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2019 Volume 39 Issue 10
2019, 39(10): 2685-2704
doi: 10.6023/cjoc201903058
Abstract:
As interesting synthetic targets, dimeric cyclotryptamine alkaloids bearing sterically hindered vicinal all-carbon quaternary stereocenters have attracted significant attention from the synthetic community. Stereocontrolled synthesis of the congested all-carbon quaternary stereocenters in these alkaloids presents a formidable challenge. This review summarizes the synthetic efforts towards dimeric cyclotryptamine alkaloids in the last twelve years.
As interesting synthetic targets, dimeric cyclotryptamine alkaloids bearing sterically hindered vicinal all-carbon quaternary stereocenters have attracted significant attention from the synthetic community. Stereocontrolled synthesis of the congested all-carbon quaternary stereocenters in these alkaloids presents a formidable challenge. This review summarizes the synthetic efforts towards dimeric cyclotryptamine alkaloids in the last twelve years.
2019, 39(10): 2705-2712
doi: 10.6023/cjoc201904014
Abstract:
Indolines, an important class of heterocycles with a wide range of biological properties, are a key structural motif in numerous natural products and biologically active compounds. As a result, efficient methods for indolines synthesis have been the subject of extensive studies. In this review, recent studies on the synthesis of various functionalized indolines using unactivated alkenes are described. It involves radical addition/cyclization reaction in the presence of oxidizing agent, which is usually carried out under neutral reaction conditions using readily available oxidizing agents and different transition metals or under metal-free as catalysts.
Indolines, an important class of heterocycles with a wide range of biological properties, are a key structural motif in numerous natural products and biologically active compounds. As a result, efficient methods for indolines synthesis have been the subject of extensive studies. In this review, recent studies on the synthesis of various functionalized indolines using unactivated alkenes are described. It involves radical addition/cyclization reaction in the presence of oxidizing agent, which is usually carried out under neutral reaction conditions using readily available oxidizing agents and different transition metals or under metal-free as catalysts.
2019, 39(10): 2713-2725
doi: 10.6023/cjoc201905036
Abstract:
1, 2, 4-Triazine compounds are an important class of nitrogen-containing heterocyclic compounds. They have wide applications in the fields of medicine, chemicals and materials. Therefore, green and highly efficient synthesis of 1, 2, 4-triazine compounds is increasingly attracting the attention of researchers. By tandem cyclization reaction, the post-treatment of intermediate is avoided, and the one-pot synthesis of triazine compounds is the most efficient and direct synthesis method, which conforms to the concept of green chemistry for its step and atomic economy. The formation of C-N bond based on tandem cyclization to give 1, 2, 4-triazine compounds is reviewed. The synthetic method, reaction mechanism and application of 1, 2, 4-triazine compounds are introduced under transition-metal and metal-free conditions in the past ten years. The prospects of synthesis of triazine rings are also discussed.
1, 2, 4-Triazine compounds are an important class of nitrogen-containing heterocyclic compounds. They have wide applications in the fields of medicine, chemicals and materials. Therefore, green and highly efficient synthesis of 1, 2, 4-triazine compounds is increasingly attracting the attention of researchers. By tandem cyclization reaction, the post-treatment of intermediate is avoided, and the one-pot synthesis of triazine compounds is the most efficient and direct synthesis method, which conforms to the concept of green chemistry for its step and atomic economy. The formation of C-N bond based on tandem cyclization to give 1, 2, 4-triazine compounds is reviewed. The synthetic method, reaction mechanism and application of 1, 2, 4-triazine compounds are introduced under transition-metal and metal-free conditions in the past ten years. The prospects of synthesis of triazine rings are also discussed.
2019, 39(10): 2735-2743
doi: 10.6023/cjoc201904011
Abstract:
Aryl ethers are important central motifs that are abundant in many natural products and drug molecules, as well as versatile building blocks for organic synthesis. Aryl ethers were usually synthesized through the coupling reactions between leaving group substituted arenes and alcohols. However, the introduction of leaving group requires extra synthetic operation and produces lots of wastes. Over the past decade, the method for the synthesis of aryl ethers via C-H alkoxylation or aryloxylation has received much attention due to its potential as an atom and step efficient methodology. Herein, the research advances on the synthesis of aryl ethers through dehydrogenative coupling are reviewed. The detailed substrate scopes and reaction mechanisms, as well as the limitations of current procedures and the prospects for the future, are discussed.
Aryl ethers are important central motifs that are abundant in many natural products and drug molecules, as well as versatile building blocks for organic synthesis. Aryl ethers were usually synthesized through the coupling reactions between leaving group substituted arenes and alcohols. However, the introduction of leaving group requires extra synthetic operation and produces lots of wastes. Over the past decade, the method for the synthesis of aryl ethers via C-H alkoxylation or aryloxylation has received much attention due to its potential as an atom and step efficient methodology. Herein, the research advances on the synthesis of aryl ethers through dehydrogenative coupling are reviewed. The detailed substrate scopes and reaction mechanisms, as well as the limitations of current procedures and the prospects for the future, are discussed.
2019, 39(10): 2744-2758
doi: 10.6023/cjoc201904023
Abstract:
Phenazine-1-carboxylic acid (PCA) as a natural product widely exists in microbial metabolites of Pseudomonads and Streptomycetes, which displays potent inhibitory activities against plant pathogens, and has medical antibacterial and antitumor effects, and so on. In this review, the biosynthesis and chemosynthesis of phenazine-1-carboxylic acid are summarized. At the same time, the diverse biological evaluations of its biosynthetic and chemosynthetic analogues are summarized, which could provide reference for the study of structural modifications and biological activities of these analogues.
Phenazine-1-carboxylic acid (PCA) as a natural product widely exists in microbial metabolites of Pseudomonads and Streptomycetes, which displays potent inhibitory activities against plant pathogens, and has medical antibacterial and antitumor effects, and so on. In this review, the biosynthesis and chemosynthesis of phenazine-1-carboxylic acid are summarized. At the same time, the diverse biological evaluations of its biosynthetic and chemosynthetic analogues are summarized, which could provide reference for the study of structural modifications and biological activities of these analogues.
2019, 39(10): 2759-2770
doi: 10.6023/cjoc201904055
Abstract:
Solanoeclepin A, first isolated from potato roots (Solanaceae Juss.) by Mulder et al., is an highly active hatching stimulant (0.3 g per hectare) of potato cyst nematode (PCN, Globodera rostochiensis and G. pallida) which causes severe damage to potato crops. Its complex chemical structure belongs to a rearranged tetranortriterpene and possesses extremely unique skeleton. Based on the known general biosynthesis of tetranortriterpenoids and Prof. Corey's biomimetic synthesis of glycinoeclepin, a plausible biosynthetic pathway of solanoeclepin A is proposed. A schematic review on the synthetic studies towards solanoeclepin A is provided.
