Showing papers in "Chinese Journal of Chemistry in 2009"
TL;DR: In this article, a new and efficient method for the synthesis of 1,8-dioxo-9-aryl-decahydroacridine derivatives was developed via a one-pot three component reaction of dimedone, aromatic aldehydes and ammonium acetate in the presence of ammonium chloride, or Zn(OAc)2·2H2O or L-proline separately in water in the short period of time and high yields.
Abstract: A new and efficient method for the synthesis of 1,8-dioxo-9-aryl-decahydroacridine derivatives was developed via a one-pot three component reaction of dimedone, aromatic aldehydes and ammonium acetate in the presence of ammonium chloride, or Zn(OAc)2·2H2O or L-proline separately in water in the short period of time and high yields.
65 citations
TL;DR: Using carbon nanotubes (CNT) as templete, CNT/ZnO nanocomposite was prepared by a solgel method and its structure was characterized by XRD, IR and TEM.
Abstract: Using carbon nanotubes (CNT) as templete, CNT/ZnO nanocomposite was prepared by a sol-gel method. Its structure was characterized by XRD, IR and TEM. The UV absorbing properties were detected by a UV spectrophotometer. Photo degradation of methyl red in aqueous solution was investigated by using CNT/ZnO nanocomposite as photocatalyst. The results showed that the nanocomposite was composed of carbon nanotubes coated evenly by ZnO particles, with a diameter of 50–60 nm. UV-vis spectra indicated that the as-prepared CNT/ZnO nanocomposite had absorption of visible light as well as ultraviolet light. 60% CNT-added nanocomposite had the highest degradation rate for methyl red under the sunlight irradiation.
58 citations
TL;DR: In this article, a series of anthranilic acid esters containing N-pyridylpyrazole were designed and synthesized for the purpose of finding environmentally benign insecticides with high activity, low toxicity and low residue.
Abstract: In search of environmentally benign insecticides with high activity, low toxicity and low residue, a novel series of anthranilic acid esters containing N-pyridylpyrazole were designed and synthesized All of the compounds were characterized and confirmed by IR, 1H NMR, MS and elemental analysis The single crystal structure of 14d was determined by X-ray diffraction The bioassay tests showed that the synthesized compounds exhibited good insecticidal activities against Mythimna separata Walker and Culex pipiens pallens
52 citations
TL;DR: In this article, a coprecipitation method was used to synthesize a Mg-Fe layered double hydroxide (LDH) with a molar ratio of 3:1 and the sorption removal of Pb(II) by the LDH sample from pb(NO3)2 solution.
Abstract: Mg-Fe layered double hydroxide (LDH) with a Mg/Fe molar ratio of 3:1 was synthesized by using a coprecipitation method and the sorption removal of Pb(II) by the LDH sample from Pb(NO3)2 solution was investigated. It was found that Mg-Fe LDH showed a good sorption ability for Pb(II) from Pb(NO3)2 solution, indicating that the use of LDH as a promising inorganic sorbent for the removal of heavy metal ions is possible. The sorption kinetics and the sorption isotherm of Pb(II) on the LDH sample obeyed the pseudo-second order kinetic model and Aranovich-Donohue equation, respectively. The sorption mechanism of Pb(II) on the LDH may be attributed to the surface-induced precipitation and the chemical binding adsorption, and the removal ability arising from the surface-induced precipitation is much higher than that from the chemical binding adsorption.
41 citations
TL;DR: In this paper, a series of 4-aryl-5,10-dihydro-4H-benzo[g]chromene derivatives were synthesized by a three-component reaction with aromatic aldehyde, 2-hydroxy-1,4-dhydronaphthalene, 1, 4-dione, and malononitrile catalyzed by triethylbenzylammonium chloride under solvent-free conditions.
Abstract: A series of 4-aryl-5,10-dihydro-4H-benzo[g]chromene-5,10-dione derivatives were synthesized by a three-component reaction with aromatic aldehyde, 2-hydroxy-1,4-dihydronaphthalene-1,4-dione, and malononitrile catalyzed by triethylbenzylammonium chloride under solvent-free conditions. The novel efficient method has the advantages of environmental friendliness, high yield, simple work-up and ease of operation.
39 citations
TL;DR: In this article, a silica-supported polyphosphoric acid (PPA-SiO2) catalyzed the reaction of anthranilamide with aryl aldehydes or ketones under solvent-free conditions to afford the corresponding 1,2,3,4-tetrahydro-4-quinazolinone derivatives.
