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2020 Volume 40 Issue 8
2020, 40(8): 2185-2194
doi: 10.6023/cjoc202005017
Abstract:
Free radical reactions represent an efficient and significant tool to construct organic molecules by taking advantages of the high-efficiency, remarkable selectivity and good functional groups tolerance. Lewis-base boryl radicals are a class of species that possess unique structures and chemical reactivity, and a variety of synthetic applications have been developed. This account summarizes the research advances in this research field mainly contributed by our group. The results include Lewis-based boryl radicals enabled borylation reactions, Lewis-based boryl radicals-catalyzed new reactions, and Lewis-based boryl radicals promoted reduction reactions. These reactions feature mild reaction conditions, good functional groups compatibility, high yields, and excellent chemo-, regio-, and stereo-selectivities.
Free radical reactions represent an efficient and significant tool to construct organic molecules by taking advantages of the high-efficiency, remarkable selectivity and good functional groups tolerance. Lewis-base boryl radicals are a class of species that possess unique structures and chemical reactivity, and a variety of synthetic applications have been developed. This account summarizes the research advances in this research field mainly contributed by our group. The results include Lewis-based boryl radicals enabled borylation reactions, Lewis-based boryl radicals-catalyzed new reactions, and Lewis-based boryl radicals promoted reduction reactions. These reactions feature mild reaction conditions, good functional groups compatibility, high yields, and excellent chemo-, regio-, and stereo-selectivities.
2020, 40(8): 2195-2207
doi: 10.6023/cjoc202004030
Abstract:
Climate change and depletion of fossil fuels have drawn considerable attention. Considering carbon dioxide is both the dominant greenhouse gas and renewable C1 source, CO2 valorization into valuable chemicals is considered to reconcile the environment benefit and sustainable chemistry development. Unfortunately, the thermodynamic stability and kinetic inertness of CO2 make its chemical transformation challenging. As a consequence, developing highly efficient catalytic systems and synthetic protocols is crucial for CO2 conversion. In recent years, He's group made great progress on strategy design and catalyst development for CO2 conversion. A series novel CO2 conversion strategies are proposed, including CO2 capture and in-situ transformation, hierarchical reductive functionalization of CO2, designing thermodynamically favorable reactions by multi-component cascade reaction and photo-promoted CO2 transformation. Concurrently, the corresponding highly efficient catalytic systems were also developed based on the reaction mechanism and thus CO2 transformation was successfully performed under mild conditions. It is hoped that this review can arouse broad concern on CO2 transformation and spur its further development.
Climate change and depletion of fossil fuels have drawn considerable attention. Considering carbon dioxide is both the dominant greenhouse gas and renewable C1 source, CO2 valorization into valuable chemicals is considered to reconcile the environment benefit and sustainable chemistry development. Unfortunately, the thermodynamic stability and kinetic inertness of CO2 make its chemical transformation challenging. As a consequence, developing highly efficient catalytic systems and synthetic protocols is crucial for CO2 conversion. In recent years, He's group made great progress on strategy design and catalyst development for CO2 conversion. A series novel CO2 conversion strategies are proposed, including CO2 capture and in-situ transformation, hierarchical reductive functionalization of CO2, designing thermodynamically favorable reactions by multi-component cascade reaction and photo-promoted CO2 transformation. Concurrently, the corresponding highly efficient catalytic systems were also developed based on the reaction mechanism and thus CO2 transformation was successfully performed under mild conditions. It is hoped that this review can arouse broad concern on CO2 transformation and spur its further development.
2020, 40(8): 2221-2231
doi: 10.6023/cjoc202003039
Abstract:
Carbon dioxide is a readily available, low-cost, abundant, non-toxic C1 source, which can potentially serve as an ideal building block in synthetic chemistry. Recently, much progress, expecially multi-component reactions (MCRs) has been achieved in construction of carbonyl-containing heterocycles through annulation by using carbon dioxide as carbonyl/carboxyl source. Herein, the advances on the annulation reaction of atmospheric CO2 with N-, and O-nucleophiles for the constructioin of various carbonyl-containing heterocycles, including benzoxazin, cyclic carbamates, lactams, oxazolidine-2, 4-diones are reviewed. In addition, the carboxylation of C-nucleophiles with CO2 toward carboxylic acids is also summarized.
Carbon dioxide is a readily available, low-cost, abundant, non-toxic C1 source, which can potentially serve as an ideal building block in synthetic chemistry. Recently, much progress, expecially multi-component reactions (MCRs) has been achieved in construction of carbonyl-containing heterocycles through annulation by using carbon dioxide as carbonyl/carboxyl source. Herein, the advances on the annulation reaction of atmospheric CO2 with N-, and O-nucleophiles for the constructioin of various carbonyl-containing heterocycles, including benzoxazin, cyclic carbamates, lactams, oxazolidine-2, 4-diones are reviewed. In addition, the carboxylation of C-nucleophiles with CO2 toward carboxylic acids is also summarized.
2020, 40(8): 2232-2253
doi: 10.6023/cjoc202003051
Abstract:
Aggregation-induced emission (AIE) compounds have attracted much attention due to their important potential applications in biological and chemical sensing, luminescent materials, display and other areas. As an important class of functional molecules, organofluorine compounds have been widely studied in areas such as organic chemitry and materials chemistry. The organofluorine compounds with AIE properties are summarized and classified. The currently reported AIE organofluorine compounds include the fluorinated tetraphenylethene (TPE) derivatives, 9, 10-distyrylanthracene (DSA) derivatives, cyanostilbene derivatives, distyrylbenzene derivatives, fluorinated polymers, carborane clusters, room temperature phosphorescent molecules, and some other fluorinated structures. With fluorine atoms in the structures, the stability of the resulting AIE compounds is generally improved, and fluorine atoms often participate in the intermolecular interactions leading to significant changes in the structure of the aggregation state, and hence changes in luminescence properties, for example, emission enhancement, bathochromism or hypsochromism of the emissions, improvement of the emission quantum yield and lifetime. The prospects of the future study are also discussed.
Aggregation-induced emission (AIE) compounds have attracted much attention due to their important potential applications in biological and chemical sensing, luminescent materials, display and other areas. As an important class of functional molecules, organofluorine compounds have been widely studied in areas such as organic chemitry and materials chemistry. The organofluorine compounds with AIE properties are summarized and classified. The currently reported AIE organofluorine compounds include the fluorinated tetraphenylethene (TPE) derivatives, 9, 10-distyrylanthracene (DSA) derivatives, cyanostilbene derivatives, distyrylbenzene derivatives, fluorinated polymers, carborane clusters, room temperature phosphorescent molecules, and some other fluorinated structures. With fluorine atoms in the structures, the stability of the resulting AIE compounds is generally improved, and fluorine atoms often participate in the intermolecular interactions leading to significant changes in the structure of the aggregation state, and hence changes in luminescence properties, for example, emission enhancement, bathochromism or hypsochromism of the emissions, improvement of the emission quantum yield and lifetime. The prospects of the future study are also discussed.
2020, 40(8): 2254-2274
doi: 10.6023/cjoc202003036
Abstract:
Fluorescent organic-inorganic nanocomposites have attracted more and more attention in the fields of chemical and biological sensing, biological imaging, energy materials, etc., due to their simple preparation, good biocompatibility and excellent imaging performance. Fluorescence quenching often occurs when traditional fluorescent organic small molecules are combined with inorganic materials, however, organic molecules with aggregation-induced emission (AIE) properties, which show high luminescence quantum yields in the aggregated state, provide opportunities for fluorescent organic-inorganic nanocomposites. Because of the unique advantages of the AIE fluorophore-functionalized inorganic nanomaterials, a great deal of research has been carried out on the design, synthesis and applications of such composite materials. The recent progress in the organic-inorganic composites of AIE-active organic small molecules and various types of inorganic nanomaterials (metal nanoparticles, perovskites, layered materials, oxides and sulfides, etc.) is summarized. In particular, the typical applications of these nanocomposites in chemical sensing, biosensing, bioimaging, drug transport, catalysis, photothermal therapy and energy materials are summarized. The prospects of these AIE-active organic-inorganic nanocomposites are also discussed.
