Methyl Pyrrole Research Articles

Waste-minimized C(sp3)-H activation for the preparation of fused N-heterocycles

By exploiting the combined use of a heterogeneous recyclable palladium(II)-bis(N-heterocyclic carbene) catalyst and cyclopentyl methyl ether (CPME) as a convenient recoverable safer reaction medium, an effective waste-minimized approach has been developed for the intramolecular Pd-catalyzed C(sp3)-H activation of methyl pyrrole derivatives. This synthetic tools has allowed to access condensed N-heterocycles generally endowed with biological activities and representatively are the core motif of complex molecules such as Mitomycines and Tylophorines. The heterogeneous catalytic system could be recovered and reused up to representative five runs without any loss in efficiency. The target products (19 examples) have been obtained selectively and with excellent isolated yields up to 93%. The approach leads to the definition of a protocol with a very good E-factor (21) which is much lower (up to 98%) than those of comparable literature examples. Other green metrics have been calculated and the data collected demonstrate that our newly developed protocol is very promising in terms of its environmental impact profile.

CHEMICAL CONSTITUENTS AND ANTIBACTERIAL ACTIVITY OF Prosopisfarcta (Fabacea) FRUIT FROM IRAQ-KURDISTAN REGION

The chemical constituents of di chloro methane and hexane extracts of Prosopis Farcta (Fabacea family)were studied by gas chromatography, mass spectrometry. Their relative concentrations were determined and both extracts contained 8 expected compounds. There were 7 compounds found in hexane extract which are: 1- methyl pyrrole (8.08%), alpha-ethyl aspartate (9.96%), spiropentane  propyl (13.75%), ethyl oleate (43.43%), 1-iodo-n-Nonyliodide (7.6%), Borane-diethyl (decyloxy) (9.34%), Sulfurous acid, 2-ethyl hexyl ester (7.84%). While one compound was found in dichloromethane extract namely: 3-O-methyl-d-glucose (100%) was recorded as the principle constituents. The antibacterial activities of dichloromethane and hexane extracts were measured against three pathogenic bacteria, which are Staphylococcus aureus, Escherichia coli and Streptococcus Pneumonia using diffusion method. Significant dissimilarities in the antibacterial activity of plant extracts were noticed depending on the type of bacterial strain and the concentration of plant extracts.

ChemInform Abstract: Selective Synthesis of Functionalized Pyrroles from 3‐Aza‐1,5‐enynes.

AbstractEfficient cyclization strategies for the synthesis of functionalized 2‐trifluoromethyl‐5‐(arylsulfonyl) methyl pyrroles, 2‐trifluoromethyl‐4‐(arylsulfonyl) methyl pyrroles, and alkylvinyl pyrroles from the versatile azaenynes are developed.

ChemInform Abstract: Copper‐Catalyzed Enantioselective Friedel—Crafts Alkylation of Pyrrole with Isatins.

AbstractN‐Methyl pyrrole, furan and thiophene do not react with (Ia).

Synthesis of a mitomycin C–lexitropsin hybrid

Abstract We have constructed hybrid drugs where mitomycin C is linked to the N -methylpyrrole carboxamide framework present in lexitropsins. The coupling reactions leading to these products are efficient and the yields are very high. An interesting spectroscopic feature of these hybrids is the red shift observed in the UV–vis spectrum. Although DFT calculations indicate the possible existence of complexes formed during the coupling reactions, these complexes were not detected. The only species produced and isolated were the mitomycin C-mono- and bis- N -methyl pyrrole conjugates.

New N-methyl pyrrole and thiophene based D–π–A systems for dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) containing novel DP-T and DP-P organic sensitizers having thiophene and N -methyl pyrrole moieties as π bridges in a D–π–A system were assembled and characterized. Incorporation of a thiophene bridge to give sensitizer DP-T enhanced solar energy capture, while impedance spectroscopy showed a much longer electron recombination lifetime ( τ ) for the DSSCs based on pyrrole containing sensitizer DP-P . The observed kinetics led to increased open circuit voltage ( V oc ) for the device based on DP-P , regardless of types of additives (TBP or DCA) employed in the devices. Better photovoltaic performance was achieved using DP-T . ► New sensitizers having N -methyl pyrrole or thiophene π-spacers were incorporated into DSSCs. ► The DSSC device based N -methyl pyrrole showed good kinetic properties, resulting in a high V oc . ► Molecular modeling studies were used to predict electronic energies and densities.

