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
Wireless sensor Mobile ad hoc networks have excellent potential in moving and monitoring disaster area networks on real-time basis.The recent challenges faced in Mobile Ad Hoc Networks(MANETs)include scalability,local...Wireless sensor Mobile ad hoc networks have excellent potential in moving and monitoring disaster area networks on real-time basis.The recent challenges faced in Mobile Ad Hoc Networks(MANETs)include scalability,localization,heterogeneous network,self-organization,and self-sufficient operation.In this background,the current study focuses on specially-designed communication link establishment for high connection stability of wireless mobile sensor networks,especially in disaster area network.Existing protocols focus on location-dependent communications and use networks based on typically-used Internet Protocol(IP)architecture.However,IP-based communications have a few limitations such as inefficient bandwidth utilization,high processing,less transfer speeds,and excessive memory intake.To overcome these challenges,the number of neighbors(Node Density)is minimized and high Mobility Nodes(Node Speed)are avoided.The proposed Geographic Drone Based Route Optimization(GDRO)method reduces the entire overhead to a considerable level in an efficient manner and significantly improves the overall performance by identifying the disaster region.This drone communicates with anchor node periodically and shares the information to it so as to introduce a drone-based disaster network in an area.Geographic routing is a promising approach to enhance the routing efficiency in MANET.This algorithm helps in reaching the anchor(target)node with the help of Geographical Graph-Based Mapping(GGM).Global Positioning System(GPS)is enabled on mobile network of the anchor node which regularly broadcasts its location information that helps in finding the location.In first step,the node searches for local and remote anticipated Expected Transmission Count(ETX),thereby calculating the estimated distance.Received Signal Strength Indicator(RSSI)results are stored in the local memory of the node.Then,the node calculates the least remote anticipated ETX,Link Loss Rate,and information to the new location.Freeway Heuristic algorithm improves the data speed,efficiency and determines the path and optimization problem.In comparison with other models,the proposed method yielded an efficient communication,increased the throughput,and reduced the end-to-end delay,energy consumption and packet loss performance in disaster area networks.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
The coronavirus disease 2019(COVID-19)mortality rate in 55 African countries is almost 4.5 times lower than in the coronavirus disease 2019(COVID-19)despite Africa having over 4.2 times more people.This mortality para...The coronavirus disease 2019(COVID-19)mortality rate in 55 African countries is almost 4.5 times lower than in the coronavirus disease 2019(COVID-19)despite Africa having over 4.2 times more people.This mortality paradox is also evident when comparing Nigeria,a heavily populated,poorly vaccinated and weakly mandated country to Israel,a small,highly vaccinated and strictly mandated country.Nigeria has almost 4 times lower COVID mortality than Israel.In this Field of Vision perspective,I explain how this paradox has evolved drawing upon my academic,clinical and social experience.Since April 2020,I’ve developed and been using the Egyptian immune-modulatory Kelleni’s protocol to manage COVID-19 patients including pediatric,geriatric,pregnant,immune-compromised and other individuals suffering from multiple comorbidities.It’s unfortunate that severe acute respiratory syndrome coronavirus 2 is still evolving accompanied by more deaths.However in Africa,we’ve been able to live without anxiety or mandates throughout the pandemic because we trust science and adopted early treatment using safe,and effective repurposed drugs that have saved the majority of COVID-19 patients.This article represents an African and Egyptian tale of honor.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
以邻氨基二苯甲酮为原料,经两分子环化缩合反应制得6,12-二芳基二苯并[b,f][1,5]二氮杂环辛四烯(2a^2d);2a^2d经Li Al H4还原制得6,12-二芳基-5,6,11,12-四氢二苯并[b,f][1,5]二氮杂环辛(3a^3d);3a^3d与醛(或酮)反应,合成了一系列新型...以邻氨基二苯甲酮为原料,经两分子环化缩合反应制得6,12-二芳基二苯并[b,f][1,5]二氮杂环辛四烯(2a^2d);2a^2d经Li Al H4还原制得6,12-二芳基-5,6,11,12-四氢二苯并[b,f][1,5]二氮杂环辛(3a^3d);3a^3d与醛(或酮)反应,合成了一系列新型的多取代Trger’s base衍生物(4a^4d和5a^7a),其结构经1H NMR,13C NMR,HR-MS(ESI)和X-射线单晶衍射表征。通过分析架桥前后3a(CCDC:1498564)和6a(CCDC:1498555)的晶体结构,解释了该类化合物1H NMR中NCH质子及桥上取代基质子裂分的原因,并进一步证实了4~7为非C2轴对称结构。展开更多
During the synthesis of the derivatives of styryl ketonic Mannich bases, a side -product IM,other than the normal Mannich base MA, is obtained. Mannich reaction is further studied and the formation mechanism of produc...During the synthesis of the derivatives of styryl ketonic Mannich bases, a side -product IM,other than the normal Mannich base MA, is obtained. Mannich reaction is further studied and the formation mechanism of product IM is postulated and discussed on the basis of deuterium labelling.展开更多
The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transiti...The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transition energies of low-lying excited states and discuss the band characters. The results indicate that the calculated spectra are in good agreement with experimental values. On the other hand, our calculations for A-T and G-C pairs are very beneficial to understanding hydrogen bond properties of these pairs.展开更多
Four Schiff bases, from pyruvic acid (1) with amines containing N and S donor atoms, thiocarbohydrazide (2, 61%), 2-methyl-3-thiosemicarbazide (3, 26%), S-benzyldithiocarbazate (4, 51%) and S-n-octyldithiocarbazate (5...Four Schiff bases, from pyruvic acid (1) with amines containing N and S donor atoms, thiocarbohydrazide (2, 61%), 2-methyl-3-thiosemicarbazide (3, 26%), S-benzyldithiocarbazate (4, 51%) and S-n-octyldithiocarbazate (5, 63%) have been successfully synthesized. The conventional method was used and a series of novel linear and cyclic Schiff bases were obtained with or without catalyst. All the Schiff bases were fully characterized by CHN elemental analysis, FT-IR, 1H & 13C NMR, EI-MS and two of the Schiff bases were further characterized by X-ray crystallographic structure analysis. Compound 2 crystallizes in the triclinic space group P-1 and unit cell dimensions are: a = 4.1777(8), b = 5.9538(11), c = 13.458(3) Å, α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0439. Compound 3 crystallizes in the orthorhombic space group P n a 2(1) and unit cell dimensions are: a = 5.5992(2), b = 11.3962(5), c = 10.6473(5), α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0285. Compounds 2 and 3 were obtained as cyclic Schiff bases which are triazine derivatives.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.