Fluorescent organic-inorganic nanocomposites have attracted more and more attention in the fields of chemical and biological sensing, biological imaging, energy materials, etc., due to their simple preparation, good biocompatibility and excellent imaging performance. Fluorescence quenching often occurs when traditional fluorescent organic small molecules are combined with inorganic materials, however, organic molecules with aggregation-induced emission (AIE) properties, which show high luminescence quantum yields in the aggregated state, provide opportunities for fluorescent organic-inorganic nanocomposites. Because of the unique advantages of the AIE fluorophore-functionalized inorganic nanomaterials, a great deal of research has been carried out on the design, synthesis and applications of such composite materials. The recent progress in the organic-inorganic composites of AIE-active organic small molecules and various types of inorganic nanomaterials (metal nanoparticles, perovskites, layered materials, oxides and sulfides, etc.) is summarized. In particular, the typical applications of these nanocomposites in chemical sensing, biosensing, bioimaging, drug transport, catalysis, photothermal therapy and energy materials are summarized. The prospects of these AIE-active organic-inorganic nanocomposites are also discussed.
2020, 40(8): 2275-2289
doi: 10.6023/cjoc202002006
Abstract:
Arylphosphonates and their derivatives are an important class of molecules because of their broad application in medicinal chemistry, material chemistry and organic catalysis. On basis of various aryl sources for the Ar-P bond construction, the recent advances in the development of the synthesis of arylphosphonates catalyzed by transition metals and photoinduced are surveyed.
Arylphosphonates and their derivatives are an important class of molecules because of their broad application in medicinal chemistry, material chemistry and organic catalysis. On basis of various aryl sources for the Ar-P bond construction, the recent advances in the development of the synthesis of arylphosphonates catalyzed by transition metals and photoinduced are surveyed.
2020, 40(8): 2290-2307
doi: 10.6023/cjoc202004024
Abstract:
Heteroarenes are widely found in synthetic drugs and natural products and exhibit various biological activities. Among them, alkylated heteroarenes play a crucial role in the pharmaceutical industry, and have attracted great attention of synthetic chemists. C(sp3)-H bond cleavage strategy was widely used in radical alkylation of heteroarenes in organic synthesis and has been successfully applied in the total synthesis of natural products and pharmaceuticals due to its excellent atom economy. Based on the different precursor compounds (ethers, alcohols, amines, esters, amides and common alkanes), the research progress of radical alkylation of heteroarenes in a decade is summarized, and the related mechanism is also discussed.
Heteroarenes are widely found in synthetic drugs and natural products and exhibit various biological activities. Among them, alkylated heteroarenes play a crucial role in the pharmaceutical industry, and have attracted great attention of synthetic chemists. C(sp3)-H bond cleavage strategy was widely used in radical alkylation of heteroarenes in organic synthesis and has been successfully applied in the total synthesis of natural products and pharmaceuticals due to its excellent atom economy. Based on the different precursor compounds (ethers, alcohols, amines, esters, amides and common alkanes), the research progress of radical alkylation of heteroarenes in a decade is summarized, and the related mechanism is also discussed.
2020, 40(8): 2308-2321
doi: 10.6023/cjoc202003006
Abstract:
Hydroformylation is considered one of the most important homogenously catalyzed processes in dustry. Hydroformylation has been widely used in the production of aldehydes, and aldehydes can also be further converted into high value-added alcohols, acids and other derivatives. Compared with the homogeneous reaction, the heterogeneous catalysts present significant advantages in terms of recyclability, separation of catalysts and products and so on. In recent years, organic polymer-supported rhodium catalysts have shown excellent catalytic activity, high selectivity, and good recycleability in heterogeneous hydroformylation, and have attracted widespread attention. The research progress of the application of organic polymer supported catalysts in hydroformylation is summarized, including synthesis, material characteristics and application of supported catalysts. Finally, the prospect of the reaction is discussed.
Hydroformylation is considered one of the most important homogenously catalyzed processes in dustry. Hydroformylation has been widely used in the production of aldehydes, and aldehydes can also be further converted into high value-added alcohols, acids and other derivatives. Compared with the homogeneous reaction, the heterogeneous catalysts present significant advantages in terms of recyclability, separation of catalysts and products and so on. In recent years, organic polymer-supported rhodium catalysts have shown excellent catalytic activity, high selectivity, and good recycleability in heterogeneous hydroformylation, and have attracted widespread attention. The research progress of the application of organic polymer supported catalysts in hydroformylation is summarized, including synthesis, material characteristics and application of supported catalysts. Finally, the prospect of the reaction is discussed.
2020, 40(8): 2322-2337
doi: 10.6023/cjoc202003055
Abstract:
Organic fluorides play an indispensable role in medicine, agricultural chemistry and other fields, among them fluoromethyl functional groups have strong lipophilicity, which can greatly improve the pharmacokinetics properties of drug molecules. Therefore, it is of great value to develop various fluorination reactions, especially to introduce monofluoromethyl into molecules in fluorination chemistry. The research progress of the monofluoromethylation of different structural molecules is summarized according to the classification of fluoromethyl reagents, and the possible mechanism of some reactions is discussed.
Organic fluorides play an indispensable role in medicine, agricultural chemistry and other fields, among them fluoromethyl functional groups have strong lipophilicity, which can greatly improve the pharmacokinetics properties of drug molecules. Therefore, it is of great value to develop various fluorination reactions, especially to introduce monofluoromethyl into molecules in fluorination chemistry. The research progress of the monofluoromethylation of different structural molecules is summarized according to the classification of fluoromethyl reagents, and the possible mechanism of some reactions is discussed.
2020, 40(8): 2338-2352
doi: 10.6023/cjoc202002010
Abstract:
N-Sulfonyl-1, 2, 3-triazole, an important class of five-membered nitrogen-containing organic compounds, has been found processing widespread application in the synthesis of various nitrogen-containing organic compounds, especially heterocyclic or amino-substituted aromatic rings. The synthetic methods of N-sulfonyl-1, 2, 3-triazole are introduced. Besides, the progress on constructions of various organic compounds via ring-opening reaction of N-sulfonyl-1, 2, 3-triazoles as precursor of α-diazoimine and Rh-carbene imine intermediates in the past two years is reviewed.
N-Sulfonyl-1, 2, 3-triazole, an important class of five-membered nitrogen-containing organic compounds, has been found processing widespread application in the synthesis of various nitrogen-containing organic compounds, especially heterocyclic or amino-substituted aromatic rings. The synthetic methods of N-sulfonyl-1, 2, 3-triazole are introduced. Besides, the progress on constructions of various organic compounds via ring-opening reaction of N-sulfonyl-1, 2, 3-triazoles as precursor of α-diazoimine and Rh-carbene imine intermediates in the past two years is reviewed.
2020, 40(8): 2353-2373
doi: 10.6023/cjoc202003045
Abstract:
Electron-rich alkynes, in which an electron-donating atom or group is attached to the triple bond, have been widely used as versatile building blocks in organic synthesis, due to their unique chemical reactivity. As an important part of electron-rich alkyne chemistry, the addition reaction between electron-rich alkynes and carboxylic acids received considerable attention these years, and various investigations and advances have been reported. The progress of addition reactions between electron-rich alkynes and carboxylic acids is summarized, and the future perspective is prospected.
Electron-rich alkynes, in which an electron-donating atom or group is attached to the triple bond, have been widely used as versatile building blocks in organic synthesis, due to their unique chemical reactivity. As an important part of electron-rich alkyne chemistry, the addition reaction between electron-rich alkynes and carboxylic acids received considerable attention these years, and various investigations and advances have been reported. The progress of addition reactions between electron-rich alkynes and carboxylic acids is summarized, and the future perspective is prospected.
