A previous study was conducted on the synthesis and antibacterial evaluation of Mannich bases of 2-(thioalkyl)-1H-methylbenzimidazole derivatives. The results of this study showed that certain 2-(thioalkyl)-1H-methylb...A previous study was conducted on the synthesis and antibacterial evaluation of Mannich bases of 2-(thioalkyl)-1H-methylbenzimidazole derivatives. The results of this study showed that certain 2-(thioalkyl)-1H-methylbenzimidazole and 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl)benzimidazole derivatives possess antibacterial activities against clinical strains, such as Escherichia coli, Klebsiella pneumonia (Gram-negative bacteria), Staphylococcus aureus and Pseudomonas aeruginosa (Gram-positive bacteria). Following these favorable results, we extended the antibacterial evaluation of this series of molecules to environmental strains. The aim of this study was to assess the impact of the methyl-piperidine group fixed at position-1 of this new series of benzimidazoles on the antibacterial activity of environmental strains. In addition, we first evaluated the antibacterial activity of four 2-(thioalkyl)methylbenzimidazole derivatives and then that of five 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives. This study allowed us to show that compounds 1d and 1e could inhibit bacterial growth in vitro of the Enterobacteria P1 strain with inhibition diameters of 17.3 ± 0.6 mm and 10 ± 0.0 mm, respectively. However, addition of methyl-piperidinyl in this series showed that five (5) of 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives had an inhibitory effect on the in vitro growth of bacterial strains used except on Enterobacteria P2 with inhibition diameters between 10.0 ± 0.8 mm and 27.9 ± 1.4 mm. The introduction of the methyl-piperidinyl group at the 1-position of 2-(thioalkyl)-1H-methylbenzimidazole derivatives greatly improved the antibacterial activity against environmental bacteria such as Escherichia coli A1, A2, A3, and A4 and two Enterobacteria P1.展开更多
Five new C-8 Mannich base derivatives of irisolidone 2a-2e were synthesized and their nitric oxide（NO）production inhibitory activity was evaluated.Compounds 2a,2b,2c and 2e displayed stronger activities in vitro tha...Five new C-8 Mannich base derivatives of irisolidone 2a-2e were synthesized and their nitric oxide（NO）production inhibitory activity was evaluated.Compounds 2a,2b,2c and 2e displayed stronger activities in vitro than the parent compound irisolidone.展开更多
This paper describes a combinatorial Synthesis of the Mannich Bases in Solution through the Mannich reaction using 3 ketones, 5 amines and formaldehyde in solution and hydrochloride as a catalyst and then using a macr...This paper describes a combinatorial Synthesis of the Mannich Bases in Solution through the Mannich reaction using 3 ketones, 5 amines and formaldehyde in solution and hydrochloride as a catalyst and then using a macroporous quarterized ammonium resin (CO32- form) as a scavenge agent to remove the acid catalyst when the Mannich reaction is completed. It was found by GC/MS analysis that the symmetrical ketone, such as acetone, in the Mannich reaction mainly produces one Mannich base; while the asymmetrical ketone, such as 2-pentanone, gives two Mannich bases. The reactivity depends on the tereo-hinder of both ketones and amines.展开更多
Two new Mannich and Schiff base ligands namely： （1-（3＇-amino-methyl-1＇（H）-1＇,2＇,4＇-triazole）-3-（1＇（H）-l＇,2＇,4＇- triazole-3＇-yl） iminoisatin （Lt） and l-morpholinomethyl-3-（1＇（H）-1＇,2＇,4＇-tr...Two new Mannich and Schiff base ligands namely： （1-（3＇-amino-methyl-1＇（H）-1＇,2＇,4＇-triazole）-3-（1＇（H）-l＇,2＇,4＇- triazole-3＇-yl） iminoisatin （Lt） and l-morpholinomethyl-3-（1＇（H）-1＇,2＇,4＇-triazolyl）iminoisatin （LII） were prepared from condensation reaction of the new Schiff base 3-（l＇（H）-l＇,2＇,4＇-triazole-3＇-yl）iminoisatin （SBH） （0.01 mol） with formaldehyde and 3-amino-l,2,4-triazole （3-At） or with formaldehyde and morpholine （0.01 mole each） respectively. Structures were characterized by tH NMR, CHN analyses, mass spectra and IR spectra. Metal complexes were synthesized by heating each ligand （0.02 mo with metal salts （0.01 moo in ethanol or ethanol： acetone mixture respectively. The formula of metal complexes were suggested depending on CHN and thermal analyses, metal and chloride contents, IR and UV-visible spectra, magnetic moments （laefr） and conductivity measurements. All complexes were of octahedral geometry except palladium （II） complexes which were square planar. The two ligands and some selected metal complexes showed various antibacterial and cytotoxic effects.展开更多
