DMF Medium Research Articles

N-Substituted-2-butyl-5-chloro-3H-imidazole-4-carbaldehyde Derivatives as Anti-tumor Agents Against Ehrlich Ascites tumor Cells In Vivo

A new series of N-substituted 2-butyl-5-chloro-3H-imidazole-4-carbaldehyde derivatives were synthesized by using the different bioactive heteroaralkyl halides with 2-butyl-4-chloro-1H-imidazole-5-carbaldehyde in presence of powdered potassium carbonate in DMF medium. These compounds were screened for their antitumor activity. Our results show that treatment of imidazole derivatives inhibit proliferation EAT cells, decreases the ascites volume and increases the survivability of the animals in vivo. These compounds also inhibited the cellular proliferation of HUVEC cells in vitro by MTT assay. Further, these compounds could induce apoptosis, which is evident by the nuclear condensation of imidazole derivatives treated EAT cells in vivo by the cytological analysis. We have identified that pyrrolidine substituted imidazole derivative as potent anti-tumor compound. These inhibitors could represent as promising candidates for anticancer therapies, where the formation of peritoneal malignant ascites is a major cause of morbidity and mortality.

Heterodinuclear Ni(II)—Sn(II) complexes from reduced ONNO type Schiff base compounds

N,N´-bis(salicylidene)-1,3-propanediamine (LH2), N,N´-bis(salicylidene)-2,2´- dimethyl-1,3-propane-diamine (LDMH2), N,N´-bis(2-hydroxyacetophenylidene)-1,3-propanediamine (LACH2), N,N´-bis(2-hydroxyacetophenone)-2,2´-dimethyl-1,3-propanediamine (LACDMH2) and N,N´-bis(salicylidene)-1,2-ethylenediamine (SalenH2) were reduced in methanolic media with the help of NaBH4. Ni(II)—Sn(II) heteronuclear complexes were synthesized according to the template method in DMF media. The complex structures were analyzed using elemental analysis, FTIR spectroscopy, thermogravimetry and X-ray diffraction. Appropriate crystals for one of the complexes 2 were obtained for X-ray diffraction. The Ni(II) ion has an octahedral coordination between the organic donors. The Sn(II) ion forms three membered coordination structure with phenolic oxygen atoms via μ-bridges. The Ni … Sn bridging distance is 3.1543(9) Å.

Absorption spectral studies of 4f–4f transitions for the complexation of Pr(III) and Nd(III) with glutathione reduced (GSH) in presence of Zn(II) in different aquated organic solvents and kinetics for the complexation of Pr(III):GSH with Zn(II)

Abstract Comparative absorption and spectral analysis of 4f–4f transitions of the heterobimetallic complexation of glutathione reduced (GSH) with Pr(III) and Nd(III) in presence of Zn(II) has been explored in different aquated organic solvents like methanol (CH 3 OH), acetonitrile (CH 3 CN), dioxane, DMF and their equimolar mixtures. The variation in the energy parameters like Slater Condon ( F K ), Racah ( E K ) and Lande ( ξ 4f ), Nephelauxetic parameter ( β ) bonding parameter ( b 1/2 ) and percent covalency parameter ( δ ) are computed to explain the nature of complexation. The values of experimentally calculated oscillator strengths ( P ) and computed values of Judd–Ofelt electric dipole intensity parameters, T λ ( λ = 2, 4, 6) are studied for different 4f–4f transitions in different experimental conditions. The changes in the values of oscillator strengths ( P ) and T λ parameters also suggest the specific correlation between relative intensities, ligand structures and nature of interaction of Pr(III) and Nd(III) with GSH in presence of Zn(II). Kinetics for the formation of the complex, Pr(III):GSH:Zn(II) have also been studied at different temperatures in DMF medium and activation energy ( E a ) of the complexation is calculated.