Abstract: Silica-supported polyphosphoric acid (PPA-SiO2) catalyzed efficiently the reaction of anthranilamide with aryl aldehydes or ketones under solvent-free conditions to afford the corresponding 1,2,3,4-tetrahydro-4-quinazolinone derivatives. This work consistently has the advantages of excellent yields, short reaction time, simple experimental and work-up procedures. The heterogeneous catalyst could be recovered and recycled for several times without any loss of its activity.
35 citations
TL;DR: In this paper, the aromatic aldehydes underwent cross aldol condensation with cycloalkanones in the presence of a catalytic amount of nanoporous silica-based sulfonic acid (SiO2-Pr-SO3H) under solvent-free conditions to afford the corresponding α,α′-bis(substituted benzylidene)cycloalkansones in excellent yields with short reaction time without any side reactions.
Abstract: The aromatic aldehydes underwent cross aldol condensation with cycloalkanones in the presence of a catalytic amount of nanoporous silica-based sulfonic acid (SiO2-Pr-SO3H) under solvent-free conditions to afford the corresponding α,α′-bis(substituted benzylidene)cycloalkanones in excellent yields with short reaction time without any side reactions. This method is very general, simple and environmentally friendly in contrast with other existing methods. SiO2-Pr-SO3H was proved to be an efficient heterogeneous solid acid catalyst, which could be easily handled and removed from the reaction mixture by simple filtration, and also recovered and reused without loss of reactivity.
34 citations
TL;DR: The ability of tin(II) chloride dihydrate as a catalyst to promote the three-component condensation reaction from a diversity of aromatic aldehydes, 2-aminopyridines and isonitriles at room temperature is described in this article.
Abstract: The ability of tin(II) chloride dihydrate as a catalyst to promote the three-component condensation reaction from a diversity of aromatic aldehydes, 2-aminopyridines and isonitriles at room temperature is described. This methodology affords a number of 3-aminoimidazo[1,2-a]pyridines in the presence of tin(II) chloride dihydrate as a new and mild Lewis acid catalyst in the multi-component reaction in reasonable yields and short reaction time without any significant optimization of the reaction conditions.
30 citations
TL;DR: The first synthesis of three natural glycolipid simplexides 1a–1c, which were isolated from the marine sponge Plakortis simplex and claimed to inhibit T cell proliferation, has been concisely accomplished by a reactivity-based one-pot synthetic strategy under the use of p-toluenethioglycoside (STol) donors.
Abstract: The first synthesis of three natural glycolipid simplexides 1a–1c, which were isolated from the marine sponge Plakortis simplex and claimed to inhibit T cell proliferation, has been concisely accomplished by a reactivity-based one-pot synthetic strategy under the use of p-toluenethioglycoside (STol) donors.
29 citations
TL;DR: Trifluoromethanesulfonic acid (triflic acid) was found to be able to efficiently activate the benzylic sp3 C–F bond, and strong CF···H+ interaction or hydrogen bonding, is believed to play an important role in the current Br?nsted acid-mediated C-F bond activation chemistry.
Abstract: Trifluoromethanesulfonic acid (triflic acid) was found to be able to efficiently activate the benzylic sp3 C–F bond. Thus, under the catalysis of triflic acid at room temperature, trifluoromethylated arenes readily reacted with benzene to give benzophenones in moderate to good yields. Under similar B?nsted acid catalysis, intramolecular arylation also happened in the cases of some CF3-arene substrates bearing an additional nucleophilic aryl group. Strong CF···H+ interaction or hydrogen bonding, is believed to play an important role in the current Br?nsted acid-mediated C–F bond activation chemistry.
28 citations
TL;DR: Pd nanoparticles were generated in situ from PdCl2 in TBAF (n-Bu4NF), which displayed high efficiency for the Suzuki-Miyaura cross-coupling reaction, and aryl bromides could be consumed completely by aryLboronic acids in about 15–60 min.
Abstract: Pd nanoparticles were generated in situ from PdCl2 in TBAF (n-Bu4NF), which displayed high efficiency for the Suzuki-Miyaura cross-coupling reaction. In the presence of PdCl2 and TBAF, a variety of aryl halides were coupled with arylboronic acids smoothly in moderate to good yields. Moreover, the PdCl2/TBAF system could be recovered and reused several times in the Suzuki-Miyaura reaction, and aryl bromides could be consumed completely by arylboronic acids in about 15–60 min. It is noteworthy that these reactions were conducted under solvent-free, ligand-free and reusable conditions. Mechanism for the PdCl2/TBAF-catalyzed reactions was also discussed.