Solanoeclepin A, first isolated from potato roots (Solanaceae Juss.) by Mulder et al., is an highly active hatching stimulant (0.3 g per hectare) of potato cyst nematode (PCN, Globodera rostochiensis and G. pallida) which causes severe damage to potato crops. Its complex chemical structure belongs to a rearranged tetranortriterpene and possesses extremely unique skeleton. Based on the known general biosynthesis of tetranortriterpenoids and Prof. Corey's biomimetic synthesis of glycinoeclepin, a plausible biosynthetic pathway of solanoeclepin A is proposed. A schematic review on the synthetic studies towards solanoeclepin A is provided.
2019, 39(10): 2771-2785
doi: 10.6023/cjoc201904061
Abstract:
Benzo five-/six-membered nitrogen-containing heterocyclic compound with a rigid plane and a large conjugate structure can emit characteristic fluorescence in a variety of organic solvents and mixed solutions, and N, O, S heteroatoms in the structure can serve as binding sites for fluorescent probes. Therefore, in recent years, benzo nitrogen-containing heterocyclic compounds are increasingly becoming one of the research focuses in the field of fluorescent probes. From the perspective of starting materials, synthesis methods, molecular structure, interaction mechanism, benzo five-/ six-membered nitrogen-containing heterocyclic fluorescent probes containing the structure of benzoxazole, benzothiazole, benzimidazole, indole, carbazole, quinoline, benzopyrazine and phenazine are introduced with emphasis. And their detection application for a variety of analytes, such small molecules, metal cations, anions and pH are reviewed. In the future, it is worthy of further attention to the research on the integration of multiple heterocyclic functional structures into a multifunctional fluorescent probe by simple and green synthesis.
Benzo five-/six-membered nitrogen-containing heterocyclic compound with a rigid plane and a large conjugate structure can emit characteristic fluorescence in a variety of organic solvents and mixed solutions, and N, O, S heteroatoms in the structure can serve as binding sites for fluorescent probes. Therefore, in recent years, benzo nitrogen-containing heterocyclic compounds are increasingly becoming one of the research focuses in the field of fluorescent probes. From the perspective of starting materials, synthesis methods, molecular structure, interaction mechanism, benzo five-/ six-membered nitrogen-containing heterocyclic fluorescent probes containing the structure of benzoxazole, benzothiazole, benzimidazole, indole, carbazole, quinoline, benzopyrazine and phenazine are introduced with emphasis. And their detection application for a variety of analytes, such small molecules, metal cations, anions and pH are reviewed. In the future, it is worthy of further attention to the research on the integration of multiple heterocyclic functional structures into a multifunctional fluorescent probe by simple and green synthesis.
2019, 39(10): 2786-2795
doi: 10.6023/cjoc201903060
Abstract:
Human serum albumin (HSA) is the most abundant protein in human blood plasma, which plays important roles in physiological and biological processes, such as keeping the osmotic pressure and transporting small molecular ligands. The level of HSA in in biological samples especially in blood serum can reveal several health conditions, and thus, quantitative determination of HSA has vital importance for disease diagnosis. In recent years, as the rapid development of fluorescent probe technique, a great number of fluorescent probes have been reported for sensitive and selective detection of HSA. This article summarizes recent reported organic-based fluorescent probes, subsequently carefully describes the chemical structures, sensing mechanisms, spectral features, limit of detection, and binding sites, and moreover, the future developments and prospects for HSA detection by using fluorescent probes have been discussed.
Human serum albumin (HSA) is the most abundant protein in human blood plasma, which plays important roles in physiological and biological processes, such as keeping the osmotic pressure and transporting small molecular ligands. The level of HSA in in biological samples especially in blood serum can reveal several health conditions, and thus, quantitative determination of HSA has vital importance for disease diagnosis. In recent years, as the rapid development of fluorescent probe technique, a great number of fluorescent probes have been reported for sensitive and selective detection of HSA. This article summarizes recent reported organic-based fluorescent probes, subsequently carefully describes the chemical structures, sensing mechanisms, spectral features, limit of detection, and binding sites, and moreover, the future developments and prospects for HSA detection by using fluorescent probes have been discussed.
2019, 39(10): 2726-2734
doi: 10.6023/cjoc201903063
Abstract:
Due to the uniqueness of fluorine atom and C-F bond, difluoromethylene has special properties. As a bioisostere of an oxygen or a carbonyl group, it plays an important role in medicines, pesticides and materials. Difluoromethyl heteroaryl sulfones, represented by 2-PySO2CF2H (Hu reagent), have been developed recently as difluoromethylation reagents, and widely recognized by synthetic chemists for their ease of preparation, good functional group tolerance and universal applicability to a wide range of carbonyl compounds. Through different types of reactions such as nucleophilic substitution, nucleophilic addition, Julia-Kocienski olefination reaction, and radical-mediated difunctionalization, they introduced difluoromethyl, difluoromethylene, gem-difluoroalkene and other fluorine-containing groups into aldehydes, ketones, and heterocyclic compounds. For the first time, the synthesis of fluorine-containing organic compounds involved in various difluoromethyl heteroaryl sulfones in the past decade is reviewed from the perspective of reaction types and their application studies.
Due to the uniqueness of fluorine atom and C-F bond, difluoromethylene has special properties. As a bioisostere of an oxygen or a carbonyl group, it plays an important role in medicines, pesticides and materials. Difluoromethyl heteroaryl sulfones, represented by 2-PySO2CF2H (Hu reagent), have been developed recently as difluoromethylation reagents, and widely recognized by synthetic chemists for their ease of preparation, good functional group tolerance and universal applicability to a wide range of carbonyl compounds. Through different types of reactions such as nucleophilic substitution, nucleophilic addition, Julia-Kocienski olefination reaction, and radical-mediated difunctionalization, they introduced difluoromethyl, difluoromethylene, gem-difluoroalkene and other fluorine-containing groups into aldehydes, ketones, and heterocyclic compounds. For the first time, the synthesis of fluorine-containing organic compounds involved in various difluoromethyl heteroaryl sulfones in the past decade is reviewed from the perspective of reaction types and their application studies.
2019, 39(10): 2796-2801
doi: 10.6023/cjoc201907038
Abstract:
A mild and regioselective bromination of phenols with the cheap and easily-available HBr is developed. By replacing the common used dimethyl sulfoxide (DMSO) with sulfoxides bearing sterically hindered substituents, the desired brominated phenols could be obtained in moderate to high yields with up to 99/1 regioselectivity. This method could be easily scaled up to 50 mmol scale and has the potential to isolate the desired product by simple extraction and recrystallization, showing great practicality of this new method.
A mild and regioselective bromination of phenols with the cheap and easily-available HBr is developed. By replacing the common used dimethyl sulfoxide (DMSO) with sulfoxides bearing sterically hindered substituents, the desired brominated phenols could be obtained in moderate to high yields with up to 99/1 regioselectivity. This method could be easily scaled up to 50 mmol scale and has the potential to isolate the desired product by simple extraction and recrystallization, showing great practicality of this new method.
2019, 39(10): 2802-2807
doi: 10.6023/cjoc201904057
Abstract:
An relative eco-friendly protocol for the direct C-3 selenation of imidazo[1, 2-a]pyridines with vorious organoselenides has been developed, gaving the desired products in moderate to excellent yields. Preliminary experimental results are consistent with a C-3 electrophilic functionalization mechanism. The features with relative green reaction conditions, broad substrate scope, and easy scale-up operation would make this strategy promising and important for the preparation of nitrogen and selenium containing molecules.