Optimization and Validation of Quantitative Spectrophotometric Methods for the Determination of Alfuzosin in Pharmaceutical Formulations

Three accurate, simple and precise spectrophotometric methods for the determination of alfuzosin hydrochloride in bulk drugs and tablets are developed. The first method is based on the reaction of alfuzosin with ninhydrin reagent in N, N′‐dimethylformamide medium (DMF) producing a colored product which absorbs maximally at 575 nm. Beer’s law is obeyed in the concentration range 12.5‐62.5 µg/mL of alfuzosin. The second method is based on the reaction of drug with ascorbic acid in DMF medium resulting in the formation of a colored product, which absorbs maximally at 530 nm. Beer’s law is obeyed in the concentration 10‐50 µg/mL of alfuzosin. The third method is based on the reaction of alfuzosin with p‐benzoquinone (PBQ) to form a colored product with λmax at 400 nm. The products of the reaction were stable for 2 h at room temperature. The optimum experimental parameters for the reactions have been studied. The validity of the described procedures was assessed. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed methods could be used for the determination of alfuzosin in pharmaceutical formulations. The procedures were rapid, simple and suitable for quality control application.

Reactivity of per- O-acetylated 1-thioglycosides and glycosyl sulfones towards chromium(II) complexes in aqueous medium

Anomeric carbon–sulfur bonds in 1-thioglycosides and glycosyl sulfones can be cleaved by chromium(II) complexes in water–DMF medium. Anomeric radicals as well as sugar–chromium(III) complex intermediates can be generated in these reactions, leading in some cases, to the exclusive formation of the corresponding glycals.

Synthesis and Antibacterial Evaluation of Some Theophylline Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Two new mononuclear Ni(II) complexes with reduced ONNO type Schiff base

Abstract N,N′-bis(salicylidene)-1,3-propanediamine (LH2) and N,N′-bis(salicylidene)-2,2′-dimethyl-1,3-propanediamine (DMLH2) were reduced to phenolic amines by using NaBH4. Mononuclear complexes were obtained with Ni (II) in a N3O6 coordination sphere with these amines and N3– ions, in DMF media. It was established with the XRD studies that the coordination spheres were distorted octahedral and the complex obtained with LH2 formed dimeric structures via phenolic OH bonds. The other complex was seen to have monomeric structure. The complexes were characterized by X-ray diffraction, elemental analysis, termogravimetry, IR spectroscopy and simple magnetic susceptibility (Gouy method). In addition, cyclic voltammetric studies have been performed.

Synthesis of 1‐(n‐Hexyl‐5‐one)‐2‐chlorobenzimidazole.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Studies on a New Binuclear Tungsten(IV)-pterin Complex Showing Reactivity Towards Trimethylamine N-oxide

The new compound [W2IVOCl2L2] · DMF (2) has been synthesized by a redox reaction between WOCl4 and 2-pivaloylamino-6-acetonylisoxanthopterin (H2L, 1) in DMF medium. It bas been characterized by elemental analysis, spectroscopy and electrochemistry. Its reactivity towards Me3N → O has been followed both kinetically and stoichiometrically. The reaction follows substrate saturation kinetics and a large negative entropy of activation value points towards involvement of an associative mechanism. 1H-n.m.r. and c.v. data throw light on the role of a redox ‘non-innocent’ pterin ligand (1), in conferring reducing properties on the W(IV) atoms of (2).

Complex Formation on the Surface of Tungsten on Its Chlorination in DMF Medium

IR spectroscopy and chromato-mass spectrometry were used to investigate the surface layer of tungsten after its chlorination in a medium of DMF containing water. The mechanism of this process is similar to that of the previously described chlorination of rhenium and molybdenum and is determined by the participation of a complex formed in the DMF-H2O-Cl2 system.

Time resolved fluorescence study of ketocyanine dye–β cyclodextrin interactions in aqueous and non-aqueous media

Steady-state and time-resolved fluorescence measurements have been made using a ketocyanine dye in heterogeneous media containing β-cyclodextrin (β-CD) in aqueous and N, N-dimethyl formamide (DMF) media. Values of equilibrium constant for complexation of the dye in the ground (S 0) state with β-CD in above two media have been determined. The equilibrium constant is found to be higher for non-aqueous medium. Decay characteristics of the excited state have been explained by assuming a two-state model. Probable orientation of the dye in cyclodextrin has been proposed. Rotational relaxation of the S 1 state of the dye have studied and the value of micro-viscosity for the β-CD in DMF medium have been determined. A comparison has been made with the value obtained from steady-state anisotropy studies.

