Oxidations of piperazine, 1-methylpiperazine and 1-ethylpiperazine by bromamine-T (BAT) in buffered acidic medium have been kinetically studied at 303 K. The reaction shows a first-order dependence of the rate each on...Oxidations of piperazine, 1-methylpiperazine and 1-ethylpiperazine by bromamine-T (BAT) in buffered acidic medium have been kinetically studied at 303 K. The reaction shows a first-order dependence of the rate each on [BAT]0 and [piperazine]0, and an inverse fractional-order dependence on [H+]. The additions of halide ions and the reduction product of BAT, p-toluenesulfonamide, have no effect on the reaction rate. The variation of ionic strength of the solvent medium has no influence on the rate. Activation parameters have been evaluated from the Arrhenius and Eyring plots. A common mechanism consistent with the kinetic data has been proposed for all piperazines. The protonation constants of substrates have been evaluated. The Hammett linear free-energy relationship has been observed for the reaction with ρ = ?0.5 indicating that the electron-donating groups enhance the reaction rate by stabilizing the transition state. An isokinetic relationship observed shows β = 368 K indicating the dominance of enthalpy factors on the reaction rate.展开更多
We have designed and synthesized a series of new phthalimidopiperazines, biological activity test show that the target compounds(Ic, Ie, ii) can inhibit HIV-I RT with IC50 20.0, 43.8, and 63.7 mu M, respectively.
A catalyst-free and additive-free ring-opening reaction of polyfluoroalkyl peroxides,triethylenediamine(DABCO),and 1,2-dichloroethane(DCE)has been developed for the defluorinative synthesis of structurally diverse pip...A catalyst-free and additive-free ring-opening reaction of polyfluoroalkyl peroxides,triethylenediamine(DABCO),and 1,2-dichloroethane(DCE)has been developed for the defluorinative synthesis of structurally diverse piperazines featuring a fluoroenone framework and a N-chloroethyl-substituent with high Z-stereoselectivity.The success of this three-component reaction is attributed to the in situ generation of an active 1-(2-chloroethyl)-1,4-diazabicyclo[2.2.2]octan-1-ium(DABCO·DCE)salt,which judiciously acts as a formal N-(2-chloroethyl)piperazine equivalent in the defluorinative coupling with less-studied aliphatic fluorinated substances.Impressively,this reaction accomplishes multi-activation of robust C(sp^(3))-F,C(sp^(3))-Cl,C(sp^(3))-O,and C(sp^(3))-N bonds in a one-pot process,offering a practical platform for the late-stage functionalization of complex molecules.Furthermore,the resulting products can not only serve as versatile building blocks for the synthesis of fluorinated heterocycles,but also undergo C—Cl bond displacement transformations with N-,O-,and S-nucleophiles.展开更多
Despite the ongoing increase in the efficiency of perovskite solar cells(PSCs),residual lead iodide(PbI2and moisture sensitivity issues continue to constrain their further commercialization.Herein,we propose a thermal...Despite the ongoing increase in the efficiency of perovskite solar cells(PSCs),residual lead iodide(PbI2and moisture sensitivity issues continue to constrain their further commercialization.Herein,we propose a thermally mediated in situ repair and encapsulation strategy to construct high-performance PSCs by incorporating piperazine thioctic acid salt(TAPPZ)as a dopant into the perovskite precursor Thermally dissociated piperazine(PPZ)from TAPPZ integrates microcrystals to form larger grain(>2000 nm),while the carboxylic acid in thioctic acid(TA)and the amine salt in TAPPZ synergistically passivate and transform PbI_(2),significantly reducing its residual amount.Additionally,TAPPZ undergoe thermal self-crosslinking during perovskite annealing,enabling melt-polymerization to form in situ encapsulation for enhanced water resistance.The TAPPZ-incorporated device achieves a remarkable efficiency of 25.65% and exhibits excellent operational stability,retaining over 90% of its initial efficiency after 2000 h under ambient conditions(20-30℃,20%-30% relative humidity).This study provide new insights into the construction of high-performance perovskite solar cells by designing and synthe sizing multifunctional single molecules for in situ repair and encapsulation of perovskites.展开更多