An relative eco-friendly protocol for the direct C-3 selenation of imidazo[1, 2-a]pyridines with vorious organoselenides has been developed, gaving the desired products in moderate to excellent yields. Preliminary experimental results are consistent with a C-3 electrophilic functionalization mechanism. The features with relative green reaction conditions, broad substrate scope, and easy scale-up operation would make this strategy promising and important for the preparation of nitrogen and selenium containing molecules.
2019, 39(10): 2808-2812
doi: 10.6023/cjoc201904033
Abstract:
An iodine-dimethyl sulfoxide (I2-DMSO) promoted efficient method is described for the synthesis of thiazolo-[3', 2':2, 3]pyrido[4, 5-d]pyrido[1, 2-a]pyrimidin-5-ones (5) via Pictet-Spengler cyclization. The key intermediate, 2-(3-amino-5-phenylaminothiazolo-2-yl)-4H-pyrido[1, 2-a]pyrimidin-4-one (3), was readily prepared from 2-chloromethyl-4H-pyrido-[1, 2-a]pyrimidin-4-one (1) and potassium N-phenyl-N'-cyano-imido-thiocarbonate (2) by Thorpe-Ziegler isomerization. The novel synthetic method offers the advantage of mild reaction conditions, operational simplicity and higher yields.
An iodine-dimethyl sulfoxide (I2-DMSO) promoted efficient method is described for the synthesis of thiazolo-[3', 2':2, 3]pyrido[4, 5-d]pyrido[1, 2-a]pyrimidin-5-ones (5) via Pictet-Spengler cyclization. The key intermediate, 2-(3-amino-5-phenylaminothiazolo-2-yl)-4H-pyrido[1, 2-a]pyrimidin-4-one (3), was readily prepared from 2-chloromethyl-4H-pyrido-[1, 2-a]pyrimidin-4-one (1) and potassium N-phenyl-N'-cyano-imido-thiocarbonate (2) by Thorpe-Ziegler isomerization. The novel synthetic method offers the advantage of mild reaction conditions, operational simplicity and higher yields.
2019, 39(10): 2821-2828
doi: 10.6023/cjoc201904058
Abstract:
A facile and efficient method for the synthesis of 6H-phenanthridines has been successfully developed involving a copper(0)/Selectfluor system-catalyzed tandem annulation/aromatization of o-aryl benzenesulfonylimides. A variety of substituted 6H-phenanthridines were synthesized in moderate to good yields under mild reaction conditions. Mechanistic experiments revealed that the reaction might involve an oxycupration of C=N bond followed by an intramolecular C-H bond amination as the key steps triggered by an in situ generated copper species XCuOH (X=F or BF4) from the Cu(0)/Selectfluor system.
A facile and efficient method for the synthesis of 6H-phenanthridines has been successfully developed involving a copper(0)/Selectfluor system-catalyzed tandem annulation/aromatization of o-aryl benzenesulfonylimides. A variety of substituted 6H-phenanthridines were synthesized in moderate to good yields under mild reaction conditions. Mechanistic experiments revealed that the reaction might involve an oxycupration of C=N bond followed by an intramolecular C-H bond amination as the key steps triggered by an in situ generated copper species XCuOH (X=F or BF4) from the Cu(0)/Selectfluor system.
2019, 39(10): 2829-2834
doi: 10.6023/cjoc201903053
Abstract:
A novel fluorescent sensor based on 5-(3-nitrophenyl)-furan-2-carbaldehyde functionalized barbituric acid derivative (QS) was successfully synthesized. QS was characterized by 1H NMR, 13C NMR and MS. The maximum fluorescence emission wavelength of QS in dimethyl sulfoxide (DMSO) solution was determined to be 498 nm and green fluorescence was emitted under 365 nm ultraviolet lamp. QS showed different fluorescence identification ability for aqueous solution of Hg2+ and Fe3+. Hg2+ can enhance the fluorescence of probe QS to orange, and Fe3+ quenches its fluorescence, thus realizing real-time detection. The limits of detection of QS for Hg2+ and Fe3+ are 3.25×10-8 and 4.0×10-8 mol· L-1, respectively. The fluorescence measurements and MS studies suggest that the binding stoichiometry ratios of QS with Hg2+ and Fe3+ are recognized as 1:1, respectively. The possible modes of QS with Hg2+ and Fe3+ are proposed. The addition of H2PO4- caused the fluorescence of QS-Fe recover, indicating that QS can be used for cyclic detection of Fe3+. More importantly, the separation percentages of the solid QS for Hg2+and Fe3+ are 92.0% and 91.8% in aqueous solution, respectively, indicating that it has excellent ingestion capacity.
A novel fluorescent sensor based on 5-(3-nitrophenyl)-furan-2-carbaldehyde functionalized barbituric acid derivative (QS) was successfully synthesized. QS was characterized by 1H NMR, 13C NMR and MS. The maximum fluorescence emission wavelength of QS in dimethyl sulfoxide (DMSO) solution was determined to be 498 nm and green fluorescence was emitted under 365 nm ultraviolet lamp. QS showed different fluorescence identification ability for aqueous solution of Hg2+ and Fe3+. Hg2+ can enhance the fluorescence of probe QS to orange, and Fe3+ quenches its fluorescence, thus realizing real-time detection. The limits of detection of QS for Hg2+ and Fe3+ are 3.25×10-8 and 4.0×10-8 mol· L-1, respectively. The fluorescence measurements and MS studies suggest that the binding stoichiometry ratios of QS with Hg2+ and Fe3+ are recognized as 1:1, respectively. The possible modes of QS with Hg2+ and Fe3+ are proposed. The addition of H2PO4- caused the fluorescence of QS-Fe recover, indicating that QS can be used for cyclic detection of Fe3+. More importantly, the separation percentages of the solid QS for Hg2+and Fe3+ are 92.0% and 91.8% in aqueous solution, respectively, indicating that it has excellent ingestion capacity.
2019, 39(10): 2835-2842
doi: 10.6023/cjoc201904020
Abstract:
Novel reactive probes (C1 and C2) towards homocysteine/cysteine (Hcy/Cys) were designed and synthesized, based on the unique nucleophilic nature of bio-thiols. In the presence of Hcy/Cys, probe C1 displayed remarkable fluorescence enhancement. Meanwhile, ratiometric fluorescent probe C2 was designed through subtle structure adjustment. Differently, compound C2 displayed dramatic blue-shift in both fluorescence (100 nm) and absorption (95 nm) spectra upon the addition of Hcy/Cys. By virtue of the specific nucleophilic reaction, probe C2 had outstanding selectivity towards Hcy over Cys, GSH and other amino acids. The detection limit of probe C2 was calculated to be as low as 2.8×10-7 mol/L. Moreover, C2 was successfully applied to microscopic imaging for the detection of Hcy in HeLa cells with ratiometric fluorescent methods.