2020, 40(8): 2208-2220
doi: 10.6023/cjoc202002032
Abstract:
Industrial processes of fixing carbon dioxide (CO2) lag far behind the carbon emission generated by human activity. Since CO2 is an abundant, non-toxic, and cost-effective one carbon source, it is highly desirable to develop methodologies on converting CO2 into valuable products for sustainable purpose. Based on the mechanistic insight of CO2 activation by transition-metal catalyst and organocatalyst, a variety of efficient asymmetric CO2 chemical fixation processes have been developed in recent years. This review discusses the advances of enantioselective synthesis of small molecules by asymmetric catalytic reactions with CO2. The interaction between catalyst, CO2 and substrate has been elaborated aiming to inspire the design of new catalytic systems for asymmetric CO2 transformation.
Industrial processes of fixing carbon dioxide (CO2) lag far behind the carbon emission generated by human activity. Since CO2 is an abundant, non-toxic, and cost-effective one carbon source, it is highly desirable to develop methodologies on converting CO2 into valuable products for sustainable purpose. Based on the mechanistic insight of CO2 activation by transition-metal catalyst and organocatalyst, a variety of efficient asymmetric CO2 chemical fixation processes have been developed in recent years. This review discusses the advances of enantioselective synthesis of small molecules by asymmetric catalytic reactions with CO2. The interaction between catalyst, CO2 and substrate has been elaborated aiming to inspire the design of new catalytic systems for asymmetric CO2 transformation.
2020, 40(8): 2374-2386
doi: 10.6023/cjoc202001021
Abstract:
22 novel camphor-based thiosemicarbazone derivatives were synthesized using camphor-based thiosemicarbazone as material and their structures were determined by 1H NMR, 13C NMR and HRMS. The crystal structure of 2-(3-(pyridin-4-ylmethylene)-1, 7, 7-trimethylbicyclo[2.2.1]heptan-2-ylidene)hydrazinecarbothioamide (3n) was determined by single crystal X-ray diffraction. The derivatives were screened in vitro for anticancer activities against human breast cancer cell line (MDA-MB-231), human lung adenocarcinoma cell line (A549), human multiple myeloma cell line (RPMI-8226) and toxicity against a normal human cell line (GES-1) by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS). It was found that majority of the tested analogs showed moderate to significant antitumor activity against selected cancer cell lines. Noticeably, 2-(3-(anthracen-9-ylmethylene)-1, 7, 7-trimethylbicyclo[2.2.1]heptan-2-ylidene)-hydrazinecarbothioamide (3s) exhibited selective anti-tumor activities against MDA-MB-231 cells (IC50=3.90±0.04 μmol·L-1) and low toxicity to GES-1 cells (IC50>50 μmol·L-1). In the process of exploring the underlying mechanism of 3s, it was found that compound 3s could cause G2 phase arrest and apoptosis in MDA-MB-231 cells by overproduction of intracellular reactive oxygen species and collapse of mitochondrial membrane potential. The measured results were confirmed by western blot assay.
22 novel camphor-based thiosemicarbazone derivatives were synthesized using camphor-based thiosemicarbazone as material and their structures were determined by 1H NMR, 13C NMR and HRMS. The crystal structure of 2-(3-(pyridin-4-ylmethylene)-1, 7, 7-trimethylbicyclo[2.2.1]heptan-2-ylidene)hydrazinecarbothioamide (3n) was determined by single crystal X-ray diffraction. The derivatives were screened in vitro for anticancer activities against human breast cancer cell line (MDA-MB-231), human lung adenocarcinoma cell line (A549), human multiple myeloma cell line (RPMI-8226) and toxicity against a normal human cell line (GES-1) by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS). It was found that majority of the tested analogs showed moderate to significant antitumor activity against selected cancer cell lines. Noticeably, 2-(3-(anthracen-9-ylmethylene)-1, 7, 7-trimethylbicyclo[2.2.1]heptan-2-ylidene)-hydrazinecarbothioamide (3s) exhibited selective anti-tumor activities against MDA-MB-231 cells (IC50=3.90±0.04 μmol·L-1) and low toxicity to GES-1 cells (IC50>50 μmol·L-1). In the process of exploring the underlying mechanism of 3s, it was found that compound 3s could cause G2 phase arrest and apoptosis in MDA-MB-231 cells by overproduction of intracellular reactive oxygen species and collapse of mitochondrial membrane potential. The measured results were confirmed by western blot assay.
2020, 40(8): 2411-2418
doi: 10.6023/cjoc202003049
Abstract:
An efficient Cu-CuFe2O4 nanoparticle-catalyzed protodeboronation strategy has been developed for the chemoselective 1, 4-reduction of α, β, γ, δ-unsaturated ketones, carboxylic ester and cyano-ester. This protocol has the advantageous of the use of alcohol as hydrogen source and solvent, low catalyst loading (0.5 mol%), and excellent catalyst recyclability. Additionally, the Cu-CuFe2O4 catalyst has shown excellent performance in gram-scale reactions. Furthermore, the catalytic mechanism has also been discussed. The reactivity of (E)-γ, δ-unsaturated carbonyl products, an important class of γ, δ-unsaturated alkenes, enables easy access to 3-buten-1-ols, 3-buten-1-amines, γ-keto acids, cyclic ethers, and cyclic nitrones.
An efficient Cu-CuFe2O4 nanoparticle-catalyzed protodeboronation strategy has been developed for the chemoselective 1, 4-reduction of α, β, γ, δ-unsaturated ketones, carboxylic ester and cyano-ester. This protocol has the advantageous of the use of alcohol as hydrogen source and solvent, low catalyst loading (0.5 mol%), and excellent catalyst recyclability. Additionally, the Cu-CuFe2O4 catalyst has shown excellent performance in gram-scale reactions. Furthermore, the catalytic mechanism has also been discussed. The reactivity of (E)-γ, δ-unsaturated carbonyl products, an important class of γ, δ-unsaturated alkenes, enables easy access to 3-buten-1-ols, 3-buten-1-amines, γ-keto acids, cyclic ethers, and cyclic nitrones.
2020, 40(8): 2419-2425
doi: 10.6023/cjoc202003038
Abstract:
A silver-catalyzed functionalization of 1-bromoalkynes for the highly regio-and stereo-selective synthesis of (Z)-β-bromo-1-arylvinyl aryl esters was developed. In the presence of Ag2O as a catalyst, and Et3N as a base, the reactions of 1-bromoalkynes with commercially available aromatic carboxylic acids underwent smoothly to afford the corresponding (Z)-β-bromo-1-arylvinyl aryl esters in good yields. The investigation indicates that Ag2O plays an important role in the reaction.
A silver-catalyzed functionalization of 1-bromoalkynes for the highly regio-and stereo-selective synthesis of (Z)-β-bromo-1-arylvinyl aryl esters was developed. In the presence of Ag2O as a catalyst, and Et3N as a base, the reactions of 1-bromoalkynes with commercially available aromatic carboxylic acids underwent smoothly to afford the corresponding (Z)-β-bromo-1-arylvinyl aryl esters in good yields. The investigation indicates that Ag2O plays an important role in the reaction.
2020, 40(8): 2426-2432
doi: 10.6023/cjoc201912036
Abstract:
A simple and efficient method for the preparation of 5H-benzo[d]tetrazolo[5, 1-b] [1 , 3 ]thiazines has been developed. The transformation involved the copper(I)-catalyzed cascade bicyclization of o-alkenylphenyl isothiocyanates with sodium azide to afford corresponding products in moderate to good yields. This present strategy provides an effective way to construct small molecular N-, and S-heterocycles.
A simple and efficient method for the preparation of 5H-benzo[d]tetrazolo[5, 1-b] [
2020, 40(8): 2433-2441
doi: 10.6023/cjoc202001007
Abstract:
An efficient Dess-Martin periodinane (DMP)-promoted dearylation of N-arylsulfonamides was developed through a highly selective oxidative cleavage of the inert C(aryl)-N bonds in secondary sulfonamides while leaving the S-N bond unchanged. This metal-free reaction proceeds under mild conditions and provides access to various biologically important primary sulfonamides, some of which are otherwise unattainable using conventional aminolysis and hydrolysis methods. The concise and efficient dearylation reaction provides the use of an aryl group as a removable protecting sulfonamide group under metal catalyst-free conditions.