The effect of the presence of trace SO_(2)in industrial flue gas on the amine-scrubbing-based absorption process for CO_(2)capture has been a matter of concern.This study aimed to investigate the effect of trace SO_(2...The effect of the presence of trace SO_(2)in industrial flue gas on the amine-scrubbing-based absorption process for CO_(2)capture has been a matter of concern.This study aimed to investigate the effect of trace SO_(2)on the CO_(2)capture process using piperazine-based amine absorbents,focusing on SO_(2)-resistance capability,SO_(2)/CO_(2)absorption selectivity,and cyclic stability.The presence of trace SO_(2)not only restrains CO_(2)absorption,but also promotes the formation of carbamate within the piperazine-based amine absorbents.Remarkably,the incorporation of aminoethyl group in piperazine-based amine absorbents can enhance the SO_(2)-resistance capability by promoting the formation of carbamate,while piperazine-based amine absorbents with hydroxyethyl group can promote the formation of bicarbonate to reduce the SO_(2)-resistance capability.The work offers valuable insights into the efficient application of novel amine absorbents for CO_(2)capture from practical industrial flue gas.展开更多
Aim To establish a sensitive HPLC method for determination of piperazine ferulate and to study its pharmacokinetics in healthy volunteers. Methods Piperazine ferulate was separated on a Shimadzu C_ 18 column with acet...Aim To establish a sensitive HPLC method for determination of piperazine ferulate and to study its pharmacokinetics in healthy volunteers. Methods Piperazine ferulate was separated on a Shimadzu C_ 18 column with acetic acid (0.1%)-methanol (60 ∶ 40, V/V) as mobile phase after liquid-liquid extraction, and detection was performed at 310 nm. Piperazine ferulate pharmacokinetic parameters after a single oral dose of 200 mg of piperazine ferulate dispersible tablets in 20 healthy male volunteers were calculate...展开更多
An interesting approach for the design of anti-allergies is rationally considered. It was proved that current anti-allergic drugs comprise piperazine and acrylic acid segments. In harmony with these findings, new prod...An interesting approach for the design of anti-allergies is rationally considered. It was proved that current anti-allergic drugs comprise piperazine and acrylic acid segments. In harmony with these findings, new products 5a-u were synthesized starting from conjugated 2-thiopheneacrylic acid with amino acid esters3a-g followed by coupling of their acid derivatives4a-g with some piperazine segments, with the aim to increase their biological activities and decrease side effects. The anti-allergic and anti-inflammatory activities of the products were evaluated and promising results were obtained.展开更多
As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategie...As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategies exploited. For one compound, a highly reactive intermediate of isothiocyanate was constructed to get the desired piperazinecarbothioamide. The synthesis of the other compound was completed sequentially through Friedel-Crafts acylation, coupling reaction and Michael addition. Both synthetic routes have short steps and acceptable yields, and such strategies can be applied to the synthesis of similar oioerazine-containin~ comoounds.展开更多
A cocrystal of diosgenin with piperazine in 2:1 stoichiometry was successfully synthesized.The solid form was prepared by liquid assisted grinding,slurry and crystallization methods.The cocrystal was characterized by ...A cocrystal of diosgenin with piperazine in 2:1 stoichiometry was successfully synthesized.The solid form was prepared by liquid assisted grinding,slurry and crystallization methods.The cocrystal was characterized by powder X-ray diffraction,differential scanning calorimetry,thermogravimetric analysis,Fourier transform infrared spectroscopy,and structure determined by single crystal X-ray diffraction,the hydrogen bonds formed into fish bone structure along the[010]direction and all the molecules packed into 3D layer structure along a axis.After formation of cocrystal,the solubility of diosgenin was improved,and the solubility value in 0.2%SDS solution was approximately 1.5 times as large as that of the parent material.展开更多
A series of fluorine- and piperazine-containing 1,2,4-triazole thione derivatives were synthesized by the Mannich reaction of triazole intermediates with various substituted piperazines and formaldehyde in high yields...A series of fluorine- and piperazine-containing 1,2,4-triazole thione derivatives were synthesized by the Mannich reaction of triazole intermediates with various substituted piperazines and formaldehyde in high yields. Structures of title compounds were confirmed by melting points, IR,~1H NMR,^（13）C NMR and elemental analysis. The preliminary bioassays for 17 novel title compounds showed that several compounds have significant fungicidal activity against Cercospora arachidicola, Physalospora piricola and Rhizoctonia cerealis at 50 mg/m L.展开更多
Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activat...Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA+PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA+PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA.展开更多