Novel reactive probes (C1 and C2) towards homocysteine/cysteine (Hcy/Cys) were designed and synthesized, based on the unique nucleophilic nature of bio-thiols. In the presence of Hcy/Cys, probe C1 displayed remarkable fluorescence enhancement. Meanwhile, ratiometric fluorescent probe C2 was designed through subtle structure adjustment. Differently, compound C2 displayed dramatic blue-shift in both fluorescence (100 nm) and absorption (95 nm) spectra upon the addition of Hcy/Cys. By virtue of the specific nucleophilic reaction, probe C2 had outstanding selectivity towards Hcy over Cys, GSH and other amino acids. The detection limit of probe C2 was calculated to be as low as 2.8×10-7 mol/L. Moreover, C2 was successfully applied to microscopic imaging for the detection of Hcy in HeLa cells with ratiometric fluorescent methods.
2019, 39(10): 2843-2850
doi: 10.6023/cjoc201902030
Abstract:
Taking advantage of biocompatible β-cyclodextrin (β-CD) and ionic liquid (IL), β-cyclodextrin functionalized with acid ionic liquid (β-CD-AIL) was prepared and characterized by FT-IR, 1H NMR and 13C NMR. β-CD-AIL was evaluated as catalyst for the preparation of 12-aryl-8, 9, 10, 12-tetrahydrobenzo[a]xanthen-11-ones via one-pot condensation reaction of β-naphthol, aromatic aldehydes and cyclic 1, 3-dicarbonyl compounds. The results showed that β-CD-AIL behaved excellent efficiency and recyclability. The key benefits of this protocol involve mild reaction conditions, fast reaction speed, good to excellent yields and simple operational procedure.
Taking advantage of biocompatible β-cyclodextrin (β-CD) and ionic liquid (IL), β-cyclodextrin functionalized with acid ionic liquid (β-CD-AIL) was prepared and characterized by FT-IR, 1H NMR and 13C NMR. β-CD-AIL was evaluated as catalyst for the preparation of 12-aryl-8, 9, 10, 12-tetrahydrobenzo[a]xanthen-11-ones via one-pot condensation reaction of β-naphthol, aromatic aldehydes and cyclic 1, 3-dicarbonyl compounds. The results showed that β-CD-AIL behaved excellent efficiency and recyclability. The key benefits of this protocol involve mild reaction conditions, fast reaction speed, good to excellent yields and simple operational procedure.
2019, 39(10): 2920-2929
doi: 10.6023/cjoc201903073
Abstract:
An efficient cascade oxidation/halogenoaminocyclization reaction of homoallylhydrazides with N-halogensuc-cinimide was developed without addition of other additives under mild reaction conditions to provide pyrazolines. Under the optimized conditions, a variety of highly substituted pyrazoline derivatives were obtained.
An efficient cascade oxidation/halogenoaminocyclization reaction of homoallylhydrazides with N-halogensuc-cinimide was developed without addition of other additives under mild reaction conditions to provide pyrazolines. Under the optimized conditions, a variety of highly substituted pyrazoline derivatives were obtained.
2019, 39(10): 2813-2820
doi: 10.6023/cjoc201903048
Abstract:
A series of novel 1, 4-pentadien-3-one derivatives containing thioether triazole units were synthesized by introducing triazoles bearing thiol groups into the structures of 1, 4-pentadien-3-one. The structures of the newly synthesized compounds were assigned via 1H NMR, 13C NMR and HRMS. Bioassays indicated that some of the compounds showed potential antibacterial activities against X. citri, X. oryzae and R. solanacearum. Among them, compounds F4, F6 and F16 demonstrated appreciable inhibitory effect against Xanthomonas axonopodis pv. citri, with half-maximal effective concentration (EC50) values of 16.3, 9.9 and 15.9 μg/mL, which were better than commercial agent bismerthiazol (54.9 μg/mL). Compounds F1, F7 and F15 demonstrated appreciable inhibitory effects against Xanthomonas oryzae pv. Oryzae with EC50 values of 9.6, 19.2 and 21.3 μg/mL, which were better than commercial agent bismerthiazol (69.3 μg/mL). Compounds F3 and F6also demonstrated appreciable inhibitory effects against Ralstonia solanacearum with EC50 values of 14.2 and 14.5 μg/mL, which were better than commercial agent bismerthiazol (82.6 μg/mL). The possible mechanism of the antibacterial activity of the target compound F6 against Xanthomonas axonopodis was investigated through scanning electron microscopy.
A series of novel 1, 4-pentadien-3-one derivatives containing thioether triazole units were synthesized by introducing triazoles bearing thiol groups into the structures of 1, 4-pentadien-3-one. The structures of the newly synthesized compounds were assigned via 1H NMR, 13C NMR and HRMS. Bioassays indicated that some of the compounds showed potential antibacterial activities against X. citri, X. oryzae and R. solanacearum. Among them, compounds F4, F6 and F16 demonstrated appreciable inhibitory effect against Xanthomonas axonopodis pv. citri, with half-maximal effective concentration (EC50) values of 16.3, 9.9 and 15.9 μg/mL, which were better than commercial agent bismerthiazol (54.9 μg/mL). Compounds F1, F7 and F15 demonstrated appreciable inhibitory effects against Xanthomonas oryzae pv. Oryzae with EC50 values of 9.6, 19.2 and 21.3 μg/mL, which were better than commercial agent bismerthiazol (69.3 μg/mL). Compounds F3 and F6also demonstrated appreciable inhibitory effects against Ralstonia solanacearum with EC50 values of 14.2 and 14.5 μg/mL, which were better than commercial agent bismerthiazol (82.6 μg/mL). The possible mechanism of the antibacterial activity of the target compound F6 against Xanthomonas axonopodis was investigated through scanning electron microscopy.
2019, 39(10): 2851-2859
doi: 10.6023/cjoc201904049
Abstract:
According to the principle of "splicing-up" bioactive substructures, a new series of target compounds were designed and synthesized by incorporating a diphenyl ether moiety into 4-phenylanilines. Moreover, the structures of the synthesized compounds were confirmed by 1H NMR, 13C NMR, HRMS and melting points measurements. The inhibitory activities of these compounds were evaluated against succinate-cytochrome reductase (SCR). Based on the bioassay results, target compound N-(4-(2-chloro-4-(trifluoromethyl)phenoxy)-3-fluorophenyl)-[1, 1'-biphenyl]-4-amine (3o) exhibited an inhibition rate of 46.44% at a concentration of 10 μmol·L-1, which demonstrated potential values for further investigations.
According to the principle of "splicing-up" bioactive substructures, a new series of target compounds were designed and synthesized by incorporating a diphenyl ether moiety into 4-phenylanilines. Moreover, the structures of the synthesized compounds were confirmed by 1H NMR, 13C NMR, HRMS and melting points measurements. The inhibitory activities of these compounds were evaluated against succinate-cytochrome reductase (SCR). Based on the bioassay results, target compound N-(4-(2-chloro-4-(trifluoromethyl)phenoxy)-3-fluorophenyl)-[1, 1'-biphenyl]-4-amine (3o) exhibited an inhibition rate of 46.44% at a concentration of 10 μmol·L-1, which demonstrated potential values for further investigations.
