Dimethylformamide In Presence Research Articles

Antimicrobial effects of new tetrahydrofurans

The increasing challenge of antimicrobial resistance (AMR) necessitates abrupt attention to discovering a new class of antimicrobials. In this study, we made efforts to prepare some fluoro-phenyl tetrahydrofurans-based DNA gyrase inhibitors as anti-microbial agents. To obtain the title compounds difluoro phenyl tetrahydrofurans (1-12), we used fluorophenyl-tetrahydrofuran and methyl benzenesulfonate to react with isoxazole derivatives and heterocyclic compounds bearing secondary amines in the presence of dimethylformamide (DMF) and sodium hydride (NaH) or potassium carbonate (K2CO3). The compounds were obtained in moderate to excellent yields and were characterized with FTIR, HRMS, NMR, etc. Among all compounds (1-12), compounds 1, 2, 11, and 12 were active against various Gram-positive and Gram-negative bacteria at a low concentration (MIC ranged between 1.25 and 9.75 μg/mL) and displayed low toxicity towards mammalian cells. We testified the in vitro DNA gyrase inhibitory potential for these compounds. A molecular docking study and an ADMET assessment study were carried out to understand the mode of interaction of ligand-DNA gyrase. In conclusion, we screened the compounds 1, 2, 11, and 12 for further clinical and pre-clinical studies.

Synthesis and Characterization of 2-Substituted Derivatives of 3-Cyano-2-Methylthio-4, 8-Dioxo-9H-Pyrimido[1,2-a]Pyrimidine

3-Cyano-2-methylthio-4,8-dioxo-9H-pyrimido[1,2-a]pyrimidine was reacted with various heterocyclic amines (nitrogen nucleophiles) such as pyrrolidine, piperidine, morpholine, piperazine, and differently substituted phenols (oxygen nucleophiles) in the presence of dimethyl formamide and potassium carbonate as a catalyst to afford the corresponding 2-substituted derivatives of the title compound. The structures of the products were confirmed through infrared, nuclear magnetic resonance, and mass spectral data.. KEYWORDS :Dimethyl formamide, Hetaryl amines, Oxygen nucleophiles, Potassium carbonate, Spectral data.

Unveiling a novel terpolymer-metal complex: A detailed exploration of synthesis, characterization, and its potential as an antimicrobial and antioxidant agent

In an innovative approach to push the boundaries of antimicrobial and antioxidant strategies, we present the synthesis and characterization of a novel terpolymer derived from N-Phenyl-p-phenylenediamine and 2-aminopyrimidine with formaldehyde in the presence of dimethylformamide as a reaction medium through polycondensation technique. Leveraging this terpolymer as a ligand, we introduce an intriguing terpolymer-metal complex, created with Ni (II) metal ion. In our pursuit to validate the structure and properties of these substances, we performed meticulous characterizations using important spectral studies such as FTIR, electronic, and 1H NMR spectroscopy. This provided us with a unique fingerprint for the (N-Phenyl-p-phenylenediamine-2-aminopyrimidine-formaldehyde) terpolymeric ligand (PAF) and its metal complex. In addition, the molecular weights of PAF terpolymer were established using gel permeation chromatography.Upon investigation, PAF terpolymer and PAF-Ni complex exhibited impressive antimicrobial activity, tested by the disc-diffusion technique. Both demonstrated potency against a range of harmful bacterial and fungal strains, including Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger. In an extension to their biological applications, we evaluated the free radical scavenging activity of PAF terpolymer and PAF-Ni complex using the DPPH assay. The complex PAF-Ni showcased an enhanced scavenging activity 73.94% (IC50 = 17.58) compared to the ligand PAF 63.06% (IC50 = 27.61) at 100 μg/ml indicating its potential role in oxidative stress management.

Synthesis, crystal structure, computational studies, and antioxidant properties of dimethylformamide-bound magnesium tetraphenylporphyrin

The synthesis, characterization and crystal structure of a dimethylformamide (DMF) coordinated magnesium tetraphenylporphyrin, [Mg(TPP)(DMF)]·CH2Cl2 (1), is described. Theoretical studies including optimization of the geometry, simulation of the electronic spectrum and binding energy calculations were performed for the complexes using the DFT method to understand the axial coordination in magnesium porphyrins. To get insight into intermolecular interactions Hirshfeld surface analyses and plotting of the 2D fingerprint was performed. Antioxidant activity was measured for the complex which showed enhanced antioxidant activity in the presence of DMF.