The absorption of acid gas using reactive amines is among the most widely used types of capturing technologies.However,the absorption process requires intensive energy expenditure majorly in the solvent regeneration p...The absorption of acid gas using reactive amines is among the most widely used types of capturing technologies.However,the absorption process requires intensive energy expenditure majorly in the solvent regeneration process.This study simultaneously evaluated the regeneration energy of MDEA and PZ/MDEA solvents in terms of heat of absorption,sensible heat,and vaporization heat.Aspen Hysys version 8.8 simulation tool is applied to model the full acid gas removal plant for the chemical absorption process.The new energy balance technique presents around the absorption and desorption columns to bring a new perspective of energy distribution in the capturing of acid gas plants.Sensitivity analysis of regeneration energy and its three contributors is performed at several operation parameters such as absorber and stripper pressures,lean amine circulation rate,solvent concentration,reflux ratio,and CO2 and H2 S concentrations.The results show that the heat of absorption of PZ/MDEA system is higher than that for MDEA system for the same operating conditions.The sensible heat is the main contributor in the required regeneration energy of MDEA solvent system.The simulation results have been validated against data taken from real plant and literature.The product specifications of our simulation corroborate with real plant data in an excellent approach;additionally,the profile temperature of the absorber and the stripper columns are in good agreement with literature.The overall results highlight the direction of the effects of each parameter on the heat of absorption,sensible heat,and vaporization heat.展开更多
A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO2).Piperazine(PZ)is used as the activator in diethano...A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO2).Piperazine(PZ)is used as the activator in diethanolamine(DEA)aqueous solutions.The developed model for corrosion takes into consideration the effect of fluid flow,transfer of charge and diffusion of oxidizing agents and operating parameters like temperature,activator concentration,CO2 loading and pH.The study consists of two major models:Vapor–liquid Equilibrium(VLE)model and electrochemical corrosion model.The electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk solution.The results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of metal.An increase in concentration of activator,increases the rate of corrosion of carbon steel in mixtures of activated DEA.展开更多
A soluble, poly（ethylene glycol）-supported piperazine catalyst was prepared. This soluble catalyst efficiently catalyzes the Knoevenagel condensation of various aromatic aldehydes with diethyl malonate or ethyl acet...A soluble, poly（ethylene glycol）-supported piperazine catalyst was prepared. This soluble catalyst efficiently catalyzes the Knoevenagel condensation of various aromatic aldehydes with diethyl malonate or ethyl acetoacetate in a homogeneous phase to afford the desired alkenes in good purity and yield with a facile work-up process. It was found that the polymer reagent could be repeatedly used at least four times without the too much loss of activity. The catalyst has shown a good activity, stability, and recycling capability.展开更多
A phosphorus-nitrogen containing flame retardant additive of poly（phosphoric acid piperazine）, defined as PPAP, was synthesized by the salt-forming reaction between anhydrous piperazine and phosphoric acid, and the ...A phosphorus-nitrogen containing flame retardant additive of poly（phosphoric acid piperazine）, defined as PPAP, was synthesized by the salt-forming reaction between anhydrous piperazine and phosphoric acid, and the dehydration polymerization under heating in nitrogen atmosphere. Its chemical structure was well characterized by Fourier transform infrared（FTIR） spectroscopy, ^（13）C and ^（31）P solid-state nuclear magnetic resonance measurements. The synthesized PPAP and curing agent m-phenylenediamine were blended into epoxy resin（EP） to prepare flame retardant EP thermosets. The effects of PPAP on the fire retardancy and thermal degradation behavior of cured EP/PPAP composites were investigated by limiting oxygen index（LOI）, vertical burning（UL-94）, thermogravimetric analysis/infrared spectrometry（TG-IR） and cone calorimeter tests. The morphologies and chemical compositions of char residues for cured epoxy resin were investigated by scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）, respectively. The results demonstrated that the flame retardant EP thermosets successfully passed UL-94 V-0 flammability rating and the LOI value was as high as 30.8% when incorporating 5 wt% PPAP into the EP thermosets. The TGA results indicated that the synthesized PPAP flame retardant additive possessed high thermal stability and excellent charring capability. Meanwhile, the incorporation of PPAP stimulated the epoxy resin matrix to decompose and charring ahead of time due to its catalytic decomposition effect, which led to a higher char yield at high temperature. The morphological structures and the analysis results of XPS for char residues of EP thermosets revealed that the introduction of PPAP benefited the formation of a sufficient, more compact and homogeneous char layer containing phosphorus-nitrogen flame retardant elements on the material surface during combustion. The formed char layer with high quality effectively prevented the heat transmission and diffusion, limited the production of combustible gases, and inhibited the emission of smoke, leading to the reduction of heat and smoke release.展开更多