文摘Wireless sensor Mobile ad hoc networks have excellent potential in moving and monitoring disaster area networks on real-time basis.The recent challenges faced in Mobile Ad Hoc Networks(MANETs)include scalability,localization,heterogeneous network,self-organization,and self-sufficient operation.In this background,the current study focuses on specially-designed communication link establishment for high connection stability of wireless mobile sensor networks,especially in disaster area network.Existing protocols focus on location-dependent communications and use networks based on typically-used Internet Protocol(IP)architecture.However,IP-based communications have a few limitations such as inefficient bandwidth utilization,high processing,less transfer speeds,and excessive memory intake.To overcome these challenges,the number of neighbors(Node Density)is minimized and high Mobility Nodes(Node Speed)are avoided.The proposed Geographic Drone Based Route Optimization(GDRO)method reduces the entire overhead to a considerable level in an efficient manner and significantly improves the overall performance by identifying the disaster region.This drone communicates with anchor node periodically and shares the information to it so as to introduce a drone-based disaster network in an area.Geographic routing is a promising approach to enhance the routing efficiency in MANET.This algorithm helps in reaching the anchor(target)node with the help of Geographical Graph-Based Mapping(GGM).Global Positioning System(GPS)is enabled on mobile network of the anchor node which regularly broadcasts its location information that helps in finding the location.In first step,the node searches for local and remote anticipated Expected Transmission Count(ETX),thereby calculating the estimated distance.Received Signal Strength Indicator(RSSI)results are stored in the local memory of the node.Then,the node calculates the least remote anticipated ETX,Link Loss Rate,and information to the new location.Freeway Heuristic algorithm improves the data speed,efficiency and determines the path and optimization problem.In comparison with other models,the proposed method yielded an efficient communication,increased the throughput,and reduced the end-to-end delay,energy consumption and packet loss performance in disaster area networks.
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The coronavirus disease 2019(COVID-19)mortality rate in 55 African countries is almost 4.5 times lower than in the coronavirus disease 2019(COVID-19)despite Africa having over 4.2 times more people.This mortality paradox is also evident when comparing Nigeria,a heavily populated,poorly vaccinated and weakly mandated country to Israel,a small,highly vaccinated and strictly mandated country.Nigeria has almost 4 times lower COVID mortality than Israel.In this Field of Vision perspective,I explain how this paradox has evolved drawing upon my academic,clinical and social experience.Since April 2020,I’ve developed and been using the Egyptian immune-modulatory Kelleni’s protocol to manage COVID-19 patients including pediatric,geriatric,pregnant,immune-compromised and other individuals suffering from multiple comorbidities.It’s unfortunate that severe acute respiratory syndrome coronavirus 2 is still evolving accompanied by more deaths.However in Africa,we’ve been able to live without anxiety or mandates throughout the pandemic because we trust science and adopted early treatment using safe,and effective repurposed drugs that have saved the majority of COVID-19 patients.This article represents an African and Egyptian tale of honor.
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.
基金the National Natural Science Foundation of China.
文摘During the synthesis of the derivatives of styryl ketonic Mannich bases, a side -product IM,other than the normal Mannich base MA, is obtained. Mannich reaction is further studied and the formation mechanism of product IM is postulated and discussed on the basis of deuterium labelling.
文摘The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transition energies of low-lying excited states and discuss the band characters. The results indicate that the calculated spectra are in good agreement with experimental values. On the other hand, our calculations for A-T and G-C pairs are very beneficial to understanding hydrogen bond properties of these pairs.
文摘Four Schiff bases, from pyruvic acid (1) with amines containing N and S donor atoms, thiocarbohydrazide (2, 61%), 2-methyl-3-thiosemicarbazide (3, 26%), S-benzyldithiocarbazate (4, 51%) and S-n-octyldithiocarbazate (5, 63%) have been successfully synthesized. The conventional method was used and a series of novel linear and cyclic Schiff bases were obtained with or without catalyst. All the Schiff bases were fully characterized by CHN elemental analysis, FT-IR, 1H & 13C NMR, EI-MS and two of the Schiff bases were further characterized by X-ray crystallographic structure analysis. Compound 2 crystallizes in the triclinic space group P-1 and unit cell dimensions are: a = 4.1777(8), b = 5.9538(11), c = 13.458(3) Å, α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0439. Compound 3 crystallizes in the orthorhombic space group P n a 2(1) and unit cell dimensions are: a = 5.5992(2), b = 11.3962(5), c = 10.6473(5), α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0285. Compounds 2 and 3 were obtained as cyclic Schiff bases which are triazine derivatives.