An efficient Dess-Martin periodinane (DMP)-promoted dearylation of N-arylsulfonamides was developed through a highly selective oxidative cleavage of the inert C(aryl)-N bonds in secondary sulfonamides while leaving the S-N bond unchanged. This metal-free reaction proceeds under mild conditions and provides access to various biologically important primary sulfonamides, some of which are otherwise unattainable using conventional aminolysis and hydrolysis methods. The concise and efficient dearylation reaction provides the use of an aryl group as a removable protecting sulfonamide group under metal catalyst-free conditions.
2020, 40(8): 2442-2449
doi: 10.6023/cjoc202004009
Abstract:
Elevated homocysteine (Hcy) has been considered as a risk factor for vascular and renal diseases. Therefore, the development of Hcy-specific fluorescent probes, especially ratiometric fluorescent probes is of great importance. In the present study, a highly Hcy selective ratiometric fluorescent probe 3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methyl-benzaldehyde (BA), based on an ortho-hydroxy aldehyde functionalized benzothiazole, is presented. The probe responded selectively to Hcy over other tested species including Cys and GSH with ratiometric fluorescence changes. The probe possessed itself green fluorescence (λem=544 nm). Addition of Hcy to the BA solution triggered remarkable blue fluorescence (λem=478 nm). The fluorescence intensity ratios (I478 nm/I544 nm) were linearly related to the amounts of Hcy from 0 to 1.0 mmol/L with a detection limit of 1.6 μmol/L. The probe BA possessed low cytotoxicity and desirable cell permeability, and could be employed for the ratiometric imaging of Hcy in living cells, suggesting its potential applications in biological systems. Moreover, the sensing mechanism of BA for Hcy was verified by NMR, HRMS and time-dependent density function theory calculations.
Elevated homocysteine (Hcy) has been considered as a risk factor for vascular and renal diseases. Therefore, the development of Hcy-specific fluorescent probes, especially ratiometric fluorescent probes is of great importance. In the present study, a highly Hcy selective ratiometric fluorescent probe 3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methyl-benzaldehyde (BA), based on an ortho-hydroxy aldehyde functionalized benzothiazole, is presented. The probe responded selectively to Hcy over other tested species including Cys and GSH with ratiometric fluorescence changes. The probe possessed itself green fluorescence (λem=544 nm). Addition of Hcy to the BA solution triggered remarkable blue fluorescence (λem=478 nm). The fluorescence intensity ratios (I478 nm/I544 nm) were linearly related to the amounts of Hcy from 0 to 1.0 mmol/L with a detection limit of 1.6 μmol/L. The probe BA possessed low cytotoxicity and desirable cell permeability, and could be employed for the ratiometric imaging of Hcy in living cells, suggesting its potential applications in biological systems. Moreover, the sensing mechanism of BA for Hcy was verified by NMR, HRMS and time-dependent density function theory calculations.
2020, 40(8): 2476-2482
doi: 10.6023/cjoc202002042
Abstract:
Diaryliodonium salts have low toxicity and good stability, and their mediated reactions often have advantages of mild reaction conditions and high selectivity. They have received extensive attention and have been widely used as arylating agents in organic synthesis. A simple and efficient method for the synthesis of 2-arylbenzothiazole derivatives via copper-catalyzed C-H direct arylation of benzothiazoles with diaryliodonium salts as electrophilic arylating reagents was developed. This method shows wide range of substrates, good group tolerance, simple operation and high product yields.
Diaryliodonium salts have low toxicity and good stability, and their mediated reactions often have advantages of mild reaction conditions and high selectivity. They have received extensive attention and have been widely used as arylating agents in organic synthesis. A simple and efficient method for the synthesis of 2-arylbenzothiazole derivatives via copper-catalyzed C-H direct arylation of benzothiazoles with diaryliodonium salts as electrophilic arylating reagents was developed. This method shows wide range of substrates, good group tolerance, simple operation and high product yields.
2020, 40(8): 2502-2507
doi: 10.6023/cjoc202003007
Abstract:
Cysteine is an important biological component of the human body, its levels are related to many diseases. It is especially important to respond quickly and accurately to cysteine concentrations. This study is based on the classical cysteine response mechanism. The thiol group of cysteine undergoes Michael addition to acrylate, and then undergoes intramolecular cyclization to specifically recognize cysteine. A novel ratio-based fluorescent probe was designed and synthesized in this study. The research results found that the probe can specifically recognize cysteine, the detection limit can reach 75 nmol·L-1, can fully respond within 30 min, and has good stability. It exists in cells and has little cytotoxic effects. Therefore, on the basis of solving the problem of poor water solubility, the probe can quickly and accurately analyze the concentration of cysteine in cells, which provides a new means for the study of various diseases and new ideas for the development of chemical materials.
Cysteine is an important biological component of the human body, its levels are related to many diseases. It is especially important to respond quickly and accurately to cysteine concentrations. This study is based on the classical cysteine response mechanism. The thiol group of cysteine undergoes Michael addition to acrylate, and then undergoes intramolecular cyclization to specifically recognize cysteine. A novel ratio-based fluorescent probe was designed and synthesized in this study. The research results found that the probe can specifically recognize cysteine, the detection limit can reach 75 nmol·L-1, can fully respond within 30 min, and has good stability. It exists in cells and has little cytotoxic effects. Therefore, on the basis of solving the problem of poor water solubility, the probe can quickly and accurately analyze the concentration of cysteine in cells, which provides a new means for the study of various diseases and new ideas for the development of chemical materials.
2020, 40(8): 2387-2393
doi: 10.6023/cjoc202003053
Abstract:
Chlorosulfonation of acetanilide was accomplished within 10 min in up to 96% yield via a highly thermoconductive and corrosion-resistant dual-temperature-zone silicon carbide microchannel reactor. The yield of pilot production was up to 92%. In the first stage, low reaction temperature (40℃) was employed to effect a high sulfonation selectivity at the para position of acetanilide. In the second stage, a higher reaction temperature (100℃) led to a faster formation of chlorosulfonation product. To illustrate the application of this reaction, sulfasalazine with antimicrobial and anti-inflammatory activities was synthesized in total yield of 75% via chlorosulfonation, sulfamide formation, hydrolysis under base conditions, diazotization and coupling with salicylic acid. The two-step continuous reaction helped to solve the problems in batch reactor, such as low temperature leading to slow reaction and high temperature resulting byproducts and/or temperature runaway, the safety concern aroused by heat accumulation, and the polution caused by the use of large excess of chlorosulfonic acid in batch production. The above research provides technical support for the large-scale industrial production of p-acetylaminobenzenesulfonyl chloride and its sulfonamides.
Chlorosulfonation of acetanilide was accomplished within 10 min in up to 96% yield via a highly thermoconductive and corrosion-resistant dual-temperature-zone silicon carbide microchannel reactor. The yield of pilot production was up to 92%. In the first stage, low reaction temperature (40℃) was employed to effect a high sulfonation selectivity at the para position of acetanilide. In the second stage, a higher reaction temperature (100℃) led to a faster formation of chlorosulfonation product. To illustrate the application of this reaction, sulfasalazine with antimicrobial and anti-inflammatory activities was synthesized in total yield of 75% via chlorosulfonation, sulfamide formation, hydrolysis under base conditions, diazotization and coupling with salicylic acid. The two-step continuous reaction helped to solve the problems in batch reactor, such as low temperature leading to slow reaction and high temperature resulting byproducts and/or temperature runaway, the safety concern aroused by heat accumulation, and the polution caused by the use of large excess of chlorosulfonic acid in batch production. The above research provides technical support for the large-scale industrial production of p-acetylaminobenzenesulfonyl chloride and its sulfonamides.
2020, 40(8): 2394-2401
doi: 10.6023/cjoc202004019
Abstract:
A practical rhodium-catalyzed highly regioselective ortho-alkenylation of phenolic compound under the assistance of weak coordination center acetoxime ether was developed. This strategy has advantages of simple and mild reaction conditions, wide scope of substrate and high regioselectivity. This protocol provids an efficient and new method for the regioselective ortho-alkenylation of phenols.