A series of novel furan/thiophene and piperazine-containing 1,2,4-triazole Mannich bases and bis（1,2,4-triazole） Mannich bases have been conveniently synthesized via Mannich reaction with triazole Schiff bases, vari...A series of novel furan/thiophene and piperazine-containing 1,2,4-triazole Mannich bases and bis（1,2,4-triazole） Mannich bases have been conveniently synthesized via Mannich reaction with triazole Schiff bases, various pipera- zinc derivatives, and formaldehyde as intermediates in good yields. Their structures were characterized by melting points, ~H NMR, 13C NMR, IR and elemental analysis. The preliminary bioassay showed that most compounds ex- hibited significant in vitro and in vivo fungicidal activity against several test plant fungi. Among 32 new compounds, the trifluoromethyl-containing compounds showed superior activity than the methyl-containing ones. Several com- pounds, such as FS, F9, F10, G5, HT, 118, 13 and 14, were comparable with some commercial fungicides against different fungi during the present study and could be further structurally optimized. Meanwhile, several compounds showed good herbicidal activity against Brassica campestris at 100 ~tg/mL and KARl inhibitory activity at 200 μg/mL. However, compounds exhibited poor insecticidal activity against oriental armyworm at 200 μg/mL in the preliminary studies. The research results will provide useful information for the design and discovery of new agro- chemicals with novel heterocyclic structures.展开更多
A series of novel title compounds 6a-6r and 7a-7c have been synthesized by Mannich reaction of the new triazole Schiff base intermidiates, substituted piperazine and formaldehyde under mild conditions in excellent yie...A series of novel title compounds 6a-6r and 7a-7c have been synthesized by Mannich reaction of the new triazole Schiff base intermidiates, substituted piperazine and formaldehyde under mild conditions in excellent yields. The crystal structure of compound 6i was determined to show a chair conformation of the piperazine ring and an （E）-configuration of the C=N double bond. The bioassay results indicated that most of the newly synthesized compounds exhibited excellent in vitro inhibitory activities and broader spectrum against several plant fungi, and were more effective than the control Triadimefon. Several compounds also displayed favourable in vivo antifungal activities. The relationships between the compound structures and various biological activities were discussed. Furthermore, the CoMFA calculation based on the antifungal activity data of compounds 6 against R. cerealis was carried out to establish a 3D-QSAR model, which revealed that steric and electrostatic fields were two most important factors for contributing the bioactivity of the compounds. The present work will provide significant information for guiding optimization of such new structures to develop novel agrochemicals with higher antifungal activities.展开更多
We have synthesized mannich base cyclohexanone using microwave irradiation method,and studied their pharma-cological activity.Based on analytical and spectral(IR,NMR and Mass) data,a number of mono as well as double m...We have synthesized mannich base cyclohexanone using microwave irradiation method,and studied their pharma-cological activity.Based on analytical and spectral(IR,NMR and Mass) data,a number of mono as well as double mannich base cyclohexanones have been synthesized from primary and secondary amines and formaldehyde,and then purified and characterized. The required 3-aryl-2,4-diacetyl-5-hydroxy-5-methylcyclohexanone was prepared from appropriate aldehyde and acetylacetone. The synthesized compounds were screened for analgesic activity via standard approaches,and they have shown positive analgesic activity.展开更多
The vanadium（V） peroxo complexes containing Mannich base ligands having composition Na[VO（O2）2（L-L）]·H2O [where L-L=morpholinobenzyl acetamide （MBA）, piperidinobenzyl acetamide （PBA）, morpholinobenzyl b...The vanadium（V） peroxo complexes containing Mannich base ligands having composition Na[VO（O2）2（L-L）]·H2O [where L-L=morpholinobenzyl acetamide （MBA）, piperidinobenzyl acetamide （PBA）, morpholinobenzyl benzamide （MBB）, piperidinobenzyl benzamide （PBB）, morpholinomethyl benzamide （MMB）, piperidinomethyl benzamide （PMB）, morpholinobenzyl formamide （MBF）, piperdinobenzyl formamide （PBF）] have been reported. The complexes have been prepared by stirring vanadium pentoxide with excess of 30% aque- ous-H202 followed by treatment with ethanolic solution of the ligand and finally maintained the pH of the reaction mixture by adding dilute solution of sodium hydroxide. The synthesized complexes have been characterized by various physico-chemical techniques, via elemental analysis, molar conductivity, magnetic susceptibility measure- ments, infra red, electronic, mass, ~H NMR spectral and TGA/DTA studies. These studies revealed that the synthesized complexes are uni-univalent electrolytes and diamagnetic in nature. The ligands are bound to metal in a bi- dentate mode through carbonyl oxygen and the ring nitrogen. Thermal analysis result provides conclusive evidence for the presence of one molecule of lattice water in the complexes. Mass spectra confirm the molecular mass of the complexes.展开更多