Hydrothermal reactions of biphenyl-2,3,3A,5A-tetracarboxylic acid（H4bptc） with cobalt salt in the presence of 1,4-bis（2-pyridylmethyl）piperazin（bpmp） afforded one novel coordination polymer, namely, [Co（H2bptc...Hydrothermal reactions of biphenyl-2,3,3A,5A-tetracarboxylic acid（H4bptc） with cobalt salt in the presence of 1,4-bis（2-pyridylmethyl）piperazin（bpmp） afforded one novel coordination polymer, namely, [Co（H2bptc）（bpmp）0.5（H2O）]n（1）. Its structure was established by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra and TG analysis. Complex 1 crystallizes in monoclinic, space group P21/c with a = 11.4839（11）, b = 16.6690（16）, c = 11.5559（11） A, V = 2201.8（4） A3, Mr = 539.35, Dc = 1.627 g/cm^3, μ（MoK α） = 0.841 mm-1, F（000） = 1108, Z = 4, the final R = 0.0309 and w R = 0.0705 for 4090 observed reflections（I 2σ（I））. Complex 1 displays a one-dimensional（1D） chain bridged by bpmp. Two carboxylic groups of H4 bptc ligand adopt μ01-η1：η1 and μ1-η1：η coordination modes to bridge adjacent Co（Ⅱ） ions together with bpmp ligand to give alternately arranged left- and right-handed helical chains. In addition, variable-temperature magnetic susceptibility measurements indicate that complex 1 shows weak antiferromagnetic interactions between the adjacent Co（Ⅱ） ions.展开更多
Objective:The present study was carried out to investigate the phytochemical constituents,in vitro antioxidant potential and anthelmintic activities of Flacourtia sepiaria Roxb leaves.Methods:The dried powdered leaves...Objective:The present study was carried out to investigate the phytochemical constituents,in vitro antioxidant potential and anthelmintic activities of Flacourtia sepiaria Roxb leaves.Methods:The dried powdered leaves of Flacourtia sepiaria were extracted using petroleum ether,chloroform,ethyl acetate and methanol by a soxhlet extractor and preliminary phytochemical screening was performed using standard protocols.All the extract was evaluated for their potential antioxidant activities using test such as DPPH,superoxide anion radical,hydroxyl radical,nitric oxide radical scavenging abilities,ferrous chelating ability and total phenolic and flavanoid content.Anthelmintic activity of extract was screened in adult Indian earthworm model.Results:Preliminary screening revealed the presence of bioactive compounds especially phenolics,tannins and terpenoids in all extracts.The phenolic and flavanoid content was highest in methanolic extract and lowest in petroleum ether extract.The paralytic(9.4610.212)and death time(31.43±1.148)of methanolic extract was found to be significant(P<0.05)when compared with paralytic(7.33±0.206)and death lime(18.60±0.229)of standard piperazine citrate at 100 mg/mL concentration.Conclusions:The results of the present study indicate that the leaf extracts of Flacourtia sepiaria exhibited strong antioxidant activity and possess significant anthelmintic activity and thus it is a good source of antioxidant and anthelmintic constituents.展开更多
A series of piperazine-based Gemini and Bola surfactants were synthesized. Gemini 1 and 5 have well surface activities. Their critical micelle concentrations （cmc） is 6.47×10^-4 mol/L and 1.17×10^-3mol/L, ...A series of piperazine-based Gemini and Bola surfactants were synthesized. Gemini 1 and 5 have well surface activities. Their critical micelle concentrations （cmc） is 6.47×10^-4 mol/L and 1.17×10^-3mol/L, respectively. Bola surfactants 2 and compound 3, possessing better water solubility, have lower surface activities. Calculation, carried out by MM2 energy minimization, showed that compound with more hydrophobic chains in a spacer of limited length is difficult to be synthesized.展开更多
Two series of 1-（benzoxazole-2-yl）piperazine （Sa-i） and 4-（benzoxazole-2-yl）piperidine compounds （10a-i） were designed, synthesized and evaluated for their α1-AR antagonistic activities. Biological assay in v...Two series of 1-（benzoxazole-2-yl）piperazine （Sa-i） and 4-（benzoxazole-2-yl）piperidine compounds （10a-i） were designed, synthesized and evaluated for their α1-AR antagonistic activities. Biological assay in vitro indicated that 10h showed slightly stronger α1-AR antagonistic activity to that of our lead compound 1.展开更多