2019, 39(10): 2860-2866
doi: 10.6023/cjoc201902024
Abstract:
N-Salicylaldehyde hydrazone modified 11-azaartemisinins and their deoxy analogues were designed and synthesized. By using various techniques including UV-vis, fluorescence, NMR as well as molecular modeling, the conformations of (3R, 5aS, 6R, 8aS, 9R, 12S, 12aR)-11-(((E)-2-hydroxy-5-(4-hydroxy-3-((E)-(((3R, 5aS, 6R, 8aS, 9R, 12R, 12aR)-3, 6, 9-trimethyl-10-oxodecahydro-3, 12-epoxy[1, 2]dioxepino[4, 3-i]isoquinolin-11(12H)-yl)imino)methyl)benzyl)benzylidene)amino)-3, 6, 9-trimethyldecahydro-3, 12-epoxy[1, 2]dioxepino[4, 3-i]isoquinolin-10(3H)-one (3) was analyzed, the binding behavior between 3 and hemin was measured, and the solubility-enhancing property of 3 by calix[4]carbazole was evaluated. The results show that the intramolecular hydrogen binding between the N atom of Schiff base in N-salicylaldehyde hydrazone bond and the OH favors the formation of tweezer-like conformation of 3, which enables it to interact with hemin in 1:1 ratio. Moreover, the poor solubility of 3 in water could be enhanced due to its interaction with calix[4]carbazole, which pave the way for the further evaluation of the bioactivities of 3 in the future.
N-Salicylaldehyde hydrazone modified 11-azaartemisinins and their deoxy analogues were designed and synthesized. By using various techniques including UV-vis, fluorescence, NMR as well as molecular modeling, the conformations of (3R, 5aS, 6R, 8aS, 9R, 12S, 12aR)-11-(((E)-2-hydroxy-5-(4-hydroxy-3-((E)-(((3R, 5aS, 6R, 8aS, 9R, 12R, 12aR)-3, 6, 9-trimethyl-10-oxodecahydro-3, 12-epoxy[1, 2]dioxepino[4, 3-i]isoquinolin-11(12H)-yl)imino)methyl)benzyl)benzylidene)amino)-3, 6, 9-trimethyldecahydro-3, 12-epoxy[1, 2]dioxepino[4, 3-i]isoquinolin-10(3H)-one (3) was analyzed, the binding behavior between 3 and hemin was measured, and the solubility-enhancing property of 3 by calix[4]carbazole was evaluated. The results show that the intramolecular hydrogen binding between the N atom of Schiff base in N-salicylaldehyde hydrazone bond and the OH favors the formation of tweezer-like conformation of 3, which enables it to interact with hemin in 1:1 ratio. Moreover, the poor solubility of 3 in water could be enhanced due to its interaction with calix[4]carbazole, which pave the way for the further evaluation of the bioactivities of 3 in the future.
2019, 39(10): 2867-2874
doi: 10.6023/cjoc201904042
Abstract:
A tetrapyridyl substituted corannulene derivative COPY2 was designed and synthesized. Only in the presence of template molecule C60 or C70, COPY2 and palladium could form 1:1 molecular cage complex C60/70⊂COPY2-Pd by self-assembly at room temperature and 55℃ respectively. C60 and C70 were used not only as a template for constructing target molecular cages, but also as a stabilizer for molecular cage. When 1.0 equiv. C70 mixed with C60⊂COPY2-Pd or 1.0 equiv. C60 mixed with C70⊂COPY2-Pd, the ratio of complex C60⊂COPY2-Pd to C70⊂COPY2-Pd is 4:1 after the mixtures were heated at 90℃ for 48 h, which is consistent with the ratio of COPY2 and Pd(CH3CN)2Cl2 mixed with C60 and C70 (1:1). Only the complex C60⊂COPY2-Pd was observed when the ratio of C60 to C70 is 2:1. However, even the ratio of C60 to C70 is 1:2, complex C60⊂COPY2-Pd is still the dominant species in the mixture. These results demonstrate that complexing ability of COPY2 with C60 is stronger than that of COPY2 with C70. 4-Dimethylaminopyridine (DMAP) was chosen to dissociate the cage so as to release fullerene and ligand. Therefore, the ligand COPY2 could be used to the enrichment of C60 at room temperature.
A tetrapyridyl substituted corannulene derivative COPY2 was designed and synthesized. Only in the presence of template molecule C60 or C70, COPY2 and palladium could form 1:1 molecular cage complex C60/70⊂COPY2-Pd by self-assembly at room temperature and 55℃ respectively. C60 and C70 were used not only as a template for constructing target molecular cages, but also as a stabilizer for molecular cage. When 1.0 equiv. C70 mixed with C60⊂COPY2-Pd or 1.0 equiv. C60 mixed with C70⊂COPY2-Pd, the ratio of complex C60⊂COPY2-Pd to C70⊂COPY2-Pd is 4:1 after the mixtures were heated at 90℃ for 48 h, which is consistent with the ratio of COPY2 and Pd(CH3CN)2Cl2 mixed with C60 and C70 (1:1). Only the complex C60⊂COPY2-Pd was observed when the ratio of C60 to C70 is 2:1. However, even the ratio of C60 to C70 is 1:2, complex C60⊂COPY2-Pd is still the dominant species in the mixture. These results demonstrate that complexing ability of COPY2 with C60 is stronger than that of COPY2 with C70. 4-Dimethylaminopyridine (DMAP) was chosen to dissociate the cage so as to release fullerene and ligand. Therefore, the ligand COPY2 could be used to the enrichment of C60 at room temperature.
2019, 39(10): 2882-2891
doi: 10.6023/cjoc201903030
Abstract:
A series of carboxyl group or hydroxyl group functionalized organocatalysts were synthesized and applied in three component reaction of carbon dioxide with epoxide, and aryl amines for the synthesis of 3-aryl-2-oxazolidinones. The method allows the reaction to proceed smoothly in the mild reaction conditions, together with excellent substrates scope of epoxides and aryl amines. The control experiments suggest that the cyclic carbonates are formed by the coupling of epoxides with carbon dioxide, which further react with the amino alcohol generated from epoxides and aryl amines, finally resulting in the desired products.
A series of carboxyl group or hydroxyl group functionalized organocatalysts were synthesized and applied in three component reaction of carbon dioxide with epoxide, and aryl amines for the synthesis of 3-aryl-2-oxazolidinones. The method allows the reaction to proceed smoothly in the mild reaction conditions, together with excellent substrates scope of epoxides and aryl amines. The control experiments suggest that the cyclic carbonates are formed by the coupling of epoxides with carbon dioxide, which further react with the amino alcohol generated from epoxides and aryl amines, finally resulting in the desired products.
2019, 39(10): 2898-2905
doi: 10.6023/cjoc201904021
Abstract:
Atom-efficient [2+2+2] cycloaddition reaction of alkynes in green solvent supercritical carbon dioxide (ScCO2) is an environmentally friendly reaction process that conforms to the principles of green chemistry. Cyclotrimerization of terminal alkynes catalyzed by Co2(CO)8 in pure ScCO2 has been studied to obtain 1, 2, 4-trisubstituted benzene derivatives with excellent selectivity. The reaction conditions for the cyclotrimerization were optimized, such as concentration of catalyst, CO2 pressure, reaction temperature and time. The solubility and phase behavior of the reaction materials and catalysts in ScCO2 medium were discussed, and the mechanism of Co2(CO)8 catalyzed cyclotrimerization of terminal alkynes was assumed. The reaction substrate was extended from C≡C (alkyne) to C≡N (nitrile), and the alkyne-nitrile cycloaddition reaction in ScCO2 was preliminary explored. Our optimized catalytic system for the cyclotrimerization of terminal alkynes exhibited wide substrate scope and high product selectivity, in which no organic co-solvent or additives were added. It provided a green synthetic method for 1, 2, 4-trisubstituted benzenes.