Novel Aspects of the Reaction of 3-(Benzimidazol-2-yl)-2-iminocoumarins with Aromatic Aldehydes

The reaction of 3-(benzimidazol-2-yl)-2-iminocoumarins with aromatic aldehydes has been studied. The condensation products 7-aryl-7H-benzo[4,5]imidazo[1,2-c]benzopyrano[3,2-e]pyrimidines or 3-(benzimidazol-2-yl)coumarins are formed depending on the nature of the substituent in the starting 2-iminocoumarin and aldehyde. In DMF medium, 7-aryl-7H-benzo[4,5]imidazo[1,2-c]benzopyrano[3,2-e]pyrimidines isomerize to the corresponding 7-aryl-14H-benzo[4,5]imidazo[1,2-c]benzopyrano[3,2-e]pyrimidines. The effect of the substituent on the isomerization process has been studied and the reaction mechanisms are discussed.

Luminescence behavior of tetraaza macrocylic nickel (II) complexes and non-linear Stern–Volmer quenching

Macrocylic dicarbinolamine nickel (II) complexes with diimine moiety in their ligand exhibited luminescence, when irradiated at their charge transfer band. The Stern–Volmer (S–V) plots of one of the complexes in DMF medium exhibited positive curvature, when FeC1 3 was used as a quencher, while the same complex showed negative curvature when nitrobenzene was used as a quencher. The mechanism for the luminescence quenching of the macrocyclic complex has also been discussed.

Complex Formation During Molybdenum Chlorination in DMF Medium

IR and EPR studies of solutions formed after molybdenum chlorination in the medium of DMF revealed the diamagnetic Mo(VI) and paramagnetic Mo(V) complexes of composition R2[MoOCl5], where R is [(CH3)2NCOH2]+ (I) and [(CH3)2NH2]+ (II). The hydrolysis of complex II was found to give dimethyl-substituted ammonium chloride.

Direct and derivative spectrophotometric determination of cobalt with 5-bromosalicylaldehydethiosemicarbazone

A simple and sensitive spectrophotometric method is developed for the determination of cobalt in aqueous DMF medium. The metal ion forms a brown coloured complex with 5-bromosalicylaldehydethiosemicarbazone (5-BSAT) in acidic medium. The complex shows absorption maximum at 410 nm. Beer's law is obeyed in the range 0.29-5.89 μg ml - 1 of cobalt(II). A method for the determination of cobalt by third derivative spectrophotometry is also proposed. The methods have been employed successfully for the determination of cobalt in steel samples.

Reusuable polymer-anchored catalyst for carbonylation reaction: kinetics and mechanism for diphenylurea formation

The investigation of the catalytic activity of [RhA(CO) 2] (HA; anthranilic acid) and its polymer analogue [Rh(OOCC 6H 4NHCH 2-P)(CO) 2]; P=polystyrene moiety, towards the reductive carbonylation of nitrobenzene in DMF medium has been reported. The maximum yield and selectivity of diphenylurea was achieved using methanol as cosolvent under optimum reaction conditions. Spectroscopic and kinetic studies showed that the reaction proceeds through a species [RhA(C(O)OCH 3) 2] and the isocyanate formed at an intermediate stage is immediately scavenged by excess amine to form N, N′-diphenylurea. A tentative reaction mechanism based on the identification of reactive intermediates has been proposed for the carbonylation process.