Synthesis and some transformations of new acetophenones with carbamate function

Acylation of methyl- N -phenyl-, 2-(morpholin-4-yl)ethylphenyl-, 2-(pyridin-2-yl)ethylphenyl-carbamates with acetic anhydride in polyphosphoric acid at 50-55°C for 3 h proceeds in the para -position to the carbamate grouping to form the corresponding acetophenones. Acylation under similar conditions of methyl 2-(methoxyphenyl)carbamate occurs in the para -position to the methoxy group with the formation of methyl N -(5-acetyl-2-methoxyphenyl)carbamate. The interaction of para - and ortho -acetyl-substituted methyl- N -phenylcarbamate with N -bromosuccinimide, copper(II) acetate in the presence of dimethylformamide at 80°C and with chloro- and hydrobromic acids in the presence of DMSO in ethyl acetate at 30-33°C yielded methyl {4(2)-[(dimethylamino)(oxo)-acetyl]phenyl}- and N -[4(2)-(2-bromo-2-chloroacetyl)phenyl]-carbamates. Condensation of 2-morpholinoethyl [(pyridin-2-yl)ethyl] N -(4-acetylphenyl)carbamates with 4-methoxybenzaldehyde in the presence of a methanolic KOH solution gave the corresponding chalcones.

Going Up the Ladder: Stacking Four 4,4'-Bipyridine Moieties within a Ti(IV)-Based Tetranuclear Architecture.

Biphenol-based ligands have proven their ability to bind titanium(IV) centers and generate sophisticated self-assembled structures in which auxiliary nitrogen ligands often complete the coordination sphere of the metal and improve stability. Here, a central 4,4'-bipyridine, which acts as both a spacer and a source of monodentate nitrogen to complete the coordination sphere of the Ti(IV) complex, was incorporated within two bis-2,2'-biphenol strands, 3H4 and 4H4. Both proligands possess structural features that are well adapted to form self-assembled structures built from titanium-oxygen-nitrogen units; however, their different degrees of torsional freedom strongly influenced the nuclearity of the complexes formed. The presence of a phenyl spacer between the bipyridine and the biphenol moieties of 3H4 provided enough flexibility for the ligand to wrap around one titanium(IV) center to form a mononuclear complex Ti(3)(DMF)2 in the presence of dimethylformamide (DMF). Assembly of the more rigid ligand 4H4 with Ti(OiPr)4 afforded a tetranuclear complex Ti4(4)2(4H)2(OEt)2 containing four stacked 4,4'-bipyridine units as shown by the X-ray structure of the complex. Density functional theory studies suggested that the assembly of this tetrametallic complex involves a dimetallic intermediate with TiO6 nodes that is converted to the thermodynamically stable tetranuclear complex with two TiO6 nodes and two TiO5N units with enhanced covalent character.

Reductive Amination Revisited: Reduction of Aldimines with Trichlorosilane Catalyzed by Dimethylformamide─Functional Group Tolerance, Scope, and Limitations.

Aldimines, generated in situ from aliphatic, aromatic, and heteroaromatic aldehydes and aliphatic, aromatic, and heteroaromatic primary or secondary amines, can be reduced with trichlorosilane in the presence of dimethylformamide (DMF) as an organocatalyst (≤10 mol %) in toluene or CH2Cl2 at room temperature. The reduction tolerates ketone carbonyls, esters, amides, nitriles, sulfones, sulfonamides, NO2, SF5, and CF3 groups, boronic esters, azides, phosphine oxides, C═C and C≡C bonds, and ferrocenyl nucleus, but sulfoxides and N-oxides are reduced. α,β-Unsaturated aldimines undergo 1,2-reduction only, leaving the C═C bond intact. N-Monoalkylation of primary amines is attained with a 1:1 aldehyde to amine ratio, whereas excess of the aldehyde (≥2:1) allows second alkylation, giving rise to tertiary amines. Reductive N-alkylation of α-amino acids proceeds without racemization; the resulting products, containing a C≡C bond or N3 group, are suitable for click chemistry. This reaction thus offers advantages over the traditional methods (borohydride reduction or catalytic hydrogenation) in terms of efficiency and chemoselectivity. Solubility of some of the reacting partners appears to be the only limitation. The byproducts generated by the workup with aqueous NaHCO3 (i.e., NaCl and silica) are environmentally benign. As a greener alternative, DMA can be employed as a catalyst instead of DMF.