A series of Mannich bases were synthesized by a three-component Mannich reaction. The newly synthesized compounds were well characterized by elemental analyses, IR, NMR and mass spectroscopic studies. The potential an...A series of Mannich bases were synthesized by a three-component Mannich reaction. The newly synthesized compounds were well characterized by elemental analyses, IR, NMR and mass spectroscopic studies. The potential antibacterial effects of the synthesized compounds were investigated using standard bacterial strains： Gram-positive and Gram-negative bacteria. Interestingly, all the synthesized compounds were observed to be promising leads, possessing moderate to significant inhibitory activity as compared to standard.展开更多
A series of novel polymethoxyflavone Marmich base derivatives 1--8 was synthesized by Mannich reaction of 5-hydroxy-3,7,3＇,4＇-tetramethoxyflavone 9 with various secondary aliphatic amines and formaldehyde. Their ace...A series of novel polymethoxyflavone Marmich base derivatives 1--8 was synthesized by Mannich reaction of 5-hydroxy-3,7,3＇,4＇-tetramethoxyflavone 9 with various secondary aliphatic amines and formaldehyde. Their acetylcholmesterase（AChE） inhibitory activities were evaluated. The results showed that most of them exhibited AChE inhibitory activity and especially piperidin-l-yl methyl substituent derivative 5（IC50=0.238 μmol/L） demon- strated stronger activity comparable with the positive control, neoeserinemethyl sulfate（IC50=1.39 μmol/L）, which is worthy of further development as an agent for Alzheimer＇s disease treatment.展开更多
A convenient and practicable method for the synthesis of the novel 2-（trifluoromethyl）-6-arylimidazo[2,1-b][1,3,4]-thiadiazole （bis-）Mannich base derivatives containing various substitutedpiperazine motif has been...A convenient and practicable method for the synthesis of the novel 2-（trifluoromethyl）-6-arylimidazo[2,1-b][1,3,4]-thiadiazole （bis-）Mannich base derivatives containing various substitutedpiperazine motif has been developed based on the fused-heterocycle intermediate. The new structures were identified through melting points, ^1H NMR, ^13C NMR, ^19F NMR, elemental analysis （or HRMS） and X-ray single-crystal diffraction. The pesticidal bioassays showed that some of compounds exhibited good fungicidal activities against Cercospora arachidicola, Physalospora piricola and Rhizoctonia cereali at 50 mg/L; some of them displayed favourable insecticidal activities against oriental armyworm （Mythimna separata Walker） at 200 rag/L, particularly, Vk and Vm with mortality rate of 75% and 80% respectively, could be considered as new insecticidal lead compounds for further structural optimization.展开更多
Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the cor...Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the corresponding products in high yields.展开更多
文摘A previous study was conducted on the synthesis and antibacterial evaluation of Mannich bases of 2-(thioalkyl)-1H-methylbenzimidazole derivatives. The results of this study showed that certain 2-(thioalkyl)-1H-methylbenzimidazole and 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl)benzimidazole derivatives possess antibacterial activities against clinical strains, such as Escherichia coli, Klebsiella pneumonia (Gram-negative bacteria), Staphylococcus aureus and Pseudomonas aeruginosa (Gram-positive bacteria). Following these favorable results, we extended the antibacterial evaluation of this series of molecules to environmental strains. The aim of this study was to assess the impact of the methyl-piperidine group fixed at position-1 of this new series of benzimidazoles on the antibacterial activity of environmental strains. In addition, we first evaluated the antibacterial activity of four 2-(thioalkyl)methylbenzimidazole derivatives and then that of five 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives. This study allowed us to show that compounds 1d and 1e could inhibit bacterial growth in vitro of the Enterobacteria P1 strain with inhibition diameters of 17.3 ± 0.6 mm and 10 ± 0.0 mm, respectively. However, addition of methyl-piperidinyl in this series showed that five (5) of 2-(thioalkyl)-methyl-1-(piperidin-1-ylmethyl) benzimidazole derivatives had an inhibitory effect on the in vitro growth of bacterial strains used except on Enterobacteria P2 with inhibition diameters between 10.0 ± 0.8 mm and 27.9 ± 1.4 mm. The introduction of the methyl-piperidinyl group at the 1-position of 2-(thioalkyl)-1H-methylbenzimidazole derivatives greatly improved the antibacterial activity against environmental bacteria such as Escherichia coli A1, A2, A3, and A4 and two Enterobacteria P1.