A practical rhodium-catalyzed highly regioselective ortho-alkenylation of phenolic compound under the assistance of weak coordination center acetoxime ether was developed. This strategy has advantages of simple and mild reaction conditions, wide scope of substrate and high regioselectivity. This protocol provids an efficient and new method for the regioselective ortho-alkenylation of phenols.
2020, 40(8): 2402-2410
doi: 10.6023/cjoc202003009
Abstract:
A series of 1, 2, 4-triazole-3-sulfide derivatives were designed and synthesized. Their chemical structures were confirmed by 1H NMR, 13C NMR, MS and elemental analysis. The crystal structure of (E)-4-(4-hydroxy-3-methoxyphenyl-methyleneamino)-5-ethyl-4H-1, 2, 4-triazole-3-propylsulfide (1c) was determined by X-ray diffraction analysis. The preliminary assay of neuraminidase (NA, H1N1) inhibitory activity in vitro showed that most of compound 1 has more potent NA inhibitory activity. Among them, compounds (E)-4-(4-hydroxy-3-methoxyphenyl-methyleneamino)-5-ethyl-4H-1, 2, 4-triazole-3-ethylsulfide (1b) and 1c showed the best inhibitory activity with IC50 values of (6.86±2.08) and (9.1±1.56) μg/mL, respectively.
A series of 1, 2, 4-triazole-3-sulfide derivatives were designed and synthesized. Their chemical structures were confirmed by 1H NMR, 13C NMR, MS and elemental analysis. The crystal structure of (E)-4-(4-hydroxy-3-methoxyphenyl-methyleneamino)-5-ethyl-4H-1, 2, 4-triazole-3-propylsulfide (1c) was determined by X-ray diffraction analysis. The preliminary assay of neuraminidase (NA, H1N1) inhibitory activity in vitro showed that most of compound 1 has more potent NA inhibitory activity. Among them, compounds (E)-4-(4-hydroxy-3-methoxyphenyl-methyleneamino)-5-ethyl-4H-1, 2, 4-triazole-3-ethylsulfide (1b) and 1c showed the best inhibitory activity with IC50 values of (6.86±2.08) and (9.1±1.56) μg/mL, respectively.
2020, 40(8): 2450-2459
doi: 10.6023/cjoc201910037
Abstract:
Based on the drug design method of combination of privileged fragments, a series of novel triazolothiadiazole derivatives linked with amino side chain containing urea group were designed as potential DOT1L (disruptor of telomeric silencing 1-like) inhibitors. The intermediate 13 with benzyl chloride on triazolothiadiazole structure was synthesized from aromatic acid through five steps. Under the condition of weak base (DIPEA), the nucleophilic substitution reaction between 13 and amino chain with urea group resulted in triazolothiadiazole derivatives linked with amino side chain containing urea group 15a~15k, while under the condition of strong base (NaH), the new dimeric structure analogues 22a~22d bearing with triazolothiadiazole-triazolothiadiazine were obtained by intermolecular reaction of two molecules of 13. The inhibitory activities of compounds 15 and 22 against DOT1L were tested. The results showed that the tested compounds exhibited moderate or weak DOT1L inhibitory activities at 50 μmol·L-1. Among them, compounds 15k and 22a were the best ones with IC50 values of 25.92 and 10.59 μmol·L-1, respectively, lower than that of the positive control (E)-6-(2-(furan-2-yl)vinyl)-3-phenyl-[1 , 2 , 4 ]triazolo[3, 4-b] [1 , 3 , 4 ]thiadiazole (10). The results of docking experiments suggested that the bulky amino-urea side chain might be the main reason for the loss of the activities of the compounds, which sterically hindered the molecular from binding to the DOT1L enzyme.
Based on the drug design method of combination of privileged fragments, a series of novel triazolothiadiazole derivatives linked with amino side chain containing urea group were designed as potential DOT1L (disruptor of telomeric silencing 1-like) inhibitors. The intermediate 13 with benzyl chloride on triazolothiadiazole structure was synthesized from aromatic acid through five steps. Under the condition of weak base (DIPEA), the nucleophilic substitution reaction between 13 and amino chain with urea group resulted in triazolothiadiazole derivatives linked with amino side chain containing urea group 15a~15k, while under the condition of strong base (NaH), the new dimeric structure analogues 22a~22d bearing with triazolothiadiazole-triazolothiadiazine were obtained by intermolecular reaction of two molecules of 13. The inhibitory activities of compounds 15 and 22 against DOT1L were tested. The results showed that the tested compounds exhibited moderate or weak DOT1L inhibitory activities at 50 μmol·L-1. Among them, compounds 15k and 22a were the best ones with IC50 values of 25.92 and 10.59 μmol·L-1, respectively, lower than that of the positive control (E)-6-(2-(furan-2-yl)vinyl)-3-phenyl-[
2020, 40(8): 2460-2467
doi: 10.6023/cjoc202004038
Abstract:
Chiral pyrrolidine skeletons containing trifluoromethyl group are core structural motifs in many natural products and medicines. As a consequence, extensive studies have been conducted on the exploitation of efficient methods for the asymmetric synthesis of such compounds. In this paper, Ming-Phos/Cu(I)-catalyzed asymmetric intermolecular[3+2] cycloaddition reaction of azomethine ylides and β-trifluoromethyl-α, β-unsaturated ketone was reported. A broad substrate scope was observed with high yield and enantioselectivity (up to 99% yield and 98% ee). The method is featured by its mild conditions, simple operation, easily available ligands and good functional group compatibility.
Chiral pyrrolidine skeletons containing trifluoromethyl group are core structural motifs in many natural products and medicines. As a consequence, extensive studies have been conducted on the exploitation of efficient methods for the asymmetric synthesis of such compounds. In this paper, Ming-Phos/Cu(I)-catalyzed asymmetric intermolecular[3+2] cycloaddition reaction of azomethine ylides and β-trifluoromethyl-α, β-unsaturated ketone was reported. A broad substrate scope was observed with high yield and enantioselectivity (up to 99% yield and 98% ee). The method is featured by its mild conditions, simple operation, easily available ligands and good functional group compatibility.
2020, 40(8): 2468-2475
doi: 10.6023/cjoc202003003
Abstract:
Density functional theory (DFT) calculations were carried out to investigate the mechanism and chemoselectivity of silver-or scandium-catalyzed insertion of diazo compounds into C-C or C-H bonds of 1, 3-dicarbonyl compounds. The results show that silver and scandium carbenes are readily generated by metal-induced extrusion of nitrogen from diazo compounds. When low-coordinated silver(I) is used as the catalyst, carbene insertion into the C-C bond of 1, 3-dicarbonyls leads to 1, 4-dicarbonyl product containing an all-carbon α-quaternary center, through a cascade sequence of electrophilic addition, intramolecular cyclization, selective ring-opening and enol isomerization. When highly coordinated scandium(III) is used, carbene insertion into C-H bond of 1, 3-dicarbonyls leads to 1, 3-dicarbonyl product containing α-tertiary center, through a cascade sequence of electrophilic addition and protonation. Computational studies show that the chemoselectivity results from the cooperative effect of ring tension and the difference in coordination number of metal centers, which provides useful insight into the development of transition metal-catalyzed carbene transfer reactions.
Density functional theory (DFT) calculations were carried out to investigate the mechanism and chemoselectivity of silver-or scandium-catalyzed insertion of diazo compounds into C-C or C-H bonds of 1, 3-dicarbonyl compounds. The results show that silver and scandium carbenes are readily generated by metal-induced extrusion of nitrogen from diazo compounds. When low-coordinated silver(I) is used as the catalyst, carbene insertion into the C-C bond of 1, 3-dicarbonyls leads to 1, 4-dicarbonyl product containing an all-carbon α-quaternary center, through a cascade sequence of electrophilic addition, intramolecular cyclization, selective ring-opening and enol isomerization. When highly coordinated scandium(III) is used, carbene insertion into C-H bond of 1, 3-dicarbonyls leads to 1, 3-dicarbonyl product containing α-tertiary center, through a cascade sequence of electrophilic addition and protonation. Computational studies show that the chemoselectivity results from the cooperative effect of ring tension and the difference in coordination number of metal centers, which provides useful insight into the development of transition metal-catalyzed carbene transfer reactions.