Controllable Activation of β-Alkyl Nitroalkenes: Regioselective Synthesis of Allyl and Vinyl Sulfones.

The regiospecific radical reactions of β-alkyl nitroalkenes with sulfonyl hydrazides depended to a great extent on the choice of a solvent and catalyst. In the presence of dimethylformamide (DMF), β-alkyl nitroalkenes more likely converted into electron-rich allyl nitro compounds, which reacted with sulfonyl hydrazides to afford allyl sulfones with high regioselectivity. While in acetonitrile (CH3CN), vinyl sulfones were obtained directly via sulfonation of electron-deficient β-alkyl nitroalkenes. The mechanism investigation revealed that the regioselectivity was controlled by the equilibrium of β-alkyl nitroalkenes and allyl nitro compounds.

Synthesis of Micro-Mesoporous ZSM-23 Zeolite

Two procedures were suggested for preparing a micro-mesoporous zeolite of MTT topology (ZSM-23 type) with the molar ratio SiO2/Al2O3 = 100 in the presence of dimethylformamide as a template. The first procedure involves hydrothermal crystallization under the conditions ensuring the formation of nanosized crystals. The second procedure is postsynthetic treatment of the zeolite with a NaOH solution to increase the mesopore volume. Samples of ZSM-23 zeolites with the crystal size of 100–200 nm with improved textural characteristics (micropore volume up to 0.1 cm3 g–1, mesopore volume up to 0.70 cm3 g–1) were obtained in >85% yield based on the silica used. The acid characteristics of the synthesized samples are similar to those of the zeolites prepared using pyrrolidine, which is expensive and is not produced in Russia.

Thermal degradation investigations of newly synthesized terpolymeric polychelates

A novel terpolymer p-phenylenediamine-thiosemicarbazide-formaldehyde (PTSF) has been synthesized by polycondensation of p-phenylenediamine and thiosemicarbazide with formaldehyde in the presence of dimethylformamide as a catalyst at 130 °C with 1:1:2 mol proportion of reacting monomers. The terpolymer metal complexes were prepared with Ni2+, Cu2+ and Zn2+ metal ions using PTSF terpolymer as a ligand. The structure of newly synthesized terpolymer and its metal complexes have been elucidated and confirmed on the basis of elemental analysis and various spectral techniques, namely FT-IR, UV–visible and NMR (1H and 13C) spectroscopy. Averages of the molecular weight of the terpolymer were measured by gel permeation chromatography. Surface features of the terpolymer and its metal complexes were investigated by scanning electron microscopy. The thermal decomposition pattern and the kinetics of thermal decomposition of the terpolymer and its metal complexes were measured by thermogravimetric analysis. Kinetic and thermodynamic parameters such as activation energy (Ea), order of reaction (n), frequency factor (Z), entropy change (ΔS), free energy change (ΔF) and apparent entropy (S*) were calculated using Freeman-Carroll and Sharp-Wentworth methods. Thermogravimetric was used to analyze the order of thermal stabilities of the terpolymer ligand and its metal complexes.

Crystal structures of 2-amino-2-oxoethyl 4-bromo-benzoate, 2-amino-2-oxoethyl 4-nitro-benzoate and 2-amino-2-oxoethyl 4-amino-benzoate monohydrate.

The title mol-ecules were synthesized by the reaction of 4-substituted sodium benzoates with chloro-acetic acid amide in the presence of di-methyl-formamide. The yields of 2-amino-2-oxoethyl 4-bromo-benzoate, C9H8BrNO3, I, 2-amino-2-oxoethyl 4-nitro-benzoate, C9H8N2O5, II, and 2-amino-2-oxoethyl 4-amino-benzoate monohydrate, C9H10N2O3·H2O, III, are 86, 78 and 88%, respectively. The low yield of II is explained by the reduced reactivity of the mol-ecule in a nucleophilic exchange reaction because of the negative induction and negative mesomeric effects of the nitro group on the benzene ring. Single crystals were obtained from the products under the same (temperature and solvent) conditions. In the case of III, the crystals formed as a monohydrate. In all three crystal structures, the same type of inter-molecular N-H⋯O hydrogen bonds are observed, but the mol-ecules differ in some torsion angles as well as in the dihedral angles between the mean planes of the benzene rings and the amide groups.

