Dimethylformamide In Presence Research Articles

Design, synthesis, and characterization of some novel pyrazolo [1,5‐a] pyrimidines as potent antimicrobial agents

Abstract magnified image A novel series of pyrazolo [1,5‐a] pyrimidines were synthesized by the condensation of substituted chalcones with 5‐amino pyrazole in presence of dimethyl formamide. All the synthesized products were characterized by the spectral analysis. Further, all newly synthesized compounds were screened for their antimicrobial activity. Most of the compounds showed potent activity. J. Heterocyclic Chem., (2010).

Enhanced activity and stability in the presence of organic solvents by increased active site polarity and stabilization of a surface loop in a metalloprotease

Salinivibrio zinc-metalloprotease (SVP) is an enzyme which was isolated from Salinivibrio proteolyticus, a moderately halophilic species from a hypersaline lake in Iran. A195E and G203D mutants were constructed to increase polarity near the active site in order to preserve the hydration layer against organic solvents [dimethylformamide (DMF), methanol, isopropanol and n-propanol]. A268P was constructed to stabilize a surface loop far from the active site and A195E/A268P was constructed to investigate the combined effects of these two mutations. Results showed that relative C(50) values of A195E increased to approximately 26 and 11% in DMF and methanol whereas an increase of approximately 32 and 41% was observed in the presence of isopropanol and n-propanol. The irreversible thermoinactivation rate (k(i)) for A195E was estimated to be 60 and 130 (x10(-3) min(-1)) in the presence of DMF and n-propanol, respectively, while k(i) for SVP was 90 and 190 (x10(-3) min(-1)). G203D exhibited similar k(i) as A195E in the presence of methanol and isopropanol, but the calculated k(i) in the presence of DMF and n-propanol was 70 and 160 (x10(-3) min(-1)), respectively. A268P and A268P/A195E variants marginally increased the thermoresistance of the enzyme in this condition.

Supramolecular isomerism of self-complementary zinc-5,10,15,20-tetra(4-pyridyl)porphyrin in the presence of dimethylformamide

Supramolecular isomerism by self-complementary coordination in the system zinc-5,10,15,20-tetra(4-pyridyl)porphyrin (ZnTPyP)–dimethylformamide (DMF) is reported. Recrystallization of ZnTPyP from DMF afforded crystals of a new tetrameric supramolecular isomer, [ZnTPyP]4·7.33DMF, with molecular and crystallographic S4 symmetry. The crystals were accompanied by triclinic crystals of [ZnTPyP·2DMF]n with a polymeric 1D ladder structure. In situ metalation of the parent free-base 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) with Zn2+ in dimethylformamide afforded monoclinic crystals of [ZnTPyP·2.33DMF]n with a 1D double zig-zag chain structure. The ZnTPyP–DMF system is an example of unusual supramolecular isomerism in metallosupramolecular chemistry.

Preparation, Characterization and Utilization of Amidoximated Poly(AN/MAA)-grafted Alhagi Residues for the Removal of Zn(II) Ions from Aqueous Solution

Radiation grafting by the mutual method of methacrylic acid/acrylonitrile (MAA/AN) onto Alhagi residues in the presence of dimethylformamide (DMF) as a solvent is discussed. The factors affecting the radiation graft copolymerization were investigated. These included radiation dose, co-monomer composition and concentration. The grafted samples were characterized using FT-IR spectroscopy and scanning electron microscopy (SEM), as well as by the estimation of their nitrogen and carboxyl group contents. The grafted samples were then amidoximated by treatment with hydroxylamine hydrochloride in an alkaline medium. Such amidoximated poly(MAA/AN)-grafted Alhagi residues were utilized for the removal of Zn(II) ions from aqueous solution by adsorption and the factors affecting such adsorption processes were studied. These factors were the pH of the adsorbate solution, the adsorbent dosage, the contact time and the adsorption temperature. The adsorption data obeyed the Langmuir and Freundlich isotherms. The Langmuir adsorption capacity (Qmax) of the amidoximated poly(MAA/AN)-grafted Alhagi residues towards Zn(II) ions was found to be 212.76 and 344.8 mg/g at 30 °C and 50 °C, respectively. Similarly, the Freundlich constants, KF and 1/n, at 30 °C were found to be 21.47 and 0.3489, respectively. The study showed that amidoximated poly(MAA/AN)-grafted Alhagi residues were effective in the adsorption of Zn(II) ions from aqueous solutions. The thermodynamics parameters of the adsorption process, viz. ΔH0, ΔG0 and ΔS0, were evaluated. The results showed that the adsorption of Zn(II) ions onto amidoximated poly(MAA/AN)-grafted Alhagi residues was endothermic and spontaneous. The adsorption data followed second-order kinetics.