TL;DR: In this paper, the process of hydrazine oxidation and its kinetics were established by using cyclic voltammetry, chronoamperometry techniques as well as steady state polarization measurements.
Abstract: Electrocatalytic oxidation of hydrazine was investigated on a cobalt hydroxide modified glassy carbon (CHM-GC) electrode in alkaline solution The process of oxidation involved and its kinetics were established by using cyclic voltammetry, chronoamperometry techniques as well as steady state polarization measurements In cyclic voltammetry (CV) studies, in the presence of hydrazine the peak current increase of the oxidation of cobalt hydroxide is followed by a decrease in the corresponding cathodic current This indicates that hydrazine is oxidized on the redox mediator that is immobilized on the electrode surface via an electrocatalytic mechanism A mechanism based on the electrochemical generation of Co(IV) active sites and their subsequent consumption by the hydrazine in question was also investigated
TL;DR: In this article, a solgel method was used to synthesize ammonia from wet hydrogen and dry nitrogen at atmospheric pressure and low temperature (25-100 °C) with applied voltage, using SSM as a cathode, Ni-Ce0.8Sm 0.2O2−δ(Ni-SDC) as an anode, and silver-platinum film as a current collector, Nafion proton exchange membrane as a proton permeating membrane.
Abstract: Sm1.5Sr0.5MO4 (M=Ni, Co, Fe) (SSM) catalysts were prepared by a sol-gel method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was synthesized from wet hydrogen and dry nitrogen at atmospheric pressure and low temperature (25–100 °C) with applied voltage, using SSM as a cathode, Ni-Ce0.8Sm0.2O2−δ(Ni-SDC) as an anode, and silver-platinum film as a current collector, Nafion proton exchange membrane as a proton permeating membrane. Several important factors on ammonia synthesis were investigated and the optimal synthetic temperature was found, at which the highest rate of evolution of ammonia was up to 1.05×10−8 mol·cm−2·s−1.
TL;DR: In this article, an undivided cell containing n-Bu4NBr-DMF electrolyte at a constant current under room temperature was used to electrocarboxylate α-hydroxycarboxylic acids with CO2.
Abstract: With Ni as the cathode and Al as the anode, aromatic ketones (acetophenone, benzophenone, 6-methoxy-2-acetonaphthone, 4-methylacetophenone and 4-methoxyacetophenone) could be successfully electrocarboxylated with CO2 (4 MPa) in an undivided cell containing n-Bu4NBr-DMF electrolyte at a constant current under room temperature, affording the corresponding α-hydroxycarboxylic acids in good to excellent yields (56%–90%). The experimental results showed that the yields of the target products were strongly dependent on the nature of cathode materials and aromatic ketones as well as electrolytic conditions (such as electricity, substrate concentrations, conducting salts and solvents, CO2 pressure). In addition, it was found that the presence of protic agent such as water would lead to the increase of pinacol byproducts. The reaction mechanism was briefly discussed by CV experiments.
TL;DR: The feasibility of electrocarboxylation of benzyl chloride has been investigated at silver cathode in CO2-saturated room-temperature ionic liquid 1-butyl-3methylimidazolium tetrafluoroborate (BMIMBF4) solution for the first time as mentioned in this paper.
Abstract: The feasibility of electrocarboxylation of benzyl chloride has been investigated at silver cathode in CO2-saturated room-temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) solution for the first time. The electrochemical behavior was studied at different electrodes by cyclic voltammetry, which showed significant electrocatalytic effect of the silver electrode on the reduction of benzyl chloride. The highest yield of 45% of phenylacetic acid was obtained under optimal conditions. The recovered ionic liquid was reused for four times with gradual decrease in the yield of phenylacetic acid.
TL;DR: A concise total synthesis of (+/-)-yaequinolones A2 (2), a 2-quinolone alkaloid, has been accomplished through 6 steps from anthranilic acid with an overall yield of 27.8%.
Abstract: A concise total synthesis of (+/-)-yaequinolone A2 (2), a 2-quinolone alkaloid, has been accomplished through 6 steps from anthranilic acid with an overall yield of 27.8%. The synthetic strategy exploits highly diastereoselective intramolecular aldol addition of the MOM protected a-hydroxyanilide 7 as the key step.
TL;DR: In this paper, the anti-bacterial activities of four kinds of alkaloids in Rhizoma Coptidis, a traditional Chinese medicinal (TCM) herb, on Escherichia coli (E. coli) growth were investigated and compared by microcalorimetry.