Ultrasound Aided Expedient Synthesis, Characterization and Antimicrobial Studies of Fluorenyl-Hydrazono-Thiazole Derivatives

Ultrasound assisted facile synthesis of fluorenyl-hydrazonothiazoles (4a-d) in quantitative yields by the condensation of 2-(9H-fluoren-9-ylidene)hydrazinecarbothioamide (2) with substituted phenacyl bromides in presence of dimethyl formamide has been reported. The reaction of carbothioamide 2 with α-haloacids resulted in to fluorenyl-hydrazonothiazolidin-4-ones (3). The structural characterization of the cyclized products have been established by elemental analysis and spectral data (IR, NMR and mass). The antimicrobial studies of the synthesized compounds are also reported.

Catalytic conversion of CO2 to propylene carbonate over Pt-decorated Mg-substituted metal organic framework

Porous coordination polymers of Mg (II) dihyroxyterephtalate (Mg-MOF-74) at various Ptx loadings (x = 0–10 wt%) were synthesized, characterized and tested for the catalytic cycloaddition reaction between CO2 and propylene oxide (PO). The reaction was studied over a range of temperatures between (100–170 °C), pressures (9.1–19.5 bar) and reaction times (4–15 hours) to produce propylene carbonate (PC). The results show that the Pt loading on the catalyst surface improves the selectivity toward PC in the presence of dimethylformamide (DMF) and dichloromethane (DCM) which serve as solvents and promoters for the reaction. Pt loading is shown to be concomitantly related to the number of uncoordinated MgO defect sites produced during synthesis. As Pt loading increases, the number of uncoordinated MgO sites in the Mg-MOF-74 framework structure also increases. During reaction, PO conversion and PC selectivity were shown to systematically increase with Pt loading and the number of uncoordinated MgO defect sites. A synergistic effect is observed where the combined use of Ptx/Mg-MOF-74, DMF and DCM exhibit performance benefits beyond their use individually. The catalysts we characterized before and after reaction using XRD, EDX, ICP, BET, SEM and TGA. The catalysts show a relatively high stability and reusability as confirmed by reaction studies, XRD and FE-SEM.

Gram-scale economical synthesis of trans-coniferyl alcohol and its corresponding thiol

AbstractConiferyl alcohol is considered to be a potent antioxidant and a precursor of several bioactive products. In addition, it is a frequently used as a model compound in lignin chemistry. Coniferyl thiol is used analogously to study the sulfur chemistry in technical lignins. Coniferyl alcohol was synthesized in a large scale from commercially available ferulic acid by a mixed anhydride reduction method which affords high yields (84%) under very mild conditions and allows using sodium borohydride. The nucleophilic substitution of 4-O-acetylated coniferyl alcohol (3) with thioacetic acid in the presence of dimethylformamide (DMF) dineopentylacetal afforded 4-O-acetylated coniferyl thioacetate (5) in a 70% yield, which, in a 72% yield, was deprotected to the respective thiol (6). Both coniferyl alcohol and coniferyl thiol were comprehensively analytically characterized [one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy]. The presented approach renders the two model substances readily available on a gram scale and according to low-risk, environmentally compatible protocols.

Solvothermal synthesis of porous organic cage CC3 in the presence of dimethylformamide as solvent

Morphology, and crystal product of porous organic cage CC3, was modified by the use of a novel and non-traditional high dielectric constant solvent dimethyl formamide.

Field-induced slow relaxation of magnetization in the S = 3/2 octahedral complexes trans-[Co{(OPPh2)(EPPh2)N}2(dmf)2], E = S, Se: effects of Co–Se vs. Co–S coordination

Magnetometry studies on octahedral trans-[Co{(OPPh2)(EPPh2)N}2(dmf)2], E = S, Se, complexes.

Olefin Epoxidation over Metal-Organic Frameworks Modified with Transition Metals

Mixed aluminum-containing metal-organic frameworks (MOF) modified with Fe, V, and Ti are synthesized in two steps. At the first step, the amorphous precursors of metal-organic frameworks containing various amounts of transition metals are obtained by the electrochemical method. At the second step, the precursors are crystallized under solvothermal conditions. Study of the effect of synthesis conditions shows that Fe-containing metal-organic frameworks crystallize in the presence of dimethylformamide; V- and Ti-containing counterparts crystallize in the presence of water. The time and temperature of crystallization are varied in the range from 150 to 200°С and 24 to 72 h depending on the concentration of the transition metals. The resulting samples are investigated by low-temperature nitrogen adsorption, scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and thermogravimetric and differential thermal analysis (TGA-DTA). Research into the influence of catalyst composition on its activity in 1-octene epoxidation by tert-butyl hydroperoxide suggests that that the titanium-containing samples are catalytically inactive, while the vanadium-containing samples are more active than the iron-containing ones. Testing of the vanadium-containing samples in propylene epoxidation demonstrates that their activity is comparable with the activity of a commercial titanium silicate catalyst.

Improve Salinivibrio zinc-metalloprotease function in less polar organic solvents by increasing surface hydrophobicity

Organic solvents tend to strip water from protein and thereby disrupt non-covalent forces and decrease enzyme activity and stability. In the present study, we have replaced the surface charge residues in Salinivibrio zinc-metalloprotease (SVP) with hydrophobic ones (E12V, D22I, D24A and D310I) in order to study the effects of surface hydrophobicity with hydrophobic strength of organic solvents. Compared to SVP, D24A exhibited an increase in kcat and catalytic efficiency and a reduction in thermal inactivation rate in aqueous solvent. Structural studies indicated that the replacement of surface charge residues with hydrophobic residues would not induce conformational changes. C50 value (the value of solvent concentration where 50% of enzyme activity remains), ki (irreversible thermoinactivation rate), and kinetic parameters of E12V, D22I, and D24A were higher in isopropanol and n-propanol. D24A is found to be the most efficient mutant for its remarkable decrease in ki value in the presence of isopropanol and n-propanol and a reduction in ki value in the presence of dimethylformamide (DMF) and methanol. C50 value in this variant was increased about 1.2% in DMF, 2% in methanol and isopropanol and 2.5% in n-propanol. Results revealed that, there was a correlation between surface hydrophobicity of SVP and hydrophobic strength of organic solvents.

Solvothermal conversion of coal into nitrogen-doped carbon dots with singlet oxygen generation and high quantum yield

Fluorescent nitrogen-doped carbon dots (N-CDs) are synthesized by a facile one-pot solvothermal approach from Taixi anthracite in the presence of dimethyl formamide (DMF). Benefiting from superior dispersion of light components in DMF and easy exfoliation of smaller sp2-carbon structures from the anthracite, the as-prepared N-CDs show a strong photoluminescence (PL) with a high quantum yield (QY) of 47.0% and production yield of 25.6wt%. Besides, the N-CDs also exhibit a singlet oxygen (1O2) generation behavior with a 1O2 generation QY of 19.0%. Moreover, the as-obtained N-CDs emit blue PL under the excitation wavelength of 365nm, and can be easily dispersed in polymethyl methacrylate (PMMA), retaining the inherent advantages of the N-CDs and the PMMA matrix. The possible mechanism involved in the formation of N-CDs is proposed and discussed in terms of the macromolecular structure of the anthracite and the solvothermal approach adopted in the study.

Adhesion between silica surfaces due to hydrogen bonding

The adhesion between surfaces can be enhanced significantly by the presence of hydrogen bonding. Confined water at the nanoscale can display behaviour remarkably different to bulk water due to the formation of hydrogen bonds between two surfaces. In this work we investigate the role of confined water on the interaction between hydrophilic surfaces, specifically the effect of organic contaminants in the aqueous phase, by measuring the peak adhesive force and the work of adhesion. Atomic force microscope cantilevers presenting hemispherical silica tips were interacted with planar single crystals of silica in the presence of dimethylformamide, ethanol, and formamide; solution compositions in the range 0–100 mol% water were investigated for each molecule. Each molecule was chosen for its ability to hydrogen bond with water molecules, with increasing concentrations likely to disrupt the structure of surface-bound water layers. With the exception of aqueous solutions containing low concentrations of ethanol, all molecules decreased the ability of confined water to enhance the adhesion between the silica surfaces in excess of the predicted theoretical adhesion due to van der Waals forces. The conclusion was that adhesion depends strongly on the formation of a hydrogen-bonding network within the water layers confined between the silica surfaces.