Atom-efficient [2+2+2] cycloaddition reaction of alkynes in green solvent supercritical carbon dioxide (ScCO2) is an environmentally friendly reaction process that conforms to the principles of green chemistry. Cyclotrimerization of terminal alkynes catalyzed by Co2(CO)8 in pure ScCO2 has been studied to obtain 1, 2, 4-trisubstituted benzene derivatives with excellent selectivity. The reaction conditions for the cyclotrimerization were optimized, such as concentration of catalyst, CO2 pressure, reaction temperature and time. The solubility and phase behavior of the reaction materials and catalysts in ScCO2 medium were discussed, and the mechanism of Co2(CO)8 catalyzed cyclotrimerization of terminal alkynes was assumed. The reaction substrate was extended from C≡C (alkyne) to C≡N (nitrile), and the alkyne-nitrile cycloaddition reaction in ScCO2 was preliminary explored. Our optimized catalytic system for the cyclotrimerization of terminal alkynes exhibited wide substrate scope and high product selectivity, in which no organic co-solvent or additives were added. It provided a green synthetic method for 1, 2, 4-trisubstituted benzenes.
2019, 39(10): 2912-2919
doi: 10.6023/cjoc201902026
Abstract:
In order to improve the application of chiral phosphoramide ligands in catalytic asymmetric reactions, thiophosphoramide, which was synthesized from trans-1, 2-cyclohexanediamine was used as a catalyst to synthesize chiral diarylmethanol compounds through addition reaction. The catalytic activity of the ligand in the asymmetric addition reaction of the arylalkyl zincs to the aromatic aldehyde can be as high as 94% ee under the optimized reaction conditions in the presence of 30 mol% phosphoramide ligand N-((1R, 2R)-2-(isopropylamino)cyclohexyl)-P, P-diphenylphosphinic amide (9c) and the corresponding chiral diarylmethanol compound was obtained with the yields of >90%. Despite the large amount of catalyst, the ligand is very convenient to recycle and reuse in this system. At the same time, the reaction mechanism was speculated, and it is believed that the quaternary transition state and the six-element transition state formed by the reaction process are beneficial to improve the enantioselectivity of the reaction.
In order to improve the application of chiral phosphoramide ligands in catalytic asymmetric reactions, thiophosphoramide, which was synthesized from trans-1, 2-cyclohexanediamine was used as a catalyst to synthesize chiral diarylmethanol compounds through addition reaction. The catalytic activity of the ligand in the asymmetric addition reaction of the arylalkyl zincs to the aromatic aldehyde can be as high as 94% ee under the optimized reaction conditions in the presence of 30 mol% phosphoramide ligand N-((1R, 2R)-2-(isopropylamino)cyclohexyl)-P, P-diphenylphosphinic amide (9c) and the corresponding chiral diarylmethanol compound was obtained with the yields of >90%. Despite the large amount of catalyst, the ligand is very convenient to recycle and reuse in this system. At the same time, the reaction mechanism was speculated, and it is believed that the quaternary transition state and the six-element transition state formed by the reaction process are beneficial to improve the enantioselectivity of the reaction.
2019, 39(10): 2930-2935
doi: 10.6023/cjoc201904006
Abstract:
Triarylphosphines play an important role in pharmaceutical synthesis and transition-meal-catalyzed reactions. In this paper, a novel method for the synthesis of triarylphosphines via base-promoted C(sp2)-P cross-coupling reactions of alkyldiphenylphosphines with aryl halides is described. The transition-metal-free reaction condition, readily available starting materials and experimental simplicity are the features of the novel method.
Triarylphosphines play an important role in pharmaceutical synthesis and transition-meal-catalyzed reactions. In this paper, a novel method for the synthesis of triarylphosphines via base-promoted C(sp2)-P cross-coupling reactions of alkyldiphenylphosphines with aryl halides is described. The transition-metal-free reaction condition, readily available starting materials and experimental simplicity are the features of the novel method.
2019, 39(10): 2875-2881
doi: 10.6023/cjoc201903062
Abstract:
In order to find new anti-tumor drugs with targeted therapeutic effect, a series of novel 4-aminoquinazoline derivatives bearing urea moiety were designed, synthesized and evaluated for antitumor activity against four human cancer cell lines of MCF-7, MGC-803, SW620 and A549 using methyl thiazolyl tetrazolium (MTT) assay. Most of the target compounds exhibited excellent anti-tumor activity against the four human tumor cell lines. Among them, 2-((4-((3, 4, 5-trimethoxyphenyl)-amino)quinazolin-2-yl)-thio)-N-((3, 4, 5-trimethoxyphenyl)carbamoyl)acetamide (10p) showed the best antitumor activity against MGC-803, SW620 and A549 cancer cell lines with IC50 values of (7.02±0.46), (6.00±0.78) and (7.04±1.11) μmol· L-1, respectively. Its activity was comparable to the positive control of gefitinib. Molecular docking showed that compound 10p could bind well with EGFR, suggesting that it could be a potential antitumor agent.
In order to find new anti-tumor drugs with targeted therapeutic effect, a series of novel 4-aminoquinazoline derivatives bearing urea moiety were designed, synthesized and evaluated for antitumor activity against four human cancer cell lines of MCF-7, MGC-803, SW620 and A549 using methyl thiazolyl tetrazolium (MTT) assay. Most of the target compounds exhibited excellent anti-tumor activity against the four human tumor cell lines. Among them, 2-((4-((3, 4, 5-trimethoxyphenyl)-amino)quinazolin-2-yl)-thio)-N-((3, 4, 5-trimethoxyphenyl)carbamoyl)acetamide (10p) showed the best antitumor activity against MGC-803, SW620 and A549 cancer cell lines with IC50 values of (7.02±0.46), (6.00±0.78) and (7.04±1.11) μmol· L-1, respectively. Its activity was comparable to the positive control of gefitinib. Molecular docking showed that compound 10p could bind well with EGFR, suggesting that it could be a potential antitumor agent.
2019, 39(10): 2892-2897
doi: 10.6023/cjoc201903049
Abstract:
A convenient and efficient approach for the synthesis of 5-(1-phenyl-3-phenylprop-2-ynyl)-2, 2-pentylidene-1, 3-dioxane-4, 6-dione derivatives through a three-component reaction of aldehydes with 2, 2-pentylidene-1, 3-dioxane-4, 6-dione and arylacetylene in the presence of Cu(OAc)2·H2O/Cu is described with 12 examples. The reaction tolerates a wide range of aldehydes furnishing the products with good to excellent isolated yields (65%~88%). Additionally, the synthetic protocol has the advantages of wild conditions, simple operation, and excessive copper reused.