文摘Five new C-8 Mannich base derivatives of irisolidone 2a-2e were synthesized and their nitric oxide（NO）production inhibitory activity was evaluated.Compounds 2a,2b,2c and 2e displayed stronger activities in vitro than the parent compound irisolidone.
基金National Natural Science Foundation of China (29674915, 29844001).
文摘This paper describes a combinatorial Synthesis of the Mannich Bases in Solution through the Mannich reaction using 3 ketones, 5 amines and formaldehyde in solution and hydrochloride as a catalyst and then using a macroporous quarterized ammonium resin (CO32- form) as a scavenge agent to remove the acid catalyst when the Mannich reaction is completed. It was found by GC/MS analysis that the symmetrical ketone, such as acetone, in the Mannich reaction mainly produces one Mannich base; while the asymmetrical ketone, such as 2-pentanone, gives two Mannich bases. The reactivity depends on the tereo-hinder of both ketones and amines.
文摘Two new Mannich and Schiff base ligands namely： （1-（3＇-amino-methyl-1＇（H）-1＇,2＇,4＇-triazole）-3-（1＇（H）-l＇,2＇,4＇- triazole-3＇-yl） iminoisatin （Lt） and l-morpholinomethyl-3-（1＇（H）-1＇,2＇,4＇-triazolyl）iminoisatin （LII） were prepared from condensation reaction of the new Schiff base 3-（l＇（H）-l＇,2＇,4＇-triazole-3＇-yl）iminoisatin （SBH） （0.01 mol） with formaldehyde and 3-amino-l,2,4-triazole （3-At） or with formaldehyde and morpholine （0.01 mole each） respectively. Structures were characterized by tH NMR, CHN analyses, mass spectra and IR spectra. Metal complexes were synthesized by heating each ligand （0.02 mo with metal salts （0.01 moo in ethanol or ethanol： acetone mixture respectively. The formula of metal complexes were suggested depending on CHN and thermal analyses, metal and chloride contents, IR and UV-visible spectra, magnetic moments （laefr） and conductivity measurements. All complexes were of octahedral geometry except palladium （II） complexes which were square planar. The two ligands and some selected metal complexes showed various antibacterial and cytotoxic effects.
文摘A series of novel furan/thiophene and piperazine-containing 1,2,4-triazole Mannich bases and bis（1,2,4-triazole） Mannich bases have been conveniently synthesized via Mannich reaction with triazole Schiff bases, various pipera- zinc derivatives, and formaldehyde as intermediates in good yields. Their structures were characterized by melting points, ~H NMR, 13C NMR, IR and elemental analysis. The preliminary bioassay showed that most compounds ex- hibited significant in vitro and in vivo fungicidal activity against several test plant fungi. Among 32 new compounds, the trifluoromethyl-containing compounds showed superior activity than the methyl-containing ones. Several com- pounds, such as FS, F9, F10, G5, HT, 118, 13 and 14, were comparable with some commercial fungicides against different fungi during the present study and could be further structurally optimized. Meanwhile, several compounds showed good herbicidal activity against Brassica campestris at 100 ~tg/mL and KARl inhibitory activity at 200 μg/mL. However, compounds exhibited poor insecticidal activity against oriental armyworm at 200 μg/mL in the preliminary studies. The research results will provide useful information for the design and discovery of new agro- chemicals with novel heterocyclic structures.
基金supported by the National Natural Science Foundation of China(No. 21372133)Tianjin Natural Science Foundation(No. 17JCYBJC19900)
文摘A series of novel title compounds 6a-6r and 7a-7c have been synthesized by Mannich reaction of the new triazole Schiff base intermidiates, substituted piperazine and formaldehyde under mild conditions in excellent yields. The crystal structure of compound 6i was determined to show a chair conformation of the piperazine ring and an （E）-configuration of the C=N double bond. The bioassay results indicated that most of the newly synthesized compounds exhibited excellent in vitro inhibitory activities and broader spectrum against several plant fungi, and were more effective than the control Triadimefon. Several compounds also displayed favourable in vivo antifungal activities. The relationships between the compound structures and various biological activities were discussed. Furthermore, the CoMFA calculation based on the antifungal activity data of compounds 6 against R. cerealis was carried out to establish a 3D-QSAR model, which revealed that steric and electrostatic fields were two most important factors for contributing the bioactivity of the compounds. The present work will provide significant information for guiding optimization of such new structures to develop novel agrochemicals with higher antifungal activities.
