalyzed borylation reactions of primary and secondary alkyl halides, and the B2pin2 acted as bi-boron source for borylation. The high reaction efficiency and mild conditions make the new catalyst system a useful alternative to the recently developed methods for the preparation of alkylboronic esters.
2015, 26(3): 377-381
doi: 10.1016/j.cclet.2014.11.018
Abstract:
Four recoverable and reusable ionic liquids based on 1,4-diazobicyclo[2.2.2]octane (DABCO) have been synthesized to catalyze the aza-Michael addition of secondary amines to α,β-unsaturated compounds. Among the catalysts tested, [DABCO-PDO][OAc] was found to be most suitable for the reaction of a wide range of cyclic substrates without any solvent at room temperature, and afford the products in good to excellent yields within an appropriate amount of time. The proposed mechanism for the dual activation of the catalyst was supported by experimental results as well as the DFT calculation. In addition, the ionic liquids used can be regenerated and recycled several times without any loss of activity.
Four recoverable and reusable ionic liquids based on 1,4-diazobicyclo[2.2.2]octane (DABCO) have been synthesized to catalyze the aza-Michael addition of secondary amines to α,β-unsaturated compounds. Among the catalysts tested, [DABCO-PDO][OAc] was found to be most suitable for the reaction of a wide range of cyclic substrates without any solvent at room temperature, and afford the products in good to excellent yields within an appropriate amount of time. The proposed mechanism for the dual activation of the catalyst was supported by experimental results as well as the DFT calculation. In addition, the ionic liquids used can be regenerated and recycled several times without any loss of activity.
2015, 26(3): 382-386
doi: 10.1016/j.cclet.2014.10.025
Abstract:
The 3-morpholin-4-yl-propyl-ammine tetrafluoroborate (MPA+) (BF4-) (1) and the 3-morpholin-4-ylpropyl-ammine perchlorate (MPA+) (ClO4-) (2) were synthesized and separated as colorless block crystal. The (MPA+) (BF4-) undergoes a reversible phase transition at ca. 347.3 K with a hysteresis of 16.1 K. Dielectric measurement also can confirm the transition. The crystal structure determined at 300 K (monoclinic, P21/c, a = 9.978(2)Å, b= 7.5206(15)Å, c= 15.058(3)Å, β= 96.99(3)°, v= 1121.6(4)Å3, z= 4) and 373 K (triclinic, P-1, a = 10.021(7) Å,b = 7.662(3) Å, c= 7.920(4) Å, α= 95.012(14)°, β= 101.67(4)°, γ= 91.48(3)°, v= 592.7(6) Å3, z= 2) reveal that this compound has two phase. The most distinct is the BF4- anion is disorder at 373 K, which is probably the driving force of the phase transition. DSC measurement, dielectric measurement and the crystal structure of the compound 2 did not change at 300 K and 100 K.
The 3-morpholin-4-yl-propyl-ammine tetrafluoroborate (MPA+) (BF4-) (1) and the 3-morpholin-4-ylpropyl-ammine perchlorate (MPA+) (ClO4-) (2) were synthesized and separated as colorless block crystal. The (MPA+) (BF4-) undergoes a reversible phase transition at ca. 347.3 K with a hysteresis of 16.1 K. Dielectric measurement also can confirm the transition. The crystal structure determined at 300 K (monoclinic, P21/c, a = 9.978(2)Å, b= 7.5206(15)Å, c= 15.058(3)Å, β= 96.99(3)°, v= 1121.6(4)Å3, z= 4) and 373 K (triclinic, P-1, a = 10.021(7) Å,b = 7.662(3) Å, c= 7.920(4) Å, α= 95.012(14)°, β= 101.67(4)°, γ= 91.48(3)°, v= 592.7(6) Å3, z= 2) reveal that this compound has two phase. The most distinct is the BF4- anion is disorder at 373 K, which is probably the driving force of the phase transition. DSC measurement, dielectric measurement and the crystal structure of the compound 2 did not change at 300 K and 100 K.
2015, 26(3): 387-392
doi: 10.1016/j.cclet.2014.11.017
Abstract:
Wu-tou-tang was applied to treat rheumatoid arthritis, rheumatic arthritis, and joint pain for thousands of years. Aconiti Radix Cocta is the primary component of Wu-tou-tang, and Aconiti Radix and Pinelliae Rhizoma is one of the famous combination taboos in traditional Chinese medicine. A urinary metabonomics method based on the ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) had been established to quantify the changes of the endogenous metabolites in the urine of adjuvant-induced arthritis rats treated by Wutou-tang and Wu-tou-tang and Pinelliae Rhizoma (WP) co-decoctions. There was a clear separation between Wu-tou-tang and WP co-decoction treated groups in the PCA model. 16 potential biomarkers had been identified which correlated with how Pinelliae Rhizoma influenced the therapeutic effect made by Wu-tou-tang. Results showed that it could reduce the therapeutic effects or make some side effects when Pinelliae Rhizoma is added in Wu-tou-tang. This is the first time to usemetabonomics to investigate the reason of combination taboo.
Wu-tou-tang was applied to treat rheumatoid arthritis, rheumatic arthritis, and joint pain for thousands of years. Aconiti Radix Cocta is the primary component of Wu-tou-tang, and Aconiti Radix and Pinelliae Rhizoma is one of the famous combination taboos in traditional Chinese medicine. A urinary metabonomics method based on the ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) had been established to quantify the changes of the endogenous metabolites in the urine of adjuvant-induced arthritis rats treated by Wutou-tang and Wu-tou-tang and Pinelliae Rhizoma (WP) co-decoctions. There was a clear separation between Wu-tou-tang and WP co-decoction treated groups in the PCA model. 16 potential biomarkers had been identified which correlated with how Pinelliae Rhizoma influenced the therapeutic effect made by Wu-tou-tang. Results showed that it could reduce the therapeutic effects or make some side effects when Pinelliae Rhizoma is added in Wu-tou-tang. This is the first time to usemetabonomics to investigate the reason of combination taboo.