Synthesis of some novel triazole derivatives as anti-nociceptive and anti-inflammatory agents

Eight novel 1-[2-(1H-tetrazol-5-yl)ethyl]-1H-benzo[d][1,2,3]triazoles (3a-h) have been synthesized in order to obtain new compounds with potential anti-nociceptive and anti-inflammatory activity. The titled compounds were synthesized by the condensation of 1-[2-(1H-tetrazol-5-yl) ethyl]-1H-benzotriazole (2) and appropriate acid chlorides. Compound 2 was synthesized by reacting 3-(1H-benzo[d][1,2,3]triazol-1-yl)propanonitrile (1) with sodium azide and ammonium chloride in the presence of dimethylformamide. The synthesized compounds were characterized by spectroscopic methods (IR, 1H NMR, mass spectroscopy) and elemental analysis. The titled compounds were evaluated for anti-nociceptive activity by the hot plate method and the writhing response method, and anti-inflammatory activity was evaluated by the carragenean induced paw edema method. 5-(2-(1H-benzo[d][1,2,3]triazo-1-yl)ethyl)-1H-tetrazol-1-yl)(4-aminophenyl)methanone (3d) and 5-(2-(1H-benzo[d][1,2,3]triazo-1-yl)ethyl)-1H-tetrazol-1-yl)(2-hydroxyphenyl)methanone (3g) exhibited significant anti-nociceptive activity. 1-(2-(1-Tosyl-1H-tetrazol-5-yl)ethyl)-1H-benzo[d][1,2,3]triazole (3c) and 4,5-(2-(1H-benzo[d][1,2,3]triazo-1-yl)ethyl)-1H-tetrazol-1-yl sulfonyl)benzenamine (3f) elicited superior anti-inflammatory activity compared to other synthesized compounds. Further investigations are needed to discern the mechanism of action.

Oxidation of Primary Aromatic Amines under Irradiation with Ultrasound and/or Microwaves

The oxidation of primary aromatic amines, p-methylaniline, p-ethylaniline and p-chloroaniline to the corresponding azo- and azoxy-compounds has been observed in ultrasound and/or microwaves systems. The individual irradiation of microwaves and its simultaneous irradiation with ultrasound obviously elevate the conversion of amines, as compared with the individual irradiation of ultrasound and the heating in a plain water bath. However, the formation of formamidine resulted in poor selectivity toward azo and azoxy products in the presence of dimethylformamide (DMF).

Zinc(0)/dimethylformamide-mediated synthesis of symmetrical carboxylic anhydrides from acid chlorides

The high yielding synthesis of symmetrical carboxylic anhydrides from acid chlorides mediated by zinc dust in the presence of dimethylformamide is presented. A mechanism involving the reductive insertion of zinc(0) into the C–Cl bond of a Vilsmeier-type iminium intermediate as the crucial step is also proposed.