A rapid analysis method of piperazine ferulate tablets by optic-fiber sensing technology with UV-vis absorption spectrum was established. Qualitative and quantitative data were obtained and compared by maximum and min...A rapid analysis method of piperazine ferulate tablets by optic-fiber sensing technology with UV-vis absorption spectrum was established. Qualitative and quantitative data were obtained and compared by maximum and minimum wavelength, absorbance and contrast spectra. Similarity method was used to identify authenticity of drugs. The difference of contents measured by this method and UV determination method in China Pharmacopoeia showed no statistical significance (P40.05), while the similarity can be used as a parameter to identify the authenticity of drugs.展开更多
文摘Oxidations of piperazine, 1-methylpiperazine and 1-ethylpiperazine by bromamine-T (BAT) in buffered acidic medium have been kinetically studied at 303 K. The reaction shows a first-order dependence of the rate each on [BAT]0 and [piperazine]0, and an inverse fractional-order dependence on [H+]. The additions of halide ions and the reduction product of BAT, p-toluenesulfonamide, have no effect on the reaction rate. The variation of ionic strength of the solvent medium has no influence on the rate. Activation parameters have been evaluated from the Arrhenius and Eyring plots. A common mechanism consistent with the kinetic data has been proposed for all piperazines. The protonation constants of substrates have been evaluated. The Hammett linear free-energy relationship has been observed for the reaction with ρ = ?0.5 indicating that the electron-donating groups enhance the reaction rate by stabilizing the transition state. An isokinetic relationship observed shows β = 368 K indicating the dominance of enthalpy factors on the reaction rate.
文摘We have designed and synthesized a series of new phthalimidopiperazines, biological activity test show that the target compounds(Ic, Ie, ii) can inhibit HIV-I RT with IC50 20.0, 43.8, and 63.7 mu M, respectively.
基金the financial support from the National Natural Science Foundation of China(22001121)Nanjing Tech University。
文摘A catalyst-free and additive-free ring-opening reaction of polyfluoroalkyl peroxides,triethylenediamine(DABCO),and 1,2-dichloroethane(DCE)has been developed for the defluorinative synthesis of structurally diverse piperazines featuring a fluoroenone framework and a N-chloroethyl-substituent with high Z-stereoselectivity.The success of this three-component reaction is attributed to the in situ generation of an active 1-(2-chloroethyl)-1,4-diazabicyclo[2.2.2]octan-1-ium(DABCO·DCE)salt,which judiciously acts as a formal N-(2-chloroethyl)piperazine equivalent in the defluorinative coupling with less-studied aliphatic fluorinated substances.Impressively,this reaction accomplishes multi-activation of robust C(sp^(3))-F,C(sp^(3))-Cl,C(sp^(3))-O,and C(sp^(3))-N bonds in a one-pot process,offering a practical platform for the late-stage functionalization of complex molecules.Furthermore,the resulting products can not only serve as versatile building blocks for the synthesis of fluorinated heterocycles,but also undergo C—Cl bond displacement transformations with N-,O-,and S-nucleophiles.
基金supported by the National Natural Science Foundation of China(22238002 and 22208047)the China Postdoctoral Science Foundation(2024T170086 and 2022M720639)+1 种基金the Research and Innovation Team Project of Dalian University of Technology(DUT2022TB10)the Fundamental Research Funds for the Central Universities(DUT22LAB610)。
文摘Despite the ongoing increase in the efficiency of perovskite solar cells(PSCs),residual lead iodide(PbI2and moisture sensitivity issues continue to constrain their further commercialization.Herein,we propose a thermally mediated in situ repair and encapsulation strategy to construct high-performance PSCs by incorporating piperazine thioctic acid salt(TAPPZ)as a dopant into the perovskite precursor Thermally dissociated piperazine(PPZ)from TAPPZ integrates microcrystals to form larger grain(>2000 nm),while the carboxylic acid in thioctic acid(TA)and the amine salt in TAPPZ synergistically passivate and transform PbI_(2),significantly reducing its residual amount.Additionally,TAPPZ undergoe thermal self-crosslinking during perovskite annealing,enabling melt-polymerization to form in situ encapsulation for enhanced water resistance.The TAPPZ-incorporated device achieves a remarkable efficiency of 25.65% and exhibits excellent operational stability,retaining over 90% of its initial efficiency after 2000 h under ambient conditions(20-30℃,20%-30% relative humidity).This study provide new insights into the construction of high-performance perovskite solar cells by designing and synthe sizing multifunctional single molecules for in situ repair and encapsulation of perovskites.