Abstract: The anti-bacterial activities of four kinds of alkaloids in Rhizoma Coptidis, a traditional Chinese medicinal (TCM) herb, on Escherichia coli (E. coli) growth were investigated and compared by microcalorimetry. The four kinds of alkaloids were berberine, coptisine, palmatine and jatrorrhizine. The heat flow power-time curves of E. coli growth in the presence of the four kinds of alkaloids were measured using an LKB-2277 Bio-activity monitor using a stop-flow method, at 37°C. Then the thermal kinetic parameters such as, growth rate constant k, maximum power output of the log phase Pm,log and the stationary phase Pm,stat, growth inhibitory ratio I, generation time tg, total heat output of the log phase Qt,log and half-inhibitory concentration of the drugs, IC50, were obtained from the curves. The four kinds of alkaloids had different anti-E. coli activities. k, Pm,log and Qt,log of E. coli in the presence of the four kinds of alkaloids decreased with increasing concentrations of the alkaloids. Judged from the values of k, Pm,log, Qt,log, I and IC50, the experimental results revealed that the sequence of anti-bacterial activities of the four kinds of alkaloids was berberine>coptisine>palmatine>jatrorrhizine. The functional groups methylenedioxy at C-2 and C-3 on phenyl ring improved anti-bacterial activity more remarkably than methoxyl at C-2 and C-3 on the phenyl ring. However, the antibacterial activity did not vary significantly with methylenedioxy or methoxyl at C-9 and C-10 on the other phenyl ring.
TL;DR: An efficient guanylation of aromatic amine with carbodiimide in the presence of a catalytic amount of samarium diiodide, a Lewis-acid type precatalyst readily accessible, was developed, giving a variety of guanidines in good to excellent yields.
Abstract: An efficient guanylation of aromatic amine with carbodiimide in the presence of a catalytic amount of samarium diiodide, a Lewis-acid type precatalyst readily accessible, was developed. The reaction was carried out under mild conditions giving a variety of guanidines in good to excellent yields.
TL;DR: In this paper, a gas phase catalytic combustion of ethyl acetate, as one of volatile organic compounds (VOC), was studied on nanostructure ZSM-5, HZSM-4 and Co-ZSM5 with different cobalt loadings.
Abstract: Gas phase catalytic combustion of ethyl acetate, as one of volatile organic compounds (VOC), was studied on nanostructure ZSM-5, HZSM-5 and Co-ZSM-5 with different cobalt loadings Nanostructure of ZSM-5 was determined by XRD, SEM and TEM Catalytic studies were carried out under atmospheric pressure in a fixed bed reactor Results showed that the Co-ZSM-5 catalysts had better activity than others and at temperatures below 350 °C, amount of Co loading was more effective on catalytic activity The order of conversion of ethyl acetate over different Co loading is as follows: Co-ZSM-5 (075 wt%)
TL;DR: An electrochemical sensor was modified with multi-wall carbon nanotubes (MWCNT) and molecularly imprinted polymer (MIP) material synthesized with acrylamide and ethylene glycol dimethacrylate (EGDMA) in the presence of 1,3-dinitrobenzene (DNB) as the template molecule as discussed by the authors.
Abstract: An electrochemical sensor was modified with multi-wall carbon nanotubes (MWCNT) and molecularly imprinted polymer (MIP) material synthesized with acrylamide and ethylene glycol dimethacrylate (EGDMA) in the presence of 1,3-dinitrobenzene (DNB) as the template molecule. The MWCNT and MIP layers were successively modified on the surface of a glassy carbon electrode (GCE), of which the MIP film works as an artificial receptor due to its specific molecular recognition sites. The MIP material was characterized by FT-IR and electrochemical methods of square wave voltammetry (SWV). The interferences of other nitroaromatic compounds (NAC) such as 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB) and 2,4-dinitrotoluene (DNT) to DNB were also investigated by the prepared MIP/MWCNT electrode. Compared with other traditional sensors, the MIP/MWCNT modified electrode shows good selectivity and sensitivity. In addition, the current responses to DNB are linear with the concentration ranging from 4.5×10−8 to 8.5×10−6 mol/L with the detection limits of 2.5×10−8 (−0.58 V) and 1.5×10−8 mol/L (−0.69 V) (S/N=3). The construction process of MIP/MWCNT modified electrode was also studied as well. All results indicate that the MIP/MWCNT modified electrode established an improving way for simple, fast and selective analysis of DNB.