Circuit Model Evaluation of Poly(methyl pyrrole-co-2-(9H-carbazole-9-yl)ethyl methacrylate) on Carbon Fiber

Methyl pyrrole (N-MPy) and 2-(9H-carbazole-9-yl) ethyl methacrylate (CzEMA) monomers were electrocopolymerized on carbon fiber microelectrode (CFME) as an active electrode material. The electropolymerization of monomers was studied in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (ACN) solution. The detailed characterization of the resulting electrocoated poly(N-MPy-co-CzEMA)/CFME thin films was studied by various techniques, i.e., cyclic voltammetry (CV), Scanning electron microscopy – Energy Dispersive X-ray analysis (SEM-EDX), and Electrochemical impedance spectroscopy (EIS). The effects of monomer mole fractions (mole fraction, XCzEMA = nCzEMA/nMPy + nCzEMA) (0.5, 0.66, 0.75, 0.83 and 0.91) during the preparation of modified electrodes were examined by EIS. Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode-magnitude, Bode-phase and Capacitance plots. Circuit model of R(Q(R(C(R(C(RW))))))(CR) was suggested to fit the theoretical and experimental values. The lowest low frequency capacitance value and total charge (Q = 112.9 mC) during electrodeposition of polymer thin film by CV method in the mole fraction of XCzEMA = 0.75 (CLF = ∼27.2 mF cm−2). However, the highest double layer capacitance of polymer/electrolyte system (C1 = 25.4 mF cm−2; C2 = 159.1 mF cm−2; C3 = 4.54 mF cm−2) was obtained in the same mole fraction.

The Preparation of Several Novel Organic Material of Neutral Molecules Recognition

Several novel organic material were Prepared by condensation between p-aminophenyl methyl keton, 3,5-Dicholoro-4-aminophenyl methyl keton and 5-Dibromo-4-aminophenyl methyl keton and pyrrole. The reaction condition has been optimized. The structure was characterized by 1HNMR and elemental analysis.

Potentiation of Helicobacter pylori CagA Protein Virulence through Homodimerization

Chronic infection with Helicobacter pylori cagA-positive strains is associated with atrophic gastritis, peptic ulceration, and gastric carcinoma. The cagA gene product, CagA, is delivered into gastric epithelial cells via type IV secretion, where it undergoes tyrosine phosphorylation at the EPIYA motifs. Tyrosine-phosphorylated CagA binds and aberrantly activates the oncogenic tyrosine phosphatase SHP2, which mediates induction of elongated cell morphology (hummingbird phenotype) that reflects CagA virulence. CagA also binds and inhibits the polarity-regulating kinase partitioning-defective 1 (PAR1)/microtubule affinity-regulating kinase (MARK) via the CagA multimerization (CM) sequence independently of tyrosine phosphorylation. Because PAR1 exists as a homodimer, two CagA proteins appear to be passively dimerized through complex formation with a PAR1 dimer in cells. Interestingly, a CagA mutant that lacks the CM sequence displays a reduced SHP2 binding activity and exhibits an attenuated ability to induce the hummingbird phenotype, indicating that the CagA-PAR1 interaction also influences the morphological transformation. Here we investigated the role of CagA dimerization in induction of the hummingbird phenotype with the use of a chemical dimerizer, coumermycin. We found that CagA dimerization markedly stabilizes the CagA-SHP2 complex and thereby potentiates SHP2 deregulation, causing an increase in the number of hummingbird cells. Protrusions of hummingbird cells induced by chemical dimerization of CagA are further elongated by simultaneous inhibition of PAR1. This study revealed a role of the CM sequence in amplifying the magnitude of SHP2 deregulation by CagA, which, in conjunction with the CM sequence-mediated inhibition of PAR1, evokes morphological transformation that reflects in vivo CagA virulence.

Electropolymerization of poly(methyl pyrrole)/carbon nanotubes composites derived from ionic liquid

AbstractThe use of conjugated polymer in electronics devices is believed to be the driving force for the tremendous R & D activity involving these materials. In this study, electropolymerization of N‐methyl pyrrole/carbon nanotubes composites has been performed galvanostatically in ionic liquid medium. A well‐ordered polymer composites of poly(methylpyrrole)/carbon nanotubes (pMPy/CNTs) nanostructures has been observed as revealed by atomic force microscopy. The current vs. voltage curves demonstrates an ohmic nature of the synthesized polymers. pMPy/CNT films are found more conductive than the pMPy films. It is believed that, this route can be further fined to other organic conjugated systems and, thus, opens an avenue for application for a host of polymers in electronic devices. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Hydrocarbons generated by hydropyrolysis of suspended marine particulate organic matter: Relationship to the oceanography of the Black Sea and the Rhodes Gyre