基金supported by the Major Science and Technology Project of Anhui Province(201903a07020004)the National Natural Science Foundation of China(22208078)the Fundamental Research Funds for the Central Universities(JZ2023HGTB0226).
文摘The effect of the presence of trace SO_(2)in industrial flue gas on the amine-scrubbing-based absorption process for CO_(2)capture has been a matter of concern.This study aimed to investigate the effect of trace SO_(2)on the CO_(2)capture process using piperazine-based amine absorbents,focusing on SO_(2)-resistance capability,SO_(2)/CO_(2)absorption selectivity,and cyclic stability.The presence of trace SO_(2)not only restrains CO_(2)absorption,but also promotes the formation of carbamate within the piperazine-based amine absorbents.Remarkably,the incorporation of aminoethyl group in piperazine-based amine absorbents can enhance the SO_(2)-resistance capability by promoting the formation of carbamate,while piperazine-based amine absorbents with hydroxyethyl group can promote the formation of bicarbonate to reduce the SO_(2)-resistance capability.The work offers valuable insights into the efficient application of novel amine absorbents for CO_(2)capture from practical industrial flue gas.
文摘Aim To establish a sensitive HPLC method for determination of piperazine ferulate and to study its pharmacokinetics in healthy volunteers. Methods Piperazine ferulate was separated on a Shimadzu C_ 18 column with acetic acid (0.1%)-methanol (60 ∶ 40, V/V) as mobile phase after liquid-liquid extraction, and detection was performed at 310 nm. Piperazine ferulate pharmacokinetic parameters after a single oral dose of 200 mg of piperazine ferulate dispersible tablets in 20 healthy male volunteers were calculate...
文摘An interesting approach for the design of anti-allergies is rationally considered. It was proved that current anti-allergic drugs comprise piperazine and acrylic acid segments. In harmony with these findings, new products 5a-u were synthesized starting from conjugated 2-thiopheneacrylic acid with amino acid esters3a-g followed by coupling of their acid derivatives4a-g with some piperazine segments, with the aim to increase their biological activities and decrease side effects. The anti-allergic and anti-inflammatory activities of the products were evaluated and promising results were obtained.
基金National Basic Research Program of China(Grant No.2012CB518000)the National Natural Science Foundation of China(Grant No.21172012)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120001110010)
文摘As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategies exploited. For one compound, a highly reactive intermediate of isothiocyanate was constructed to get the desired piperazinecarbothioamide. The synthesis of the other compound was completed sequentially through Friedel-Crafts acylation, coupling reaction and Michael addition. Both synthetic routes have short steps and acceptable yields, and such strategies can be applied to the synthesis of similar oioerazine-containin~ comoounds.
基金support by National Key research and development Program of China(Grant No.2016YFC1000900)CAMS Innovation Found for Medical Sciences(Grant No.2017-I2M-1-010)+1 种基金Construction and application of technology integration system for efficient identification of natural/effective active small molecules(Grant No.2018ZX09711001-001)National Science and Technology Major Project of China(Grant No.2018ZX09711001-010).
文摘A cocrystal of diosgenin with piperazine in 2:1 stoichiometry was successfully synthesized.The solid form was prepared by liquid assisted grinding,slurry and crystallization methods.The cocrystal was characterized by powder X-ray diffraction,differential scanning calorimetry,thermogravimetric analysis,Fourier transform infrared spectroscopy,and structure determined by single crystal X-ray diffraction,the hydrogen bonds formed into fish bone structure along the[010]direction and all the molecules packed into 3D layer structure along a axis.After formation of cocrystal,the solubility of diosgenin was improved,and the solubility value in 0.2%SDS solution was approximately 1.5 times as large as that of the parent material.
基金supported by the National Natural Science Foundation of China (No. 21372133)‘‘111’’ Project of Ministry of Education of China (No. B06005)
文摘A series of fluorine- and piperazine-containing 1,2,4-triazole thione derivatives were synthesized by the Mannich reaction of triazole intermediates with various substituted piperazines and formaldehyde in high yields. Structures of title compounds were confirmed by melting points, IR,~1H NMR,^（13）C NMR and elemental analysis. The preliminary bioassays for 17 novel title compounds showed that several compounds have significant fungicidal activity against Cercospora arachidicola, Physalospora piricola and Rhizoctonia cerealis at 50 mg/m L.