A convenient and efficient approach for the synthesis of 5-(1-phenyl-3-phenylprop-2-ynyl)-2, 2-pentylidene-1, 3-dioxane-4, 6-dione derivatives through a three-component reaction of aldehydes with 2, 2-pentylidene-1, 3-dioxane-4, 6-dione and arylacetylene in the presence of Cu(OAc)2·H2O/Cu is described with 12 examples. The reaction tolerates a wide range of aldehydes furnishing the products with good to excellent isolated yields (65%~88%). Additionally, the synthetic protocol has the advantages of wild conditions, simple operation, and excessive copper reused.
2019, 39(10): 2906-2911
doi: 10.6023/cjoc201904036
Abstract:
An ipso-oxidation of allyl ether/decarboxylative aromatization cascade strategy is reported, resulting in the formation of N-alkyl pyrroles via oxocarbenium activation. This transformation, which involves formation of C-N bond and cleavage of C-O bond, provides a novel protocol that furnishes N-alkyl pyrroles in 29%~71% yields with good functional group tolerance.
An ipso-oxidation of allyl ether/decarboxylative aromatization cascade strategy is reported, resulting in the formation of N-alkyl pyrroles via oxocarbenium activation. This transformation, which involves formation of C-N bond and cleavage of C-O bond, provides a novel protocol that furnishes N-alkyl pyrroles in 29%~71% yields with good functional group tolerance.
2019, 39(10): 2936-2940
doi: 10.6023/cjoc201907024
Abstract:
The total synthesis of natural products pulchrol and pulchral with antiprotozoan activity was reported, starting from the cheap hydroquinone and 4-methylbenzoic acid and using palladium-catalyzed intramolecular decarboxylation coupling reaction of arene carboxylic acids with aryl bromides as the key reaction. This method provides an opportunity for further study of the structure-activity relationship.
The total synthesis of natural products pulchrol and pulchral with antiprotozoan activity was reported, starting from the cheap hydroquinone and 4-methylbenzoic acid and using palladium-catalyzed intramolecular decarboxylation coupling reaction of arene carboxylic acids with aryl bromides as the key reaction. This method provides an opportunity for further study of the structure-activity relationship.
2019, 39(10): 2941-2945
doi: 10.6023/cjoc201903075
Abstract:
Three cis-selenophenolato iron hydrides[cis-[(ArSe)FeH(PMe3)4] (Ar=Ph (1), p-MeOC6H4 (2) and o-MeC6H4 (3)], were used as catalysts for the dehydration of primary amides to nitriles. The experimental results show that three complexes have good catalytic effect on reductive dehydration of primary amide to nitrile under mild conditions using (EtO)3SiH as reducing agent. The catalytic system is well tolerated to the substituents on the benzene ring in aromatic amides. Compared with electron-donating group, electron-withdrawing group is more advantageous to the catalytic reaction.
Three cis-selenophenolato iron hydrides[cis-[(ArSe)FeH(PMe3)4] (Ar=Ph (1), p-MeOC6H4 (2) and o-MeC6H4 (3)], were used as catalysts for the dehydration of primary amides to nitriles. The experimental results show that three complexes have good catalytic effect on reductive dehydration of primary amide to nitrile under mild conditions using (EtO)3SiH as reducing agent. The catalytic system is well tolerated to the substituents on the benzene ring in aromatic amides. Compared with electron-donating group, electron-withdrawing group is more advantageous to the catalytic reaction.
2019, 39(10): 2946-2951
doi: 10.6023/cjoc201904050
Abstract:
A convenient protocol for the synthesis of multi-substituted alkenes from (Z)-1, 2-diarylthio-1, 2-diarylalkenes with Grignard reagents was developed via the highly selective coupling of (Z)-1, 2-diarylthio-1, 2-diarylalkenes catalyzed by 5.0 mol% NiCl2(dppe). The leaving organosulfur group could be converted to diaryldisulfide after hydrolysis and oxidation, which realized the recycling of sulfur resources, meeting the requirements of green chemistry. This process tolerated to different (Z)-1, 2-diarylthio-1, 2-diarylalkenes and Grignard reagents to deliver products in good to excellent yields, providing an efficient route to multi-substituted alkenes.
A convenient protocol for the synthesis of multi-substituted alkenes from (Z)-1, 2-diarylthio-1, 2-diarylalkenes with Grignard reagents was developed via the highly selective coupling of (Z)-1, 2-diarylthio-1, 2-diarylalkenes catalyzed by 5.0 mol% NiCl2(dppe). The leaving organosulfur group could be converted to diaryldisulfide after hydrolysis and oxidation, which realized the recycling of sulfur resources, meeting the requirements of green chemistry. This process tolerated to different (Z)-1, 2-diarylthio-1, 2-diarylalkenes and Grignard reagents to deliver products in good to excellent yields, providing an efficient route to multi-substituted alkenes.
2019, 39(10): 2952-2957
doi: 10.6023/cjoc201905019
Abstract:
A novel alternating amphiphilic copolymer poly(tetra glycol-a-N, N-bis[2-(1H-1, 2, 3-triazol-1-yl)ethyl]-4-phenyl-diazenyl-aniline)[P(EG4-a-NAzo)] with azobenzene pendants was synthesized through the azide-alkyne click reaction, in which the hydrophilic unit was tetra glycol (EG4) and N, N-bis[2-(1H-1, 2, 3-triazol-1-yl)ethyl]-4-phenyldiazenyl-aniline (NAzo) performed the hydrophobic unit. P(EG4-a-NAzo) could self-assemble into worm-like aggregate in aqueous solution with initially low concentration. Because of its unique alternating topologies, the azobenzene moiety of P(EG4-a-NAzo) micelle could not pile up orderly. This novel azobenzene copolymer has arisen new thoughts and approaches for the molecular design of photo-functional polymers.
A novel alternating amphiphilic copolymer poly(tetra glycol-a-N, N-bis[2-(1H-1, 2, 3-triazol-1-yl)ethyl]-4-phenyl-diazenyl-aniline)[P(EG4-a-NAzo)] with azobenzene pendants was synthesized through the azide-alkyne click reaction, in which the hydrophilic unit was tetra glycol (EG4) and N, N-bis[2-(1H-1, 2, 3-triazol-1-yl)ethyl]-4-phenyldiazenyl-aniline (NAzo) performed the hydrophobic unit. P(EG4-a-NAzo) could self-assemble into worm-like aggregate in aqueous solution with initially low concentration. Because of its unique alternating topologies, the azobenzene moiety of P(EG4-a-NAzo) micelle could not pile up orderly. This novel azobenzene copolymer has arisen new thoughts and approaches for the molecular design of photo-functional polymers.