2020, 40(8): 2483-2490
doi: 10.6023/cjoc201912045
Abstract:
Generation of highly active manganese dioxide in situ by using catalytic amount of potassium permanganate in anhydrous ethanol system, the catalytic system promoted S-S bond construction by free radical self coupling reactions of thiophenol and mercaptan compounds at room temperature. 14 disulfides were obtained with 70%~99% yields. At the same time, it was also found that the catalytic system could also catalyze radical cross-coupling reactions between symmetric disulfides and different substituents of thiophenols, thiols, or two different symmetric disulfides, 13 asymmetric disulfides were obtained with 19%~72% yields. The protocol offered the advantages of simple and efficient, easy separation, green solvent, wide range of substrate applications, and mild conditions. All products were confirmed by 1H NMR and 13C NMR spectra.
Generation of highly active manganese dioxide in situ by using catalytic amount of potassium permanganate in anhydrous ethanol system, the catalytic system promoted S-S bond construction by free radical self coupling reactions of thiophenol and mercaptan compounds at room temperature. 14 disulfides were obtained with 70%~99% yields. At the same time, it was also found that the catalytic system could also catalyze radical cross-coupling reactions between symmetric disulfides and different substituents of thiophenols, thiols, or two different symmetric disulfides, 13 asymmetric disulfides were obtained with 19%~72% yields. The protocol offered the advantages of simple and efficient, easy separation, green solvent, wide range of substrate applications, and mild conditions. All products were confirmed by 1H NMR and 13C NMR spectra.
2020, 40(8): 2491-2501
doi: 10.6023/cjoc202004011
Abstract:
During our previous research using natural product phenazine-1-carboxylic acid as the lead compound to develop new pesticides, the phenazine-1-methanol had been found to exhibit excellent fungicidal activity. According to the above fact, a new class of phenazine-1-aryl(5-pyrimidine)methanol derivatives were designed and synthesized by using phenazine-1-methanol as a secondary lead compound, and referring to ergosterol biosynthesis inhibitor fenarimol. The bio-assays showed that compounds 6a~6p displayed moderate fungicidal activities against Thanatephorus cucumeris and Phytophthora capsici. An interesting result is that the fungicidal activities of some of the target compounds against Phenazine-1-carboxylic-Acid (PCA) specific spectrum Thanatephorus cucumeris are greatly reduced, while against fenarimol characteristic spectrum wheat powdery mildew (Erysiphe graminis) retain moderate or strong control effects. The above bio-assays results indicated the mode of action of compounds 6a~6p may be different from that of PCA, but similar to fenarimol. Therefore, further ergosterol biosynthesis inhibition experiment proved that the target compounds had the same mode of action as commercially available fungicide fenarimol.
During our previous research using natural product phenazine-1-carboxylic acid as the lead compound to develop new pesticides, the phenazine-1-methanol had been found to exhibit excellent fungicidal activity. According to the above fact, a new class of phenazine-1-aryl(5-pyrimidine)methanol derivatives were designed and synthesized by using phenazine-1-methanol as a secondary lead compound, and referring to ergosterol biosynthesis inhibitor fenarimol. The bio-assays showed that compounds 6a~6p displayed moderate fungicidal activities against Thanatephorus cucumeris and Phytophthora capsici. An interesting result is that the fungicidal activities of some of the target compounds against Phenazine-1-carboxylic-Acid (PCA) specific spectrum Thanatephorus cucumeris are greatly reduced, while against fenarimol characteristic spectrum wheat powdery mildew (Erysiphe graminis) retain moderate or strong control effects. The above bio-assays results indicated the mode of action of compounds 6a~6p may be different from that of PCA, but similar to fenarimol. Therefore, further ergosterol biosynthesis inhibition experiment proved that the target compounds had the same mode of action as commercially available fungicide fenarimol.
2020, 40(8): 2508-2512
doi: 10.6023/cjoc202004037
Abstract:
A novel fluorescent probe L for Pb2+ based phenanthroline derivative has been designed and synthesized. The probe L displayed fluorescence quenching emission excellent sensitivity specific toward Pb2+ ion. The introduction of Pb2+ resulted the quenching fluorescence of probe L and the color of the solution can be observed changes from yellow to orange in DMF-H2O (V:V=1:1, 10 mmol/L Tris, pH=7.4). The detection limit was as low as 2.68×10-7 mol/L. The bonding mechanism was confirmed by UV-vis, fluorescence, HRMS, 1H NMR experiments and theoretical calculation. It was found that the probe had excellent reversibility for detection of Pb2+ and could be used to effectively identify Pb2+ in living cells.
A novel fluorescent probe L for Pb2+ based phenanthroline derivative has been designed and synthesized. The probe L displayed fluorescence quenching emission excellent sensitivity specific toward Pb2+ ion. The introduction of Pb2+ resulted the quenching fluorescence of probe L and the color of the solution can be observed changes from yellow to orange in DMF-H2O (V:V=1:1, 10 mmol/L Tris, pH=7.4). The detection limit was as low as 2.68×10-7 mol/L. The bonding mechanism was confirmed by UV-vis, fluorescence, HRMS, 1H NMR experiments and theoretical calculation. It was found that the probe had excellent reversibility for detection of Pb2+ and could be used to effectively identify Pb2+ in living cells.
2020, 40(8): 2513-2519
doi: 10.6023/cjoc202001027
Abstract:
Recently, electrochromic devices based on donor-acceptor (D-A) type conjugated polymers have received great attention, owing to their fast response rate, tunable color, good cycle stability, and so on. Two novel donor-acceptor-donor (D-A-D) type monomers N-(4-(5-(4-(diphenylamino)phenyl)-2, 3-dimethylquinoxalin-8-yl)phenyl)-N-phenylbenzenamine (Q1) and N-(4-(6-(4-(diphenylamino)phenyl)-1, 2, 3, 4-tetrahydrophenazin-9-yl)phenyl)-N-phenylbenzenamine (Q2) using triphenylamine as electron donor and quinoxaline-based moiety as electron acceptors were designed, which were further electrochemical polymerized to prepare D-A type electrochromic polymers poly(N-(4-(5-(4-(diphenylamino)phenyl)-2, 3-dimethyl-quinoxalin-8-yl)phenyl)-N-phenylbenzenamine) (PQ1) and poly(N-(4-(6-(4-(diphenylamino)phenyl)-1, 2, 3, 4-tetrahydrophe-nazin-9-yl)phenyl)-N-phenylbenzenamine) (PQ2), respectively. The as-prepared D-A type polymers exhibited pale yellow in the neutral state, and multicolor change with the increase of the applied potentials. These novel electrochromic materials showed fast switch rate, good cycle stability as well as good coloration efficiency. Moreover, the highest contrast ratio of both exceeded 70% around 780 nm, which guaranteed their potential practical applications.
Recently, electrochromic devices based on donor-acceptor (D-A) type conjugated polymers have received great attention, owing to their fast response rate, tunable color, good cycle stability, and so on. Two novel donor-acceptor-donor (D-A-D) type monomers N-(4-(5-(4-(diphenylamino)phenyl)-2, 3-dimethylquinoxalin-8-yl)phenyl)-N-phenylbenzenamine (Q1) and N-(4-(6-(4-(diphenylamino)phenyl)-1, 2, 3, 4-tetrahydrophenazin-9-yl)phenyl)-N-phenylbenzenamine (Q2) using triphenylamine as electron donor and quinoxaline-based moiety as electron acceptors were designed, which were further electrochemical polymerized to prepare D-A type electrochromic polymers poly(N-(4-(5-(4-(diphenylamino)phenyl)-2, 3-dimethyl-quinoxalin-8-yl)phenyl)-N-phenylbenzenamine) (PQ1) and poly(N-(4-(6-(4-(diphenylamino)phenyl)-1, 2, 3, 4-tetrahydrophe-nazin-9-yl)phenyl)-N-phenylbenzenamine) (PQ2), respectively. The as-prepared D-A type polymers exhibited pale yellow in the neutral state, and multicolor change with the increase of the applied potentials. These novel electrochromic materials showed fast switch rate, good cycle stability as well as good coloration efficiency. Moreover, the highest contrast ratio of both exceeded 70% around 780 nm, which guaranteed their potential practical applications.