文摘Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA+PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA+PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA.
文摘The absorption of acid gas using reactive amines is among the most widely used types of capturing technologies.However,the absorption process requires intensive energy expenditure majorly in the solvent regeneration process.This study simultaneously evaluated the regeneration energy of MDEA and PZ/MDEA solvents in terms of heat of absorption,sensible heat,and vaporization heat.Aspen Hysys version 8.8 simulation tool is applied to model the full acid gas removal plant for the chemical absorption process.The new energy balance technique presents around the absorption and desorption columns to bring a new perspective of energy distribution in the capturing of acid gas plants.Sensitivity analysis of regeneration energy and its three contributors is performed at several operation parameters such as absorber and stripper pressures,lean amine circulation rate,solvent concentration,reflux ratio,and CO2 and H2 S concentrations.The results show that the heat of absorption of PZ/MDEA system is higher than that for MDEA system for the same operating conditions.The sensible heat is the main contributor in the required regeneration energy of MDEA solvent system.The simulation results have been validated against data taken from real plant and literature.The product specifications of our simulation corroborate with real plant data in an excellent approach;additionally,the profile temperature of the absorber and the stripper columns are in good agreement with literature.The overall results highlight the direction of the effects of each parameter on the heat of absorption,sensible heat,and vaporization heat.
基金the financial support provided by the Ministry of Higher Education&Scientific Research of Iraq。
文摘A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO2).Piperazine(PZ)is used as the activator in diethanolamine(DEA)aqueous solutions.The developed model for corrosion takes into consideration the effect of fluid flow,transfer of charge and diffusion of oxidizing agents and operating parameters like temperature,activator concentration,CO2 loading and pH.The study consists of two major models:Vapor–liquid Equilibrium(VLE)model and electrochemical corrosion model.The electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk solution.The results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of metal.An increase in concentration of activator,increases the rate of corrosion of carbon steel in mixtures of activated DEA.
基金Supported by the National Natural Science Foundation of China(No.20872001)the Natural Science Foundation of Education Administration of Anhui Province,China(No.KJ2008A064)
文摘A soluble, poly（ethylene glycol）-supported piperazine catalyst was prepared. This soluble catalyst efficiently catalyzes the Knoevenagel condensation of various aromatic aldehydes with diethyl malonate or ethyl acetoacetate in a homogeneous phase to afford the desired alkenes in good purity and yield with a facile work-up process. It was found that the polymer reagent could be repeatedly used at least four times without the too much loss of activity. The catalyst has shown a good activity, stability, and recycling capability.
基金financially supported by the Fundamental Research Funds for the Central Universities (No.2572014EB06-02)National Natural Science Foundation of China (No.51673035)Heilongjiang Major Research Projects (No.GA15A101)
文摘A phosphorus-nitrogen containing flame retardant additive of poly（phosphoric acid piperazine）, defined as PPAP, was synthesized by the salt-forming reaction between anhydrous piperazine and phosphoric acid, and the dehydration polymerization under heating in nitrogen atmosphere. Its chemical structure was well characterized by Fourier transform infrared（FTIR） spectroscopy, ^（13）C and ^（31）P solid-state nuclear magnetic resonance measurements. The synthesized PPAP and curing agent m-phenylenediamine were blended into epoxy resin（EP） to prepare flame retardant EP thermosets. The effects of PPAP on the fire retardancy and thermal degradation behavior of cured EP/PPAP composites were investigated by limiting oxygen index（LOI）, vertical burning（UL-94）, thermogravimetric analysis/infrared spectrometry（TG-IR） and cone calorimeter tests. The morphologies and chemical compositions of char residues for cured epoxy resin were investigated by scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）, respectively. The results demonstrated that the flame retardant EP thermosets successfully passed UL-94 V-0 flammability rating and the LOI value was as high as 30.8% when incorporating 5 wt% PPAP into the EP thermosets. The TGA results indicated that the synthesized PPAP flame retardant additive possessed high thermal stability and excellent charring capability. Meanwhile, the incorporation of PPAP stimulated the epoxy resin matrix to decompose and charring ahead of time due to its catalytic decomposition effect, which led to a higher char yield at high temperature. The morphological structures and the analysis results of XPS for char residues of EP thermosets revealed that the introduction of PPAP benefited the formation of a sufficient, more compact and homogeneous char layer containing phosphorus-nitrogen flame retardant elements on the material surface during combustion. The formed char layer with high quality effectively prevented the heat transmission and diffusion, limited the production of combustible gases, and inhibited the emission of smoke, leading to the reduction of heat and smoke release.