2019, 39(10): 2965-2972
doi: 10.6023/cjoc201903031
Abstract:
In order to find new lead compound with higher fungicidal activity, a series of novel cinnamaldehyde thio-semicarbazone derivatives were designed and synthesized according to scaffold hopping strategy, based on the lead of the thiosemicarbazide derivatives containing piperidine discovered in our preliminary studies. Their structures were confirmed by 1H NMR, 13C NMR, IR, elemental analysis or HRMS. The bioassay results indicated that some compounds exhibited excellent fungicidal activities. In particular, N'-((1E, 2E)-3-(4-chlorophenyl)allylidene)piperidine-1-carbothiohydrazide (3a) and N'-((1E, 2E)-3-phenylallylidene)piperidine-1-carbothiohydrazide (3p) showed above 95% inhibitory rate against Cytospora sp, S. sclerotiorum, P. aphanidermatum and T. cucumeris at 50 μg/mL with EC50 values lower than 10 μg/mL. The preliminary structure-activity relationship indicated that cinnamaldehyde contributes more to the bioactivity than benzaldehyde.
In order to find new lead compound with higher fungicidal activity, a series of novel cinnamaldehyde thio-semicarbazone derivatives were designed and synthesized according to scaffold hopping strategy, based on the lead of the thiosemicarbazide derivatives containing piperidine discovered in our preliminary studies. Their structures were confirmed by 1H NMR, 13C NMR, IR, elemental analysis or HRMS. The bioassay results indicated that some compounds exhibited excellent fungicidal activities. In particular, N'-((1E, 2E)-3-(4-chlorophenyl)allylidene)piperidine-1-carbothiohydrazide (3a) and N'-((1E, 2E)-3-phenylallylidene)piperidine-1-carbothiohydrazide (3p) showed above 95% inhibitory rate against Cytospora sp, S. sclerotiorum, P. aphanidermatum and T. cucumeris at 50 μg/mL with EC50 values lower than 10 μg/mL. The preliminary structure-activity relationship indicated that cinnamaldehyde contributes more to the bioactivity than benzaldehyde.
2019, 39(10): 2973-2979
doi: 10.6023/cjoc201904038
Abstract:
Amphiphilic block copolypeptides of polyethylene glycol-b-poly(L-glutamic acid) (PEG-b-PGlu) were synthesized to self-assemble with 4-methyl-4-aza[4]helicene onium ion (Me[4]H) in water through charge-conjugation. The morphology of the assemblies was studied by varying PGlu block length, the molar ratio of Glu unit/Me[4]H and pH value. It was found that when rigid-flexible block copolymers were assembled together with small molecules which had rigid, large size and inductive effect, they would follow a completely different law from the charge-conjugated assembly of flexible macromolecules. The self-assemblies were controlled by the π-π stacking of helicene, together with the volume fraction of the hydrophobic parts and the rigidity of PGlu segments. These effects restricted each other in the assembly process. When π-π stacking was dominant, assembly morphologies with pointer-like and strip-like planar structures were obtained.
Amphiphilic block copolypeptides of polyethylene glycol-b-poly(L-glutamic acid) (PEG-b-PGlu) were synthesized to self-assemble with 4-methyl-4-aza[4]helicene onium ion (Me[4]H) in water through charge-conjugation. The morphology of the assemblies was studied by varying PGlu block length, the molar ratio of Glu unit/Me[4]H and pH value. It was found that when rigid-flexible block copolymers were assembled together with small molecules which had rigid, large size and inductive effect, they would follow a completely different law from the charge-conjugated assembly of flexible macromolecules. The self-assemblies were controlled by the π-π stacking of helicene, together with the volume fraction of the hydrophobic parts and the rigidity of PGlu segments. These effects restricted each other in the assembly process. When π-π stacking was dominant, assembly morphologies with pointer-like and strip-like planar structures were obtained.
2019, 39(10): 2980-2984
doi: 10.6023/cjoc201904001
Abstract:
Mercury ion pollution has serious harmful impact on the ecological environment and human health. It is of great significance to develop a probe with high selectivity and sensitivity that could be applied to the detection of mercury ion in water environment. In this paper, a novel excited-state intramolecular proton transfer (ESIPT) fluorescent probe containing barbitone unit was designed and synthesized from salicylaldehyde. Mechanism studies showed that mercury ions and probes formed a structure similar to "(thymine)T-Hg-T" which has high selectivity in determining mercury ions. The calibration curve indicated that there was a good linear correlation between the relative fluorescent intensities over the concentration range of 4~20 μmol·L-1 of Hg2+ ion.
Mercury ion pollution has serious harmful impact on the ecological environment and human health. It is of great significance to develop a probe with high selectivity and sensitivity that could be applied to the detection of mercury ion in water environment. In this paper, a novel excited-state intramolecular proton transfer (ESIPT) fluorescent probe containing barbitone unit was designed and synthesized from salicylaldehyde. Mechanism studies showed that mercury ions and probes formed a structure similar to "(thymine)T-Hg-T" which has high selectivity in determining mercury ions. The calibration curve indicated that there was a good linear correlation between the relative fluorescent intensities over the concentration range of 4~20 μmol·L-1 of Hg2+ ion.
2019, 39(10): 2958-2964
doi: 10.6023/cjoc201903020
Abstract:
Oxaprozin is a common anti-inflammatory drug in the clinic. Oral medication of oxaprozin potentially induces the GI perforation, which is caused by the local irritation of its carboxylic acid group. Paeonol is an active ingredient of peony, and has anti-inflammatory and anti-oxidant effects. So oxaprozin-paeonol ester (OPE) was designed to avoid the GI complications and enhence corresponding anti-inflammatory. The topical anti-inflammatory effects of OPE was evaluated in a 12-O-tetradecanoylphorbol-13-acetate (TPA) induced mouse ear edema model. The results showed that topical treatment of OPE could effectively improve the TPA-induced ear edema and its anti-inflammatory effect is 2 times higher than that of oxaprozin and 4 times than that of paeonol. Moreover, OPE treatment could effectively mitigate the expression of IL-1β, IL-6, and TNF-α, and its effect is better than that of oxaprozin or paeonol. Furthor study demonstrated that topical treatment of OPE could obviously down-regulate the activation of factor kappa-κB (NF-κB) by blocking IκB kinase (IKK) activities. Accordingly, OPE might be used as a promising anti-inflammatory agent for inflammation-associated skin diseases.
Oxaprozin is a common anti-inflammatory drug in the clinic. Oral medication of oxaprozin potentially induces the GI perforation, which is caused by the local irritation of its carboxylic acid group. Paeonol is an active ingredient of peony, and has anti-inflammatory and anti-oxidant effects. So oxaprozin-paeonol ester (OPE) was designed to avoid the GI complications and enhence corresponding anti-inflammatory. The topical anti-inflammatory effects of OPE was evaluated in a 12-O-tetradecanoylphorbol-13-acetate (TPA) induced mouse ear edema model. The results showed that topical treatment of OPE could effectively improve the TPA-induced ear edema and its anti-inflammatory effect is 2 times higher than that of oxaprozin and 4 times than that of paeonol. Moreover, OPE treatment could effectively mitigate the expression of IL-1β, IL-6, and TNF-α, and its effect is better than that of oxaprozin or paeonol. Furthor study demonstrated that topical treatment of OPE could obviously down-regulate the activation of factor kappa-κB (NF-κB) by blocking IκB kinase (IKK) activities. Accordingly, OPE might be used as a promising anti-inflammatory agent for inflammation-associated skin diseases.