TL;DR: In this article, the Tishchenko reaction of various aldehydes to form corresponding esters was investigated and the reaction scope and the influence of lanthanide and sodium metal on the catalytic activity were investigated.
Abstract: The heterometal alkoxide clusters of Group 3 metal and lanthanides with sodium Ln2Na8(OCH2CH2NMe2)12(OH)2 (Ln=Y, lanthanide) were found to serve as highly active catalysts for the Tishchenko reaction of various aldehydes to form the corresponding esters. The reaction scope and the influence of lanthanide and sodium metal on the catalytic activity were investigated, and the proposed mechanism of the reaction was discussed.
TL;DR: In this paper, five new xanthones, garcinenone A (1), B (3), C (4), D (7) and E (8), along with seven known compounds were isolated from the EtOAc-soluble extract of the bark of Garcinia xanthochymus, and their structures were elucidated by spectroscopic methods, especially 2D-NMR techniques.
Abstract: Five new xanthones, garcinenone A (1), B (3), C (4), D (7) and E (8), along with 7 known compounds were isolated from the EtOAc-soluble extract of the bark of Garcinia xanthochymus, and their structures were elucidated by spectroscopic methods, especially 2D-NMR techniques. Jacareubin (2), 1,4,6-trihydroxy-5-methoxy-7-(3-methyl-2-butenyl)xanthone (6), subeliptenone B (11) and symphoxanthone (12) were obtained from this plant for the first time. The isolated compounds exhibited potent antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test with IC50 values in the 6.0–23.2 µmol/L. These results suggested that G. xanthochymus could be a promising rich source of natural antioxidant.
TL;DR: In this paper, a simple and efficient method for the synthesis of 1,8-dioxo-octahydroxanthene by using p-toluenesulfonic acid as a catalyst under solvent free conditions is described, which involves cyclization of 2,2-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1 one) that was obtained firstly by the reaction of dimedone with aromatic aldehydes in water as solvent and catalyst at room temperature.
Abstract: A simple and efficient method for the synthesis of 1,8-dioxo-octahydroxanthene by using p-toluenesulfonic acid as a catalyst under solvent free conditions is described, which involves cyclization of 2,2-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) that was obtained firstly by the reaction of dimedone with aromatic aldehydes in water as solvent and catalyst at room temperature. The experimental procedures in the two steps are very simple and the products are formed in excellent yields.
TL;DR: In this paper, a 1-Butyl-3methylimidazolium hydrogen sulfate (HSO4) was used as a catalyst for the formylation of primary alcohols in the presence of tertiary alcohols.
Abstract: 1-Butyl-3-methylimidazolium hydrogen sulfate [bmim]HSO4 as an acidic ionic liquid was prepared and used as a catalyst for the formylation of alcohols with ethyl formate at room temperature with good to excellent yields. A good selectivity was observed for the formylation of primary alcohols in the presence of tertiary alcohols.
TL;DR: In this article, a highly efficient method for specific synthesis of N-monomethylarylamines is presented, where anilines were treated with acetic anhydride and triethylamine in dry CH2Cl2 to give the corresponding acetamides.
Abstract: A highly efficient method for specific synthesis of N-monomethylarylamines is presented. Anilines were treated with acetic anhydride and triethylamine in dry CH2Cl2 to give the corresponding acetamides. The subsequent N-monomethylation of acetyl aryl amines with methyl iodide and NaH in THF introduced methyl group. Acid hydrolysis of the N-methyl acetanilides in ethylene glycol generated the corresponding N-methyl-N-aryl amines in high yields. This method was also used to synthesize (E)-2-bromo-5-(4-methylaminostyryl)pyridine that may be useful as an amyloid imaging agent for Alzheimer’s disease.
TL;DR: In this paper, two polymeric thin film modified electrodes, poly-niacinamide/glassy carbon electrode (poly-NA/GCE) and poly-nicotinic acid/glass carbon electrode, have been fabricated at glassy carbon electrodes by simple electropolymerization of niacinamide (NA) in different potential scan ranges of cyclic voltammetry (CV).