基金supported by the National Natural Science Foundation of China(No.21273101 and 21302082)the Foundation of the Program for Backbone Teachers in Universities of Henan Province(No.2012GGJS158)
文摘Hydrothermal reactions of biphenyl-2,3,3A,5A-tetracarboxylic acid（H4bptc） with cobalt salt in the presence of 1,4-bis（2-pyridylmethyl）piperazin（bpmp） afforded one novel coordination polymer, namely, [Co（H2bptc）（bpmp）0.5（H2O）]n（1）. Its structure was established by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra and TG analysis. Complex 1 crystallizes in monoclinic, space group P21/c with a = 11.4839（11）, b = 16.6690（16）, c = 11.5559（11） A, V = 2201.8（4） A3, Mr = 539.35, Dc = 1.627 g/cm^3, μ（MoK α） = 0.841 mm-1, F（000） = 1108, Z = 4, the final R = 0.0309 and w R = 0.0705 for 4090 observed reflections（I 2σ（I））. Complex 1 displays a one-dimensional（1D） chain bridged by bpmp. Two carboxylic groups of H4 bptc ligand adopt μ01-η1：η1 and μ1-η1：η coordination modes to bridge adjacent Co（Ⅱ） ions together with bpmp ligand to give alternately arranged left- and right-handed helical chains. In addition, variable-temperature magnetic susceptibility measurements indicate that complex 1 shows weak antiferromagnetic interactions between the adjacent Co（Ⅱ） ions.
基金supported by University Grants Commission,India(Grant No.41-738/20)
文摘Objective:The present study was carried out to investigate the phytochemical constituents,in vitro antioxidant potential and anthelmintic activities of Flacourtia sepiaria Roxb leaves.Methods:The dried powdered leaves of Flacourtia sepiaria were extracted using petroleum ether,chloroform,ethyl acetate and methanol by a soxhlet extractor and preliminary phytochemical screening was performed using standard protocols.All the extract was evaluated for their potential antioxidant activities using test such as DPPH,superoxide anion radical,hydroxyl radical,nitric oxide radical scavenging abilities,ferrous chelating ability and total phenolic and flavanoid content.Anthelmintic activity of extract was screened in adult Indian earthworm model.Results:Preliminary screening revealed the presence of bioactive compounds especially phenolics,tannins and terpenoids in all extracts.The phenolic and flavanoid content was highest in methanolic extract and lowest in petroleum ether extract.The paralytic(9.4610.212)and death time(31.43±1.148)of methanolic extract was found to be significant(P<0.05)when compared with paralytic(7.33±0.206)and death lime(18.60±0.229)of standard piperazine citrate at 100 mg/mL concentration.Conclusions:The results of the present study indicate that the leaf extracts of Flacourtia sepiaria exhibited strong antioxidant activity and possess significant anthelmintic activity and thus it is a good source of antioxidant and anthelmintic constituents.
文摘A series of piperazine-based Gemini and Bola surfactants were synthesized. Gemini 1 and 5 have well surface activities. Their critical micelle concentrations （cmc） is 6.47×10^-4 mol/L and 1.17×10^-3mol/L, respectively. Bola surfactants 2 and compound 3, possessing better water solubility, have lower surface activities. Calculation, carried out by MM2 energy minimization, showed that compound with more hydrophobic chains in a spacer of limited length is difficult to be synthesized.
基金the National High-Tech Research and Development Plan(No.2002AA2Z3118)
文摘Two series of 1-（benzoxazole-2-yl）piperazine （Sa-i） and 4-（benzoxazole-2-yl）piperidine compounds （10a-i） were designed, synthesized and evaluated for their α1-AR antagonistic activities. Biological assay in vitro indicated that 10h showed slightly stronger α1-AR antagonistic activity to that of our lead compound 1.
文摘A rapid analysis method of piperazine ferulate tablets by optic-fiber sensing technology with UV-vis absorption spectrum was established. Qualitative and quantitative data were obtained and compared by maximum and minimum wavelength, absorbance and contrast spectra. Similarity method was used to identify authenticity of drugs. The difference of contents measured by this method and UV determination method in China Pharmacopoeia showed no statistical significance (P40.05), while the similarity can be used as a parameter to identify the authenticity of drugs.