Self-Organization of PEO-graft-Single-Walled Carbon Nanotubes in Solutions and Langmuir−Blodgett Films

Poly(ethylene oxide) (PEO), soluble in both water and many organic solvents, is grafted onto single-walled carbon nanotubes (SWNTs), and aggregation behaviors of the resulting PEO-graft-SWNT in solutions and in Langmuir−Blodgett (LB) films are investigated. SWNTs, cleaved by acid, are dispersed relatively well in DMF and water, but poorly in chloroform and THF. PEO-graft-SWNT was synthesized by treating acid-cut SWNTs with SOCl2, followed by a reaction with monoamine-terminated PEO in a DMF and water medium. Atomic force microscopy reveals that PEO and SWNT segments take expanded and extended conformations when freshly prepared PEO-graft-SWNTs are cast from water. When PEO-graft-SWNTs are dispersed in chloroform, each SWNT segment collapses into a globular aggregate. Aging the chloroform dispersion produces self-organized structures detectable by light scattering. Langmuir−Blodgett films made from this aged solution afford a surface-micelle structure in which the coagulated collapsed SWNT core is surround...

Reactions of calix[4]resorcinolarene anions with esters of carboxylic acids in H2O−DMF solvent

Reactions of calix[4]resorcinolarene anions withpara-nitrophenyl carboxylates in the H2O−DMF medium were studied. The kinetics of this process was measured by optical spectroscopy and potentiometric titration; the step of formation of acylated calixarene and the subsequent step of its hydrolysis were detected. Self-association of long-chain calixarenes into micelles decreases their reactivity with respect to that of the monomers.

A new type of polarographic catalytic wave of organic compound

The polamgraphic behavior and catalytic wave mechanism of medroprogestemne acetate (MPA) were studied in both aqueous and DMF media. In 0.2 mol/L acetic acid-sodium acetate (pH 5.0) buffer solution, the bond of MPA first undergoes le, lH+ reduction to form protonated free radical HMPA, the further reduction of HMPA in le,1H+ process is simultaneous with the dimerization reaction between HMPA and neutral molecular MPA. In DMF media containing 0.1 mol/L tetrabutylammonium tetrafluoborate (TBA.BF4), the bond of MPA shows two le, 1H+reduction waves, which are ascribed to the reduction of MPA and free radical MPA.-, respectively. Here, no dimerization reaction occurs. These processes produce the reduction wave of MPA. In the presence of oxidant KIO3,a polamgraphic catalytic wave of MPA is observable due to a chemical reaction between HMPA. or MPA.- and KIO3 as well as its intermediate species to regenerate MPA. The catalytic wave, which is caused by the reduction of organic compound itself and the chemical reaction between oxidant and organic intermediate free radical to regenerate original organic compound, is a new-type wave of organic compound. Under optimum experimental conditions, the sensitivity of MPA catalytic wave in the presence of KIO3 is an order of magnitude higher than that of its reduction wave. The catalytic wave can be used for analytical purpose. The calculated rate constant of catalytic reaction is 1.7 × 103 mol·L-1·s-1.

A new type of polarographic catalytic wave of organic compound——Studies on the polarographic catalytic wave of medroprogesterone acetate in the presence of KIO 3

The polarographic behavior and catalytic wave mechanism of medroprogesterone acetate ( MPA) were studied in both aqueous and DMF media. In 0.2 mol/L acetic acid-sodium acetate ( pH 5 .0 ) buffer solution, the C=C bond of MPA first undergoes le,lH+ reduction to form protonated free radical HMPA , the further reduction of HMPA in le,lH + process is simultaneous with the dimerization reaction between HMPA and neutral molecular MPA. In DMF media containing 0.1 mol/ L tetrabutylammonium tetrafluoborate ( TBA ·BF4 ) , the C=C bond of MPA shows two le, 1H+ reduction waves, which are ascribed to the reduction of MPA and free radical MPA" , respectively. Here, no dimerization reaction occurs. These processes produce the reduction wave of MPA. In the presence of oxidant KIO3, a polarographic catalytic wave of MPA is observable due to a chemical reaction between HMPA or MPA ~ and KIO3 as well as its intermediate species to regenerate MPA. The catalytic wave, which is caused by the reduction of organic compound itself and the chemical reaction between oxidant and organic intermediate free radical to regenerate original organic compound, is a new-type wave of organic compound. Under optimum experimental conditions, the sensitivity of MPA catalytic wave in the presence of KIO3 is an order of magnitude higher than that of its reduction wave. The catalytic wave can be used for analytical purpose. The calculated rate constant of catalytic reaction is 1.7 X103mol·-1·S-1 .