Abstract: Two polymeric thin film modified electrodes, poly-niacinamide/glassy carbon electrode (poly-NA/GCE) and poly-nicotinic acid/glassy carbon electrode (poly-NC/GCE), have be fabricated at glassy carbon electrodes by simple electropolymerization of niacinamide (NA) in different potential scan ranges of cyclic voltammetry (CV). These two electrodes all showed catalytic ability towards the oxidation of dopamine (DA), uric acid (UA) and ascorbic acid (AA) by obvious reductions of overpotentials, giving well-resolved voltammetric peaks, which allow simultaneously determination of DA, UA and AA. The poly-NC/GCE showed even higher electrocatalytic activity than the poly-NA/GCE. The electrochemical behavior of poly-NC/GCE was investigated by CV and differential pulse voltammetry (DPV) for determination of DA, UA and AA. The linear ranges of the concentration for the determination of AA, DA and UA using DPV were 75–3000, 0.37–16 and 0.741–230 mol·L−1, respectively. The slopes of the linear calibration curves for the detection were estimated to be 5.6, 1140 and 102 mA·L·mol−1 for AA, DA and UA, respectively. The poly-NC/GCE shows excellent sensitivity, good selectivity and antifouling properties.
TL;DR: In this article, the thermal behavior and non-isothermal kinetics of the exothermic decomposition reaction of 1-amino-1-hydrazino-2,2-dinitroethylene (AHDNE) were studied with DSC and TG/DTG methods.
Abstract: The thermal behavior and non-isothermal kinetics of the exothermic decomposition reaction of 1-amino-1-hydrazino-2,2-dinitroethylene (AHDNE) were studied with DSC and TG/DTG methods. The kinetic equation obtained is dα/dT=1019.29(1−α)exp(−1.88×104/T)/β. The critical temperature of thermal explosion is 98.16 °C. The specific heat capacity of AHDNE was determined, and the standard molar specific heat capacity is 211.86 J·mol−1·K−1 at 298.15 K. The adiabatic time-to-explosion of AHDNE was also calculated to be 59.21 s. AHDNE is unstable and has much lower thermostability than 1,1-diamino-2,2-dinitroethylene (FOX-7).
TL;DR: The binding interaction of captopril (CPL) with biologically active metal ions Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+ and Zn2+ was investigated in an aqueous acidic medium by fluorescence spectroscopy as discussed by the authors.
Abstract: The binding interaction of captopril (CPL) with biologically active metal ions Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+ and Zn2+ was investigated in an aqueous acidic medium by fluorescence spectroscopy. The experimental results showed that the metal ions quenched the intrinsic fluorescence of CPL by forming CPL-metal complexes. It was found that static quenching was the main reason for the fluorescence quenching. The quenching constant in the case of Cu2+ was highest among all quenchers, perhaps due to its high nuclear charge and small size. Quenching of CPL by metal ions follows the order Cu2+>Ni2+>Co2+>Ca2+>Zn2+>Mn2+>Mg2+. The quenching constant Ksv, bimolecular quenching constant Kq, binding constant K and the binding sites "n" were determined together with their thermodynamic parameters at 27 and 37°C. The positive entropy change indicated the gain in configurational entropy as a result of chelation. The process of interaction was spontaneous and mainly ΔS-driven.
TL;DR: In this article, the interaction of daunorubicin with calf thymus DNA has been investigated with the use of methylene blue dye as a spectral probe by the application of UV-Vis spectrophotometry, spectrofluorometry and voltammetry.
Abstract: The interaction of daunorubicin with calf thymus DNA has been investigated with the use of methylene blue dye as a spectral probe by the application of UV-Vis spectrophotometry, spectrofluorometry and voltammetry. The voltammetric behavior of daunorubicin has been investigated at a glassy carbon electrode using cyclic and differential pulse voltammetry. Both UV-vis spectrophotometry and cyclic voltammetry studies confirmed the intercalation reaction. The results showed that both daunorubicin and methylene blue molecules could intercalate into the double helix of DNA. The apparent binding constant of daunorubicin with DNA has been found to be 7.8 ×104 L·mol−1. The fluorescence signal of daunorubicin and methylene blue was quenched with DNA addition. The Stern-Volmer equation was plotted based on the quenching fluorescence signal of daunorubicin.
TL;DR: In this paper, a series of novel amides (sulfonamides) containing N-pyridylpyrazole were designed and synthesized and their chemical structures were characterized by 1H NMR, MS and elemental analysis or HRMS.
Abstract: In search of environmentally benign insecticides with high activity, low toxicity and low residual effects, a series of novel amides (sulfonamides) containing N-pyridylpyrazole were designed and synthesized. Their chemical structures were characterized by 1H NMR, MS and elemental analysis or HRMS. The bioassay tests indicated that some of these compounds exhibited moderate insecticidal activities against Mythimna separata Walker and Culex pipiens pallens.