The suspended particulate organic matter, SPOM, in the autumnal Black Sea has been characterised using catalytic hydropyrolysis (HyPy) of the total (bound plus free) lipid material. The technique, which generates maximum yields of volatile products from sediments, kerogens and phytoplankton, was followed using gas chromatography and gas chromatography/mass spectrometry. The generated alkanes were dominated by n-C18, hypothesised to arise predominantly from unsaturated C18 fatty acids. Steranes were generated from reductive conversion of free and bound sterols. The generation of branched alkanes and especially of hopanes provided formal evidence for the participation of bacteria in the mineralisation of the SPOM. Whereas similar distributions of n-alkanes were generated from SPOM sampled from different depths of the comparatively well-stirred Rhodes Gyre (eastern Mediterranean), mineralisation of the SPOM at each depth of the central Black Sea produced characteristic changes in the composition and concentration of the HyPy products. Depth profiles of the n-alkanes generated from SPOM in the region of the Rim Current were affected by the local hydrography. Polynuclear aromatic hydrocarbons (PAHs) of anthropogenic origin were present in the surface waters of the central Black Sea. Some methyl benzenes, thiophenes and pyrroles were also generated.

Electrochromic device based on carbon nanotubes functionalized poly (methyl pyrrole) synthesized in hydrophobic ionic liquid medium

A facile approach of carbon nanotubes (CNTs) functionalized poly(methylpyrrole) [pMPy] electrosynthesized in hydrophobic ionic liquid for fabrication of electrochromic (EC) devices is discussed. Clear change from brown (oxidized) to pale yellow (neutral) color is demonstrated with robust cycle life. This synthesis route can be exploited to fabricate polymers from other organic conjugated systems and provide an avenue for applications requiring stable redox polymers in electrochromic devices.

In Situ Fabrication of Single Poly(methyl pyrrole) Nanowire

AbstractOne hundred nm wide by four μm long poly(methyl pyrrole) (PMPy) nanowires without and with biomolecule, biotin‐quantum dot, were synthesized by electrochemical polymerization of 1‐methyl pyrrole with chloride and p‐toluene sulfonate dopants in nanochannels between microfabricated gold electrodes. Scanning electron microscopy examination revealed well‐confined dendrite free chloride‐doped PMPy nanowires with embedded biotin‐quantum dot. Current vs. voltage investigation demonstrated ohmic nature of contact for all nanowires. Chloride‐doped PMPy nanowires were more conductive than with p‐toluene sulfonate doped PMPy nanowires whereas entrapment of biotin‐quantum dot increased the conductivity.

Thermal release of nitrogen organics from natural organic matter using micro scale sealed vessel pyrolysis

Characterisation of recent organic matter such as aquatic natural organic matter (NOM) can be aided by the artificial maturation provided by closed system, micro scale sealed vessel (MSSV) pyrolysis. Gas chromatography–mass spectrometry (GC–MS) analysis of the products released via MSSV pyrolysis of several NOM fractions showed complex and varied product distributions that included a range of nitrogen-containing organic products (N organics) such as pyrroles, pyridines, pyrazines, indoles and carbazoles. N organics were found in highest abundance in the products from the transphilic and colloid fractions of NOM. A larger number and great abundance of N organics were detected with MSSV pyrolysis than with flash pyrolysis of the same samples. To better understand the sources of N organic products detected with MSSV pyrolysis of NOM, the distinctive N pyrolysate distributions from several likely precursors (i.e. peptide, amino sugar, porphyrin and a cultured bacterium) of dissolved organic nitrogen are reported. A number of qualitative distinctions between these precursors were evident, such as high abundances of C 1–3 pyrroles from the amino sugar and C 4–5 pyrroles from the porphyrin. The thermal profile of the N organic products from the pentaglycine and porphyrin standards was established by analysing these samples using several different MSSV temperatures. The abundance of the N organics in most pyrolysates increased with temperature, but the relatively constant ratio of particular N organic product abundances (e.g. ethyl dimethyl pyrrole/diethyl methyl pyrrole) suggests these may be useful for source distinction across a broad range of thermal analytical conditions.

Synthesis and Structure Characterization of 2‐(Dimethylaminomethyl)pyrrolate and 2,5‐Bis(dimethylaminomethyl)pyrrolate Zirconium Complexes

AbstractTetrakis(diethylamido)zirconium reacts with 2‐(dimethylamino)methyl pyrrole (DMAMP) and 2,5‐[bis(dimethylamino)methyl]pyrrole (BDMAMP) to give Zr(NEt)2(DMAMP)2 1 and Zr(NEt)3(BDMAMP) 2, respectively. Both 1 and 2 have been characterized by 1H and 13C NMR spectroscopies and 1 has also been characterized by X‐ray crystallography. Complex 1 shows an agostic interaction between Zr and H(21A) in solid state that is not sustained in solution. Reacting 1 with 2 equivalents of trimethylsilyl chloride in toluene yields ZrCl2(DMAMP)2 3 in 75% yield which was characterized by 1H and 13C NMR spectroscopies.

Volatile Compounds in the Production of Liquid Beet Sugar

Samples from different parts of a beet sugar factory and refinery were analyzed with respect to volatile compounds by means of liquid-liquid extraction followed by gas chromatography-mass spectrometry (GC-MS). A limited number of the samples were analyzed by means of gas phase extraction (headspace) followed by GC-MS. Selected compounds were followed through the sugar manufacturing process. The behavior of different compounds varied greatly throughout the process, with some compounds such as geosmin (trans-1, 10-dimethyl-trans-9-decalol), dimethyl disulfide, and propionic and hexanoic acid present at the beginning of the process but disappearing rapidly after further processing. Other compounds, such as indole, dihydrobenzofuran, and 2-phenylethanol, were not detected at the start of the process but were formed later on and removed in the final product. In the final product, three pyrazines remained at fairly low concentrations, together with 3-methylcyclopentadione, ethylhexanol, and methyl pyrrole ketone.

Characterization of soil humin by pyrolysis(/methylation)-gas chromatography/mass spectrometry: structural relationships with humic acids

Pyrolysis-gas chromatography /mass spectrometry (Py-GC/MS) and Py-GC/MS in the presence of tetramethylammonium hydroxide (TMAH) (pyrolysis methylation-GC/MS) have been used to characterize humin of a representative agricultural soil. Analyses have been performed on humin de-ashed by treatment with HCl-HF (HU) and the results have been compared with those obtained from the corresponding humic acid (HA). Both semiquantitative conventional pyrolysis and pyrolysis methylation agreed in showing that the pyrolytic behaviour of HU is quite different from that of HA, the mass spectrometry pyrograms of the former being characterized by a larger amount of carbohydrates and aliphatic compounds. Pyrolysis/methylation of HU produced methyl esters of aliphatic and aromatic carboxylic acids, methylated carbohydrate derivatives and methyl pyrroles. Peaks diagnostic of the presence of glucose and cellulose have been proposed when pyrolysis is performed in the presence of TMAH.

Fatty Acid Composition, Mineral Content, and Flavor Quality of Southern Runner Peanuts Treated With Herbicides and Fungicides1

Abstract The application of herbicides and fungicides (chemical compounds used to control weed and fungal pests, respectively) generally improve peanut yield and grade, however their effect on peanut composition and flavor quality is not well documented. The effects of herbicides or fungicides and their combinations on mineral content, fatty acid composition and flavor quality of Southern Runner peanut were investigated. Fungicide application [chlorothalonil (C) and diniconazole (D)] alone or in combination, improved the yield. Application of most herbicides or fungicides or their combination decreased the long chain saturated fatty acid, eicosenoic acid (20:1), acetone, methyl pyrrole and hexanal content while increasing pyrazine content. Application of imazquin (I) and most of the combinations increased magnesium (Mg) while decreased zinc (Zn) content. Application of benefin (B), metolachor (M), alachlor (A), (B+V), (M+C), and (M+D) increased the oleic linoleic acid (O/L) ratio which should improve the stability of the peanuts. Application of (B+V+A) decreased the flavor intensity of the roasted peanuts. Application of pesticides affected fatty acid composition and flavor quality of Southern Runner peanuts.

α-(Dialkylamino)-α-pyrrolylacetonitriles. A potpourri of useful synthetic transformations

α-(Dialkylamino)-α-(pyrrol-2-yl)acetonitriles (3) are versatile intermediates that are readily converted into regiochemically pure 2-bromo-6-dialkylamino-1-azafulvenes and 5-bromo-2-acylpyrroles (acyl = CHO, COR). In addition, 3 (R1 = H), 4 (R1 = H), and the β-substituted compound 9 are transformed easily and under mild conditions, via the corresponding α-methylthio compounds (e.g., 7a), into the methyl pyrrole carboxylates 8a, 8b, and 10, respectively. Keywords: α-(dialkylamino)-α-(pyrrol-2-yl)acetonitriles, 5-bromo-2-acylpyrroles, methyl pyrrole carboxylates.

Resonantly enhanced multiphoton ionization of pyrrole, N-methyl pyrrole, and furan

The resonantly enhanced multiphoton ionization (REMPI) spectra of pyrrole (C4H5N), N-methyl pyrrole (C5H7N), and furan (C4H4O) have been measured in the wavelength region from 365 to 680 nm. New and previously observed Rydberg states are reported for pyrrole and furan. Vibrational constants are presented for most of the Rydberg series. Accurate ionization potentials are derived for pyrrole (8.207±0.003 eV) and N-methyl pyrrole (7.94±0.02 eV). A strong two photon allowed transition is observed in N-methyl pyrrole at 41 193 cm−1 (0,0) and is attributed to an 1A2 state. The corresponding state is not seen in pyrrole; however, it may be obscured by overlapping Rydberg series. Mass spectra following REMPI for benzene, pyrrole, and furan are reported. The degree of ionic fragmentation depends upon laser power density and wavelength.