2020, 40(8): 2520-2525
doi: 10.6023/cjoc202003024
Abstract:
At room temperature, a bifunctional phosphine-gold(Ⅰ) catalyst was used to catalyze the nucleophilic addition/cyclization reaction of o-phenylenediamines with alkynes to generate 1, 5-benzodiazepines in one step. The reaction has the advantages of high atomic-economy, simple raw materials, convenient operation and mild reaction conditions.
At room temperature, a bifunctional phosphine-gold(Ⅰ) catalyst was used to catalyze the nucleophilic addition/cyclization reaction of o-phenylenediamines with alkynes to generate 1, 5-benzodiazepines in one step. The reaction has the advantages of high atomic-economy, simple raw materials, convenient operation and mild reaction conditions.
2020, 40(8): 2526-2530
doi: 10.6023/cjoc202004004
Abstract:
Naphthofuran-4, 9-dione derivatives exhibit a broad spectrum of biological and medicinal activities. The development of green and efficient methods for the synthesis of these heterocyclic compounds is of great importance. In this paper, the N-chloro-succinimide (NCS)-promoted reaction of 2-amino-benzo[g]chromene-3-carbonitriles or ethyl 2-amino-pyrano[3, 2-c]-chromene-3-carboxylates with alcohols lead to the naphthofuran-4, 9-dione or diethyl furo[3, 2-c]chromene-2, 2-dicarboxylate was reported. All reactions were completed in 30 min under room temperature, and two types of novel fused furan derivatives were obtained in 48%~97% yields under tandem ring-opening/cyclization processes.
Naphthofuran-4, 9-dione derivatives exhibit a broad spectrum of biological and medicinal activities. The development of green and efficient methods for the synthesis of these heterocyclic compounds is of great importance. In this paper, the N-chloro-succinimide (NCS)-promoted reaction of 2-amino-benzo[g]chromene-3-carbonitriles or ethyl 2-amino-pyrano[3, 2-c]-chromene-3-carboxylates with alcohols lead to the naphthofuran-4, 9-dione or diethyl furo[3, 2-c]chromene-2, 2-dicarboxylate was reported. All reactions were completed in 30 min under room temperature, and two types of novel fused furan derivatives were obtained in 48%~97% yields under tandem ring-opening/cyclization processes.
2020, 40(8): 2535-2542
doi: 10.6023/cjoc202004020
Abstract:
Thiazole ring is an important five-membered aromatic heterocyclic ring, and its derivatives have various biological activities and are widely used in medicine. The synthesis of 2, 5-diarylthiazole derivatives by acylation, thiolation, cyclization and Heck reaction using inexpensive and readily available substituted benzoic acid as raw materials was developed. The key point was to optimize the Heck reaction conditions and explore the possible reaction mechanism. The method has mild reaction conditions, simple operation, and good substrate universality, which provides a new direction for the synthesis of 2, 5-diaryl substituted thiazoles.
Thiazole ring is an important five-membered aromatic heterocyclic ring, and its derivatives have various biological activities and are widely used in medicine. The synthesis of 2, 5-diarylthiazole derivatives by acylation, thiolation, cyclization and Heck reaction using inexpensive and readily available substituted benzoic acid as raw materials was developed. The key point was to optimize the Heck reaction conditions and explore the possible reaction mechanism. The method has mild reaction conditions, simple operation, and good substrate universality, which provides a new direction for the synthesis of 2, 5-diaryl substituted thiazoles.
2020, 40(8): 2543-2546
doi: 10.6023/cjoc202004029
Abstract:
3, 4-Dihydroxyphenylalanine (DOPA) derivatives inspired by mussels have attracted broad interest in functional coatings of biomaterials and biomedical devices. Fmoc-DOPA(acetonide)-OH is the key precursor for solid-phase synthesis of adhesive mussel proteins and peptides. However, existing synthesis methods of Fmoc-DOPA(acetonide)-OH were tedious and costly which greatly hindered its practical application. Herein, a simple two-step strategy for preparing Fmoc-DOPA-(acetonide)-OH is reported, which is a simple and cost-effective synthesis method with broad application prospects.
3, 4-Dihydroxyphenylalanine (DOPA) derivatives inspired by mussels have attracted broad interest in functional coatings of biomaterials and biomedical devices. Fmoc-DOPA(acetonide)-OH is the key precursor for solid-phase synthesis of adhesive mussel proteins and peptides. However, existing synthesis methods of Fmoc-DOPA(acetonide)-OH were tedious and costly which greatly hindered its practical application. Herein, a simple two-step strategy for preparing Fmoc-DOPA-(acetonide)-OH is reported, which is a simple and cost-effective synthesis method with broad application prospects.
2020, 40(8): 2547-2554
doi: 10.6023/cjoc202004050
Abstract:
In order to improve the fungicidal activity against phytopathogens and enlarge the constructed molecular library, eighteen novel (E)-3-(1-iminoethyl)-5, 5-disubstituted-4-(methylamino)-furan-2(5H)-ones were designed and synthesized based on the diversity-oriented synthesis strategy when the C-4 phenyl group of 3-(1-iminoethyl)-5, 5-disubstituted-4-phenylfuran-2(5H)-one was replaced with the methylamino group. Their structures were characterized by 1H NMR, 13C NMR, HR-MS spectral data. The crystal structure of (E)-3-(1-((4-methoxybenzyloxy)imino)ethyl)-4-(methylamino)-1-oxaspiro[4.5]dec-3-en-2-one (5O) was determined by X-ray diffraction analysis. The bioassay results indicated that all compounds did not exhibit significant in vivo fungicidal activities against phytopathogens, but some of them showed good insecticidal activities against Plutella xylostella, Mythimna seprata and Myzus persicae with 100% mortality at the concentration of 600 μg/mL.
In order to improve the fungicidal activity against phytopathogens and enlarge the constructed molecular library, eighteen novel (E)-3-(1-iminoethyl)-5, 5-disubstituted-4-(methylamino)-furan-2(5H)-ones were designed and synthesized based on the diversity-oriented synthesis strategy when the C-4 phenyl group of 3-(1-iminoethyl)-5, 5-disubstituted-4-phenylfuran-2(5H)-one was replaced with the methylamino group. Their structures were characterized by 1H NMR, 13C NMR, HR-MS spectral data. The crystal structure of (E)-3-(1-((4-methoxybenzyloxy)imino)ethyl)-4-(methylamino)-1-oxaspiro[4.5]dec-3-en-2-one (5O) was determined by X-ray diffraction analysis. The bioassay results indicated that all compounds did not exhibit significant in vivo fungicidal activities against phytopathogens, but some of them showed good insecticidal activities against Plutella xylostella, Mythimna seprata and Myzus persicae with 100% mortality at the concentration of 600 μg/mL.
2020, 40(8): 2555-2562
doi: 10.6023/cjoc202003017
Abstract:
The intramolecular Schmidt reaction of alkyl azides with pentafluorophenyl esters was investigated. The perfluorophenyl 5-azido-2-phenylpentanoate was employed as the model substrate, and the acid promoter, the solvent and the temperature were scanned. Then the titanium tetrachloride in the refluxing 1, 2-dichloroethane was effective for the reaction of perfluorophenyl 5-azido-2-phenylpentanoate. Eleven 5-azido-pentanoates were designed and prepared for exploration, where different aryl, benzyl and alkyl groups were introduced at the α-carbon of perfluorophenyl ester. This type substrate would mainly give isocyanate ion as the primary product from Schmidt rearrangement. Then the scope of substrate was examined, and the experiment results indicated that the substrate with an electron-rich aryl or a benzyl group at the α-carbon of perfluorophenyl ester would afford a lactam via an intramolecular nucleophilic addition of arene to the isocyanate ion, and the substrate with an electron-deficient aryl or an alkyl group at the α-carbon of perfluorophenyl ester would give perfluorophenyl carbamate through an intermolecular capture of isocyanate ion with pentafluorophenol anion. The good leaving apptitude of pentafluorophenol anion should be accounted for inititating the Schmidt reaction, where the nucleophilic attack of azide onto perfluorophenyl ester would proceed very easy.