文摘We have synthesized mannich base cyclohexanone using microwave irradiation method,and studied their pharma-cological activity.Based on analytical and spectral(IR,NMR and Mass) data,a number of mono as well as double mannich base cyclohexanones have been synthesized from primary and secondary amines and formaldehyde,and then purified and characterized. The required 3-aryl-2,4-diacetyl-5-hydroxy-5-methylcyclohexanone was prepared from appropriate aldehyde and acetylacetone. The synthesized compounds were screened for analgesic activity via standard approaches,and they have shown positive analgesic activity.
文摘The vanadium（V） peroxo complexes containing Mannich base ligands having composition Na[VO（O2）2（L-L）]·H2O [where L-L=morpholinobenzyl acetamide （MBA）, piperidinobenzyl acetamide （PBA）, morpholinobenzyl benzamide （MBB）, piperidinobenzyl benzamide （PBB）, morpholinomethyl benzamide （MMB）, piperidinomethyl benzamide （PMB）, morpholinobenzyl formamide （MBF）, piperdinobenzyl formamide （PBF）] have been reported. The complexes have been prepared by stirring vanadium pentoxide with excess of 30% aque- ous-H202 followed by treatment with ethanolic solution of the ligand and finally maintained the pH of the reaction mixture by adding dilute solution of sodium hydroxide. The synthesized complexes have been characterized by various physico-chemical techniques, via elemental analysis, molar conductivity, magnetic susceptibility measure- ments, infra red, electronic, mass, ~H NMR spectral and TGA/DTA studies. These studies revealed that the synthesized complexes are uni-univalent electrolytes and diamagnetic in nature. The ligands are bound to metal in a bi- dentate mode through carbonyl oxygen and the ring nitrogen. Thermal analysis result provides conclusive evidence for the presence of one molecule of lattice water in the complexes. Mass spectra confirm the molecular mass of the complexes.
文摘A series of Mannich bases were synthesized by a three-component Mannich reaction. The newly synthesized compounds were well characterized by elemental analyses, IR, NMR and mass spectroscopic studies. The potential antibacterial effects of the synthesized compounds were investigated using standard bacterial strains： Gram-positive and Gram-negative bacteria. Interestingly, all the synthesized compounds were observed to be promising leads, possessing moderate to significant inhibitory activity as compared to standard.
基金Supported by the National Natural Science Foundation of China（No.J1210040） and the Hunan Provincial Natural Science Foundation, China（No. 14JJ2048）.
文摘A series of novel polymethoxyflavone Marmich base derivatives 1--8 was synthesized by Mannich reaction of 5-hydroxy-3,7,3＇,4＇-tetramethoxyflavone 9 with various secondary aliphatic amines and formaldehyde. Their acetylcholmesterase（AChE） inhibitory activities were evaluated. The results showed that most of them exhibited AChE inhibitory activity and especially piperidin-l-yl methyl substituent derivative 5（IC50=0.238 μmol/L） demon- strated stronger activity comparable with the positive control, neoeserinemethyl sulfate（IC50=1.39 μmol/L）, which is worthy of further development as an agent for Alzheimer＇s disease treatment.
基金This work was supported by the National Key Research and Development Program of China （No. 2017YFD0200505）, the National Natural Science Foundation of China （Nos. 21372133 and 21772103）, and Tianjin Natural Science Foundation （No. 17JCYBJC19900）. We thank the teachers of the Biological Assay Center, Nankai University, for kind bioassay assistance of compounds.
文摘A convenient and practicable method for the synthesis of the novel 2-（trifluoromethyl）-6-arylimidazo[2,1-b][1,3,4]-thiadiazole （bis-）Mannich base derivatives containing various substitutedpiperazine motif has been developed based on the fused-heterocycle intermediate. The new structures were identified through melting points, ^1H NMR, ^13C NMR, ^19F NMR, elemental analysis （or HRMS） and X-ray single-crystal diffraction. The pesticidal bioassays showed that some of compounds exhibited good fungicidal activities against Cercospora arachidicola, Physalospora piricola and Rhizoctonia cereali at 50 mg/L; some of them displayed favourable insecticidal activities against oriental armyworm （Mythimna separata Walker） at 200 rag/L, particularly, Vk and Vm with mortality rate of 75% and 80% respectively, could be considered as new insecticidal lead compounds for further structural optimization.
文摘Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the corresponding products in high yields.