Indole production by Pseudomonas stutzeri strain NAP-3 during anaerobic naphthalene biodegradation in the presence of dimethyl formamide

We previously reported on the denitrifier Pseudomonas stutzeri strain NAP-3 that degrades naphthalene without oxygen. In our present studies, naphthalene biodegradation by NAP-3 was slow or nearly absent when acetate was not present, suggesting a stimulating effect by the non-fermentable substrate. NAP-3 was sensitive to the amount of naphthalene in the culture; with naphthalene removal and nitrate utilization rates higher when present at 20 mg L− 1 compared to 40 mg L− 1. Electron equivalents represented by transformation of electron donor could be met assuming nitrate reduction to nitrite, except for the incubation with 40 mg L− 1 naphthalene which required complete denitrification. Transient production of the nitrogen-containing bicyclic indole was found by gas chromatograph mass spectrophotometry (GC/MS). Indole production was repeatable and affected by naphthalene concentration; with the 20 mg L− 1 culture producing the most indole. The production of indole was strictly biotic and required the presence of both naphthalene and the commonly-used solubilizing agent N, N dimethyl formamide (DMF). The source of nitrogen in indole was confirmed to be DMF through a series of growth experiments with NAP-3. No indole was produced in incubations fed naphthalene plus nitrate, nitrite or ammonia, either alone or in combination, when DMF was absent. Further, no production of indole was observed when heptamethyl nonane was used as an alternative solubilizing agent. We speculate that indole production proceeds through a pathway similar to the chorismic acid pathway for indole synthesis with incorporation of nitrogen from DMF. No other potential compounds of the chorismic pathway were found by GC/MS when naphthalene was the sole carbon source. NAP-3 grew statistically significantly on anthranilate, but not using salicylate or indole as the sole carbon source.

Synthesis of 5‐mono‐ and 5,7‐diamino‐pyrido[2,3‐d]‐pyrimidinediones with potential biological activity by regioselective amination

Abstractmagnified image5‐Alkyl‐/arylamino‐ and 5,7‐dialkyl/arylamino‐pyrido[2,3‐d]pyrimidine‐2,4‐diones (4,5, 7‐9) were prepared from the corresponding 5,7‐dichloro‐pyrido[2,3‐d]pyrimidine‐2,4‐diones 2 with aliphatic and aromatic amines 3 and 6 in a regioselective reaction. The 7‐monoazides 10, obtained by azidation of 5‐amino‐7‐chloro derivatives 4, were converted to iminophosphoranes by reaction with triphenyl‐phosphane via Staudinger reaction. Hydrolysis with aqueous acetic acid produced in one step 7‐unsubstituted‐amino‐pyrido[2,3‐d]pyrimidine‐2,4‐diones 12. In a similar amination reaction, 5‐chloropyrido[2,3‐d]pyrimidine‐2,4,7‐triones 13 were aminated and formylated to 5‐alkyl/arylamino‐6‐formyl derivatives 14‐16 in a combined one‐step‐reaction with bulky arylamines or alkylamines in the presence of dimethylformamide.

Synthesis of hydantoin and thiohydantoin related compounds from benzil and study of their cytotoxicity

Condensation of benzil (1) with urea, monophenyl urea and diphenyl urea in the presence of absolute ethanol using 30% aqueous NaOH gave the products 1a, 1b and 1c respectively and also with thiourea, monomethyl thiourea, dimethyl thiourea and diethyl thiourea the products 2a, 2b, 2c and 2d were obtained. Methylation of the product, 2a in the presence of dimethyl formamide (DMF) using K2CO3 formed 2. The compounds 1b, 1c, 2b, 2c and 2 showed highly cytotoxic activity and the compounds 1a, 2a, 2d showed relatively low cytotoxic activity against brine shrimp lethality bioassay.

Effect of herbicide tralkoxydim and 2-acylcyclohexane-1,3-diones on peroxidase activity

Effect of 2-acylcyclohexane-1,3-dione derivatives (tralkoxydim and its diketone precursors) on peroxidase-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), o-phenylenediamine (PDA), and the phenol-4-aminoantipyrine (4-AAP) couple has been studied. This effect varies from horseradish peroxidase (HRP) inactivation to activation in the reactions of peroxidation ofTMB, PDA, and, to a lesser extent, the phenol-4-AAP couple. The diketone-mediated HRP activation depends strongly on pH, presence of dimethylformamide, the structures of tralkoxydim and other diketones, and the substrate nature. The type of activation in the course of peroxidation with the presence of tralkoxydim can be noncompetitive (PDA and TMB) or mixed (TMB) depending on conditions. The maximal level of the HRP activation mediated by diketones depends on their structure. It can reach 4000% of the initial HRP-catalyzed peroxidation rate for TMB and ca. 1000% for PDA. A test system is proposed for quantitative tralkoxydim assay at millimolar concentration. It includes HRP and TMB as the substrate with spectrometrical monitoring of the TMB peroxidation product at 655 nm.

Oxokohlenstoffe und verwandte Verbindungen, 31 [1]. 3-Antipyryl-4-hydroxy-cyclobutendion (Antipyrylsemiquadratsäure) und seine Derivate / Oxocarbons and Related Compounds, 31 [1]. 3-Antipyryl-4-hydroxy-cyclobutenedione (Antipyrylsemisquaric Acid) and its Derivatives

Antipyrylsemisquaric chloride (9) has been prepared with excellent yield from antipyrylsemisquaric acid (8) and oxalic dichloride in the presence of dimethylformamide. Reaction of 9 with N and S nucleophiles afforded antipyrylsemisquaric acid derivatives, such as amides 12a - t, 14a - e, 15, hydrazides 18a - e, and thioesters 21a - i.

Synthesis of nucleosidic bonds using a nucleoside hydrolase in aqueous-organic media

The synthesis of inosine from nonactivated and nonprotected ribose and hypoxanthine was performed by enzyme-catalyzed condensation, using a nucleoside hydrolase from Crithidia fasciculata expressed in Escherichia coli with a synthetic gene. One round of directed evolution was performed in the presence of dimethylformamide, used to lower the water activity in the reaction media, leading to a double mutant (Asp54Asn, Arg137Gly). It afforded a doubling of the specificity constant for the hydrolysis of p-nitrophenol-β-d-riboside in the presence of 40% acetonitrile. In aqueous conditions, concentrations of 0.1 and 0.2 mM inosine were obtained, starting from 25 mM hypoxanthine and 2 or 3 M ribose, respectively. With 20% acetonitrile increases of 95% and 60% were observed. These conversions are very low, and the work exemplifies the difficulties encountered when trying to define conditions for hydrolase-catalyzed condensation and at the same time evolve an enzyme to perform well in these a priori unknown conditions.

Antibacterial, antifungal and anticonvulsant evaluation of novel newly synthesized 1-[2-(1H-tetrazol-5-yl)ethyl]-1H-benzo[d][1,2,3]triazoles

Several novel 1-[2-(1H-tetrazol-5-yl) ethyl]-1H-benzo[d][1,2,3]triazoles (3a-h) have been synthesized by the condensation of 1-[2-(1H-tetrazol-5-yl)-ethyl]-1H-benzotriazole (2) and appropriate acid chlorides. 1-[2-(1H-tetrazol-5-yl)-ethyl]-1H-benzotriazole (2) was synthesized by reacting 3-(1H-benzo[d][1,2,3]triazol-1-yl)propanenitrile with sodium azide and ammonium chloride in the presence of dimethylformamide. The synthesized compounds were characterized by IR and PMR analysis. The titled compounds were evaluated for their in-vitro antibacterial and antifungal activity by the cup plate method and anticonvulsant activity evaluated by the maximal electroshock induced convulsion method in mice. All synthesized compounds exhibited moderate antibacterial activity against Bacillus subtilis and moderate antifungal activity against Candida albicans. Compounds 5-(2-(1H-benzo[d][1,2,3]triazo-1-yl)ethyl)-1H-tetrazol-1-yl)(4-aminophenyl)methanone 3d and 5-(2-(1 H-benzo[d][1,2,3]triazo-1-yl)ethyl)-1H-tetrazol-1-yl)(2-aminophenyl)methanone 3e elicited excellent anticonvulsant activity.

Magnetic properties of trinuclear Ni–M–Ni complexes, M = Mn, Co and Ni

A tetradentate ligand, abbr. L 2− = dmSALPD 2− = N, N′-bis(salicylidene)-1,3-propanediaminato dianion, has been complexed with metal ions in the presence of dimethylformamide (dmf) and nitrite anion. As a result, trinuclear molecular complexes of the type [M II{Ni(NO 2)(L 2−)(dmf)} 2], where M II = Mn(II), Co(II) and Ni(II) were obtained. The magnetic susceptibility and magnetization data were treated simultaneously during the fitting procedure. In addition to the isotropic exchange, the zero-field splitting parameters D A were added to the spin Hamiltonian. An anti-ferromagnetic interaction was found in all complexes and the single ion magnetic anisotropy parameter for the Ni(II) peripheral centers adopt considerable values.

γ-Induced Graft Copolymerization onto Cellulosic Fabric Waste for Cationic Dye Removal

Radiation grafting of itaconic acid (IA) onto cellulosic fabric in the presence of dimethylformamide (DMF) as a solvent by the mutual method is discussed. Factors affecting the radiation graft copolymerization were investigated. These factors include the radiation dosage, the monomer concentration and the solvent. The grafted samples were characterized using FT-IR spectroscopy, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Utilization of the grafted cellulosic fabric waste in the removal of Methylene Blue (MB) from aqueous solution was examined. The adsorption data showed that the maximum adsorption capacity of Methylene Blue onto grafted cellulosic fabric waste was 38 mg/g. The adsorption data also obeyed the Langmuir and Freundlich isotherms.

Micropatterns of Ag2Se Nanocrystals

Silver selenide (Ag 2 Se) nanocrystals were synthesized solvothermally using a single source precursor silver selenite (Ag 2 SeO 3 ) in the presence of dimethyl formamide (DMF) in an autoclave. The effect of time and temperature on the crystalline and morphological behavior of the products was investigated. The interaction of Ag 2 SeO 3 with DMF resulted in the formation of Ag 2 Se nanoparticles, whereas mixed solvent of DMF and a few aliphatic alcohols (1:1 (v/v), at 165°C for 24 h) yielded novel microstructures. The mixed combination containing methanol-DMF yielded fractal-like morphology, while hollow needle-shaped structures resulted from a ethanol-DMF mixture. Rod shaped structures having riblike morphology were obtained from propanol-DMF mixed solvent.

Cathodic reactivity of graphite with carbon dioxide: an efficient formation of carboxylated carbon materials

Several kinds of graphites (natural from Ceylon, highly oriented pyrolytic (HOPG), pyrolytic crystals) were cathodically charged in the presence of dimethylformamide containing 0.1 M tetraalkylammonium tetrafluoroborate. After uptake of different amounts of charge, the reduced materials were allowed to react with carbon dioxide in solution. Data on the rate of carboxylation are given and the analytical methods providing information on the modification of graphite on the surface and in the bulk.

A Convenient Synthesis of 2,3‐Disubstituted Derivatives of 4H‐Pyrimido[2,1‐b]benzothiazole‐4‐one.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A CONVENIENT SYNTHESIS OF 2,3-DISUBSTITUTED DERIVATIVES OF 4H-PYRIMIDO[2,1-b]-BENZOTHIAZOLE-4-ONE

ABSTRACT 4H-Pyrimido[2,1-b ]benzothiazole-2-thiomethyl-3-cyano-4-one (3) has been prepared by the reaction of 2-amino benzothiazole (1) with ethyl-2-cyano-3,3-bismethyl thio acrylate (2) in the presence of dimethyl formamide and anhydrous potassium carbonate. Susceptibility of compound (3), towards condensation with different reagents like aryl amines, heteryl amines, phenols and compounds containing active methylene groups has been investigated.