The intramolecular Schmidt reaction of alkyl azides with pentafluorophenyl esters was investigated. The perfluorophenyl 5-azido-2-phenylpentanoate was employed as the model substrate, and the acid promoter, the solvent and the temperature were scanned. Then the titanium tetrachloride in the refluxing 1, 2-dichloroethane was effective for the reaction of perfluorophenyl 5-azido-2-phenylpentanoate. Eleven 5-azido-pentanoates were designed and prepared for exploration, where different aryl, benzyl and alkyl groups were introduced at the α-carbon of perfluorophenyl ester. This type substrate would mainly give isocyanate ion as the primary product from Schmidt rearrangement. Then the scope of substrate was examined, and the experiment results indicated that the substrate with an electron-rich aryl or a benzyl group at the α-carbon of perfluorophenyl ester would afford a lactam via an intramolecular nucleophilic addition of arene to the isocyanate ion, and the substrate with an electron-deficient aryl or an alkyl group at the α-carbon of perfluorophenyl ester would give perfluorophenyl carbamate through an intermolecular capture of isocyanate ion with pentafluorophenol anion. The good leaving apptitude of pentafluorophenol anion should be accounted for inititating the Schmidt reaction, where the nucleophilic attack of azide onto perfluorophenyl ester would proceed very easy.
2020, 40(8): 2563-2569
doi: 10.6023/cjoc202004016
Abstract:
A novel visible-light-introduced reaction for the construction of benzimidazole derivatives via radical cyclization of o-phenylenediamines with benzonitrile derivatives in water has been developed. The reaction has been achieved in high yield under mild conditions by using Eosin Y as photocatalyst, which is cheap, easy to handle and environmentally friendly. A variety of benzimidazoles were obtained in up to 91% yields. It might provide a promising protocol for the synthesis of benzimidazole derivatives.
A novel visible-light-introduced reaction for the construction of benzimidazole derivatives via radical cyclization of o-phenylenediamines with benzonitrile derivatives in water has been developed. The reaction has been achieved in high yield under mild conditions by using Eosin Y as photocatalyst, which is cheap, easy to handle and environmentally friendly. A variety of benzimidazoles were obtained in up to 91% yields. It might provide a promising protocol for the synthesis of benzimidazole derivatives.
2020, 40(8): 2570-2574
doi: 10.6023/cjoc202003044
Abstract:
Buchwald-Hartwig couplings can modify the pyrimidin-2-amines. Since the pyrimidin-2-amine structures widely exist in medicines, the reaction is of significant industrial application values. The polyaniline-supported copper catalyst (Cu@PANI) was synthesized via the oxidative polymerization of aniline in the presence of copper salt and it could catalyze the Buchwald-Hartwig couplings of pyrimidin-2-amines. Since the nitrogen in polyaniline could well coordinate with copper, the reaction did not require additional ligands and occurred at relatively high catalyst turnover numbers (TONs). As a heterogeneous catalyst, Cu@PANI could be recycled and reused to reduce the cost of catalyst, and meet the requirements of industrial application.
Buchwald-Hartwig couplings can modify the pyrimidin-2-amines. Since the pyrimidin-2-amine structures widely exist in medicines, the reaction is of significant industrial application values. The polyaniline-supported copper catalyst (Cu@PANI) was synthesized via the oxidative polymerization of aniline in the presence of copper salt and it could catalyze the Buchwald-Hartwig couplings of pyrimidin-2-amines. Since the nitrogen in polyaniline could well coordinate with copper, the reaction did not require additional ligands and occurred at relatively high catalyst turnover numbers (TONs). As a heterogeneous catalyst, Cu@PANI could be recycled and reused to reduce the cost of catalyst, and meet the requirements of industrial application.
2020, 40(8): 2575-2582
doi: 10.6023/cjoc202003040
Abstract:
The synthetic route of substituted 1, 2, 4-triazole benzamide derivatives was explored, which included several steps such as catalytic cross-coupling of 2, 6-dichlorobenzonitrile with a triazole, amidation of nitrile, diazotization of amide and hydrolysis, and amidation of acid. Unreported 14 new 1, 2, 4-triazole benzamide derivatives were synthesized. Their chemical structures were characterized by 1H NMR, 13C NMR and HRMS. Their antifungal activities against Gaeumannomyces graminis var. tritici and Fusarium pseudocerealum were evaluated in vitro by the plate method. The results indicated that antifungal activities of compound 2-chloro-N-phenyl-6-(1H-1, 2, 4-triazol-1-yl)benzamide (7i) against Gaeumannomyces graminis var. tritici reached up to 80% at the concentrations of 100 mg/L, and were comparable to the control level of silthiopham at the concentrations of 50 and 25 mg/L. However, these compounds didn't show obvious antifungal activities against Fusarium pseudocerealum.
The synthetic route of substituted 1, 2, 4-triazole benzamide derivatives was explored, which included several steps such as catalytic cross-coupling of 2, 6-dichlorobenzonitrile with a triazole, amidation of nitrile, diazotization of amide and hydrolysis, and amidation of acid. Unreported 14 new 1, 2, 4-triazole benzamide derivatives were synthesized. Their chemical structures were characterized by 1H NMR, 13C NMR and HRMS. Their antifungal activities against Gaeumannomyces graminis var. tritici and Fusarium pseudocerealum were evaluated in vitro by the plate method. The results indicated that antifungal activities of compound 2-chloro-N-phenyl-6-(1H-1, 2, 4-triazol-1-yl)benzamide (7i) against Gaeumannomyces graminis var. tritici reached up to 80% at the concentrations of 100 mg/L, and were comparable to the control level of silthiopham at the concentrations of 50 and 25 mg/L. However, these compounds didn't show obvious antifungal activities against Fusarium pseudocerealum.
2020, 40(8): 2531-2534
doi: 10.6023/cjoc202004006
Abstract:
Two serratane triterpenoids, 3β, 14α, 15α, 21β-tetrahydroxyserrat-15-(3'-methoxyl-4'-hydroxybenzoate) (1) and 16-oxoserrat-14-en-3β, 21α-diol (2), were isolated from the whole plant of Lycopodiella cernua. Compound 1 was a new one. The structures of these compounds were identified by analysis of spectral data. These two compounds were isolated from Lycopodiella genus for the first time.
Two serratane triterpenoids, 3β, 14α, 15α, 21β-tetrahydroxyserrat-15-(3'-methoxyl-4'-hydroxybenzoate) (1) and 16-oxoserrat-14-en-3β, 21α-diol (2), were isolated from the whole plant of Lycopodiella cernua. Compound 1 was a new one. The structures of these compounds were identified by analysis of spectral data. These two compounds were isolated from Lycopodiella genus for the first time.
2020, 40(8): 2583-2584
doi: 10.6023/cjoc202000046
Abstract:
2020, 40(8): 2585-2587
doi: 10.6023/cjoc202000047
Abstract:
2020, 40(8): 2588-2589
doi: 10.6023/cjoc202000048
Abstract:
2020, 40(8): 2590-2591
doi: 10.6023/cjoc202000049
Abstract:
2020, 40(8): 2592-2593
doi: 10.6023/cjoc202000050
Abstract:
2020, 40(8): 2594-2596
doi: 10.6023/cjoc202000051
Abstract:
2020, 40(8): 2597-2599
doi: 10.6023/cjoc202000052
Abstract:
2020, 40(8): 2600-2602
doi: 10.6023/cjoc202000053
Abstract:
2020, 40(8): 2603-2605
doi: 10.6023/cjoc202000054
Abstract:
