N-ethylformamide Research Articles

Dissociative electron attachment to amide bond containing molecules: N-ethylformamide and N-ethylacetamide.

To advance our quest to understand the role of low energy electrons in biomolecular systems, we performed investigations on dissociative electron attachment (DEA) to gas-phase N-ethylformamide (NEF) and N-ethylacetamide (NEA) molecules. Both molecules contain the amide bond, which is the linkage between two consecutive amino acid residues in proteins. Thus, their electron-induced dissociation can imitate the resonant behavior of the DEA process in more complex biostructures. Our experimental results indicate that in these two molecules, the dissociation of the amide bond results in a double resonant structure with peaks at ∼5 eV and 9 eV. We also determined the energy position of resonant states for several negative ions, i.e., the other dissociation products from NEF and NEA. Our predictions of dissociation channels were supported by density functional theory calculations of the corresponding threshold energies. Our results and those previously reported for small amides and peptides imply the fundamental nature for breakage of the amide bond through the DEA process.

Quorum Sensing Inhibition in Chromobacterium violaceum, Antibacterial Activity and GC-MS Analysis of Centaurea praecox (Oliv. & Hiern) Extracts

The quorum sensing (QS) mechanism has become a viable research strategy for the discovery of plant-derived anti-virulent agents to control drug-resistant bacteria. The increasing incidences of drug-resistant bacteria and the effort to curb it necessitate this study. We investigated the QS inhibitory potential of Centaurea praecox extracts on Chromobacterium violaceum (CV), antibacterial activity, and determination of chemical composition using GC-MS. C. praecox was subjected to sequential extraction using hexane (HEX), dichloromethane (DCM), ethyl acetate (EA), ethanol (ET), and aqueous (AQ) solvents. The extracts were subsequently evaluated for antibacterial activity using disc diffusion and QS violacein inhibition using spectrophotometry. The antibacterial effects of the extracts were moderate on gram-positive bacteria at 4 mg/mL in the order: HEX >EA >DCM >ET =AQ. However, the DCM extract demonstrated the most effective violacein inhibition of ≥80% at 0.3 mg/mL. QS violacein inhibitions were generally found to be concentration-dependent in the order: DCM >EA >HEX >ET =AQ with efficacies of ≥ 90% inhibition at ≥ 0.6 mg/mL. GC-MS analysis on the most potent DCM extract revealed N-vinylmethanimine, N-ethyl formamide, and propanamide among components identified. We concluded that C. praecox DCM extract contains bioactive chemicals as QS inhibitors and potential anti-virulent agents capable of combating the pathogenicity of drug-resistant bacteria in vivo.

Investigation of the surface interactions of selected amides with mesoporous silica using FTIR spectroscopy and hyperspectral imaging

The adsorption of eight structurally different secondary and tertiary amides (N-ethyl formamide, N-methyl-propionamide, N-cyclohexyl formamide, N-tert-Butyl-formamide, N-Methyl-benzamide, N-Pentyl-benzamide, N,N-dimethyl acetamide and N,N-diethyl dodecanamide) from carbon tetrachloride solution on mesoporous silica (MS) material was investigated by kinetic FTIR spectroscopic measurements. Of the tested amides, N-methyl-propionamide showed the highest affinity for the MS material. The results indicate that tertiary amides show low affinity for the surface interaction with MS while the affinity of secondary amides decreases with the increase in the volumeof substituents. This result is correlated to the capability of amide N-H to participate in hydrogen bonding with the MS surface. Results of FTIR spectroscopy evidence the presence of amides adsorbed on the surface of MS while the analysis of hyperspectral images reveals the possibility of constructing effective qualitative hyperspectral sensors for amides based on MS as a sensing substrate.

Volumetric Properties of (Difurylmethane + an Amide) Binary Mixtures at 293.15K, 298.15K and 303.15 K

Densities (&rho;) of pure difuryl methane (DFM), N-methylformamide (NMF), N-ethylformamide (NEF), N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) and those of [DFM + (NMF or NEF or DMF or DMA] binary mixtures over the entire composition range, have been measured at (<i>T</i> = 293.15, 298.15 and 303.15) K and atmospheric pressure. Excess molar volumes (<img width="18" height="16" src="http://article.sciencepublishinggroup.com/journal/128/1281027/image001.png" />), of each binary system were calculated and correlated by the Redlich-Kister equation. <img width="18" height="16" src="http://article.sciencepublishinggroup.com/journal/128/1281027/image001.png" /> values for each binary system were negative at each of the three temperatures investigated (<i>T</i> = 293.15, 298.15 and 303.15) K. The <img width="18" height="16" src="http://article.sciencepublishinggroup.com/journal/128/1281027/image001.png" /> values decreased with temperature increase for each of the binary systems investigated. Sign and magnitude of <img width="18" height="16" src="http://article.sciencepublishinggroup.com/journal/128/1281027/image001.png" /> are discussed in-terms of type and nature of intermolecular interactions that occur in a binary mixture. The <img width="18" height="16" src="http://article.sciencepublishinggroup.com/journal/128/1281027/image001.png" /> data have been used to derive excess partial molar volumes (<img width="18" height="16" src="http://article.sciencepublishinggroup.com/journal/128/1281027/image002.png" />), limiting excess partial molar volumes (<img width="32" height="16" src="http://article.sciencepublishinggroup.com/journal/128/1281027/image003.png" />) and limiting partial molar volumes at infinite dilute region (<img width="20" height="16" src="http://article.sciencepublishinggroup.com/journal/128/1281027/image004.png" />) of each component of the binary mixture. Results are discussed in terms of possible intermolecular interactions and structural effects that occur in the binary mixtures.

N-ethylformamide dimer. A β-turn model peptide in the gas phase

Reported here are CP-FTMW experiments on N-ethylformamide (NEF), previously studied by pure rotational spectroscopy in the gas phase by Hirota and co-workers (2005). Two conformers of the monomer (trans sc and cis ac), the trans-trans sc dimer, and several NEF-water complexes have been detected. (Only trans sc was observed in the earlier experiments.) Of these species, the trans-trans sc dimer is the most interesting since its three-dimensional structure bears a striking resemblance to β-turns in folded peptides. The well-known anti-parallel β-sheet structures would be expected to have near-zero dipole moments and are therefore discriminated against by the CP-FTMW method.

Volumetric Properties of Binary Mixtures of 1-Butyl-1-Methylpyrrolidinium Tris(pentafluoroethyl)trifluorophosphate with N-Methylformamide, N-Ethylformamide, N,N-Dimethylformamide, N,N-Dibutylformamide, and N,N-Dimethylacetamide from (293.15 to 323.15) K

Experimental densities of binary mixtures of ionic liquid 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate ([BMPYR][FAP]) with two protic amides—N-methylformamide (NMF) and N-ethylformamide (NEF)—and three aprotic—N,N-dimethylformamide (DMF), N,N-dibutylformamide (DBF), and N,N-dimethylacetamide (DMA)—are reported in the temperature range from (293.15 to 323.15) K and at atmospheric pressure (0.1 MPa) over the whole composition range. This ionic liquid was selected due to its hydrophobic properties and hydrolytic stability. The excess molar volumes derived from the experimental densities appear to be positive for all of the studied mixtures in the whole composition range at all temperatures. The systems with aprotic amides (DMF, DBF, DMA) show higher values of excess molar volume compared to those with protic amides (NMF, NEF), while the number of the methyl groups at the carbon atom does not affect the composition corresponding to the maximum of the excess molar volume.

Densitometric and spectroscopic investigation of interactions of selected N-substituted amides and acetonitrile

The paper reports the results of densitometric and FTIR spectroscopic study of the interactions of N-methylformamide, N-ethylformamide and N-ethylacetamide with acetonitrile. Excess molar volumes, VmE, of N-methylformamide (NMF)+acetonitrile, N-ethylformamide (NEF)+acetonitrile, N-ethylacetamide (NEA)+acetonitrile have been determined at the temperatures: 298.15K, 303.15K, 308.15. Excess molar volumes were fitted with Redlich–Kister equation. The spectroscopic characteristics for NH⋯N hydrogen bonded complex and equilibrium constant for 1:1 complex formation, at 25°C were determined by using IR measurements. The results have been discussed in terms of hydrogen bonding. Spectroscopic results confirm the assumptions related to the volume contractions of examined binary mixtures.

Volumetric Properties of Binary Mixtures of N-Ethylformamide with Tetrahydropyran, 2-Pentanone, and Propylacetate from (293.15 to 313.15) K

Densities of binary liquid mixtures of N-ethylformamide (NEF) with tetrahydropyran (THP), 2-pentanone (P), and propylacetate (PA) were measured at temperatures from (293.15 to 313.15) K and at atmospheric pressure over the whole composition range. Excess molar volumes, VE, have been calculated from the experimental densities and were fitted to the Redlich–Kister polynomial equation. Investigated binary systems show negative excess molar volumes over the entire composition and temperature ranges. For all studied binary mixtures VE values become more negative as the temperature increases. Other volumetric properties, such as thermal expansion coefficients, partial molar volumes, apparent molar volumes, and partial molar excess volumes, have been calculated, too.

Volumetric properties of binary mixtures of N-ethylformamide with tetrahydrofuran, 2-butanone, and ethylacetate from T = (293.15 to 313.15) K

Densities of binary liquid mixtures of N-ethylformamide (NEF) with tetrahydrofuran (THF), 2-butanone (B), and ethylacetate (EA) were measured at temperatures from (293.15 to 313.15)K and at atmospheric pressure over the whole composition range. Excess molar volumes, VE, have been obtained from values of the experimental density and were fitted to the Redlich–Kister polynomial equation. The VE values for all three mixtures are negative over the entire composition and temperature ranges. The VE values become more negative as the temperature increases for all binary mixtures studied. Other volumetric properties, such as isobaric thermal expansion coefficients, partial molar volumes, apparent molar volumes, partial molar excess volumes and excess thermal expansions have been calculated.

ChemInform Abstract: Catalytic Cooperation Between MoO3 and Sb2O4 in N-Ethyl Formamide Dehydration. Part 3. Comparison of a Mathematical Model Based on the Remote Control Mechanism with Experimental Results.

ChemInform Abstract: Catalytic Cooperation Between MoO3 and Sb2O4 in N-Ethyl Formamide Dehydration. Part 3. Comparison of a Mathematical Model Based on the Remote Control Mechanism with Experimental Results.

ChemInform Abstract: Catalytic Cooperation Between MoO3 and Sb2O4 in N-Ethyl Formamide Dehydration. Part 2. Nature of Active Sites and Role of Spillover Oxygen.

ChemInform Abstract: Catalytic Cooperation Between MoO3 and Sb2O4 in N-Ethyl Formamide Dehydration. Part 2. Nature of Active Sites and Role of Spillover Oxygen.

17O NMR Studies of the Solvation State of cis/trans Isomers of Amides and Model Protected Peptides

17O shielding constants have been utilized to investigate solvation differences of the cis/trans isomers ofN-methylformamide (NMF),N-ethylformamide (NEF), andtert-butylformamide (TBF) in a variety of solvents with particular emphasis on aqueous solution. Comparisons are also made with protected peptides of the formulas CH3CO–YOH, CH3CO–Y–NHR (Y = Pro, Sar), and CH3CO–Y–Z–NHR (Y = Pro; Z =D-Ala) selectively enriched in17O at the acetyl oxygen atom. Hydration at the amide oxygen induces large and specific modifications of the17O shielding constants, which are practically the same for the cis and trans isomers of NMF, NEF, and the protected peptides. Fortert-butylformamide, the strong deshielding of the trans isomer compared to that of the cis isomer may be attributed to an out-of-plane (torsion-angle) deformation of the amide bond and/or a significant reduction of solvation of the trans isomer due to steric inhibition of the bulkytert-butyl group. Good linear correlation between δ(17O) of amides and δ(17O) of acetone was found for different solvents which have varying dielectric constants and solvation abilities. Sum-over-states calculations, within the solvaton model, underestimate effects of the dielectric constant of the medium on17O shielding, while finite-perturbation-theory calculations give good agreement with the experiment.

ChemInform Abstract: Catalytic Cooperation Between MoO3 and Sb2O4 in N‐Ethyl Formamide Dehydration. Part 1. Preparation, Characterization, and Catalytic Results.

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Catalytic cooperation between MoO 3 and Sb 2O 4 in N-ethyl formamide dehydration I. Preparation, characterization, and catalytic results

Catalysts containing MoO 3 and α-Sb 2O 4 with different “architectures” were prepared by different methods: mixing of separately prepared pure oxides, impregnation of MoO 3 by Sb 2O 4 or vice versa. We report results obtained in the oxygen-aided dehydration of N-ethyl formamide catalyzed by these solids. A strong synergy between Mo and Sb is always observed. Extensive characterization of the catalysts before and after catalytic test, by X-ray diffraction, Electron Microscopy, Analytical Electron Microscope, XPS, and Ion Scattering Spectroscopy excludes the formation of mixed oxides or solid solutions as well as mutual contamination. Rather, the artificial contamination created by impregnation with a precursor of the other oxide exhibits a strong tendency to disappear. The catalytic synergy persists after the contamination has disappeared. The origin of the observed synergy is attributed to a remote control mechanism, namely spillover oxygen produced by α-Sb 2O 4 creates and/or regenerates active and selective sites on MoO 3.

Catalytic cooperation between MoO 3 and Sb 2O 4 in N-ethyl formamide dehydration III. Comparison of a mathematical model based on the remote control mechanism with experimental results

We present a mathematical model of the remote control effect in the cooperation between α-Sb 2O 4 (spillover oxygen donor) and MoO 3 (acceptor and catalytic phase) in the oxygen assisted dehydration of formamides. The model is compared with experimental results obtained with 21 mechanical mixtures of α-Sb 2O 4 and MoO 3 of different compositions, at 3 different reaction temperatures, and oxygen partial pressure varying over a range of more than 2 orders of magnitude. The observed increase of activity of MoO 3 due to the effect of the remote control corresponds extremely well (variance of squared residue better than 3 × 10 −3) to the results of the mathematical model. We have verified that the magnitude of the kinetic parameters and surface concentration of spillover oxygen is physically acceptable, and that the variations of these parameters with the temperature correspond to those predicted by the general laws of physical chemistry.

Catalytic cooperation between MoO 3 and Sb 2O 4 in N-ethyl formamide dehydration II. Nature of active sites and role of spillover oxygen

The present work reports experiments designed to further investigate the role of MoO 3 and Sb 2O 4 in the cooperative effect they exhibit in N-ethyl formamide dehydration. Temperature-programmed desorption of NH 3 showed that Bronsted acid sites are responsible for activity. TPD of CO 2 gave no indication of basic sites. The Brønsted sites are sensitive to reduction and reoxidation. Thermoreoxidation of previously reduced molybdenum oxide and oxidation of carbon deposited on MoO 3 are more rapid when α-Sb 2O 4 is admixed. The interpretation of the phenomenon is that α-Sb 2O 4 dissociates molecular O 2 to an oxygen spillover species which can maintain MoO 3 at a high degree of oxidation and, if necessary, reoxidize it or remove deposited carbon. Brønsted sites necessitate a high degree of oxidation and their number is consequently promoted by spillover oxygen. Mechanisms are proposed for the dissociation of oxygen, the reoxidation of pre-reduced MoO 3, and the formation of Brønsted acid sites. The importance of the reported results for selective oxidation or multicomponent catalysts is discussed.

Studies on the V2O5–TiO2system. Part 1.—TiO2(rutile)–V2O5

Mechanical mixtures of separately prepared V2O5 and TiO2(rutile) have been used as catalysts in the dehydration of N-ethylformamide (NEF) in the presence of oxygen. Catalytic activity has been measured as a function of the gas hourly space velocity (GHSV), the molar ratio of oxygen to NEF (O/N) and the composition of the catalysts. The characterization of fresh and used catalysts has been carried out using different physicochemical techniques: B.E.T. surface area analysis, XRD, XPS. It has been established that there exists a synergetic effect between rutile and V2O5 thus explaining the catalytic properties of their mechanical mixtures. V2O5 is dispersed over the surface of rutile grains in the course of the catalytic reaction. A simultaneous process of reduction and reoxidation of V2O5 takes place. The type of reduced vanadium oxide formed depends on the O/N ratio and GHSV. The deeply reduced and fully oxidized vanadium oxides are very active but are not selective. Medium reduced vanadium oxides are less active but give higher propiononitrile yields (the selective product). It was concluded that rutile disadvantages the stabilization of vanadium in a high oxidation state. It shifts the redox steady-state equilibrium of the vanadium phase towards the more reduced vanadium oxides.

Studies on the V2O5–TiO2system. Part 2.—TiO2(anatase)–V2O5

Mechanical mixtures of separately prepared V2O5, V6O13 and anatase have been used as catalysts in the dehydration of N-ethylformamide (NEF) in the presence of oxygen. Catalytic activity was measured as a function of the gas hourly space velocity (GHSV), the oxygen-to-N-ethylformamide ratio (O/N), the temperature, the V2O5 and V6O13 contents and the surface area of V2O5. The characterization was carried out using B.E.T. surface analysis, XRD and XPS techniques.It was concluded that there exists a cooperation between V2O5 and anatase, which brings about the stabilization of V6O13 by the anatase. V6O13 is the most selective phase in NEF dehydration. The calcination of V2O5–anatase mechanical mixtures results in (i) an increase of the V2O5 dispersion over the anatase surface, which brings about an increase of the selective product (propiononitrile), and (ii) partial anatase-into-rutile transformation, resulting in a decay of the catalytic properties. Under appropriate reaction conditions (temperature, O/N ratio) the anatase-into-rutile transformation does not take place.

Cytotoxicity and metabolism of the hepatotoxin N-methylformamide and related formamides in mouse hepatocytes

Some N-alkylformamides such as N-methylformamide (NMF) possess hepatotoxic properties in vivo. To study the mechanism of this toxicity, suspensions of mouse hepatocytes were tested as an in vitro model system suitable for the study of the relationship between (i) the toxic potential of formamides, (ii) their metabolism to N-alkylcarbamoylating species, and (iii) their ability to deplete hepatic glutathione pools. The effects of NMF were compared with those of its analogs N-ethylformamide (NEF), N,N-dimethylformamide (DMF), formamide (F), N-methylacetamide (NMA), and N-methyldeuteroformamide ([2H]NMF). Only NEF and [2H]NMF share with NMF the ability to cause liver damage in vivo in mice. Hepatocellular toxicity was determined by measuring LDH leakage into the extracellular medium; metabolism to N-alkylcarbamoylating species was measured by GLC after derivatization with propanol to form propyl N-alkylcarbamate; glutathione concentrations were determined spectrophotometrically. Of the formamide analogs studied, only NMF and NEF caused cytotoxicity, being apparently equipotent. NMF, NEF, and [2H]NMF gave rise to the formation of detectable levels of N-alkylcarbamoylating metabolites and depleted glutathione pools. Toxicity, metabolism, and glutathione depletion were dependent on NMF concentration. [2H]NMF was markedly less cytotoxic than NMF, yielding only 35% of the amount of N-methylcarbamoylating metabolite compared to NMF and caused less depletion of glutathione than did NMF. These results parallel closely the in vivo hepatotoxic potential of NMF and its analogs, their metabolism to urinary S-(N-alkylcarbamoyl)mercapturates and their ability to deplete hepatic glutathione in mice. The results provide support for the contention that metabolism is involved with formamide-induced hepatotoxicity and suggest that suspensions of isolated mouse hepatocytes are an appropriate in vitro model for the further study of the mechanism by which formamides cause toxicity.

Two-phase catalysts in selective oxidation and related reactions

Catalytic properties of mechanical oxide mixtures : Sb 2O 4 + MoO 3 and TiO 2 + V 2 O 5 have been studied in two reactions : N-ethyl formamide dehydration and isobutylene oxidation. An interpretation of the results obtained is proposed on the basis of the remote control concept and an hypothesis about the junction between two cooperating phases.