Theoretical characterization of the adsorption configuration of pyrrole on Si(100)surface by x-ray spectroscopy

The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS spectra of these adsorption configurations have been calculated by using the density functional theory(DFT)method and fullcore hole(FCH)approximation to investigate the relationship between the adsorption configurations and the spectra.The result shows that the XPS and NEXAFS spectra are structurally dependent on the configurations of pyrrole absorbed on the Si(100)surface.Compared with the XPS,the NEXAFS spectra are relatively sensitive to the adsorption configurations and can accurately identify them.The NEXAFS decomposition spectra produced by non-equivalent carbon atoms have also been calculated and show that the spectral features vary with the diverse types of carbon atoms and their structural environments.

Selectively reductive amination of levulinic acid with aryl amines to N-substituted aryl pyrroles

Synthesizing nitrogen(N)-containing molecules from biomass derivatives is a new strategy for production of this kind of chemicals.Herein,for the first time we present the synthesis of N-substituted aryl pyrroles via reductive amination/cyclization of levulinic acid(LA)with primary aromatic amines and hydrosilanes(e.g.,PMHS)over Cs F,and a series of N-substituted aryl pyrroles could be obtained in good to excellent yields at 120○C.The mechanism investigation indicates that the reaction proceeds in two steps:the cyclization between amine and LA occurs first to form intermediate 5-methyl-N-alkyl-1,3-dihydro-2H-pyrrolones and their isomeride(B),and then the chemo-and region-selective reduction of intermediates take place to produce the final products.This approach for synthesis of N-substituted aryl pyrroles can be performed under mild and green conditions,which may have promising applications.

Synthesis of Calix[4]pyrroles: A Class of New Molecular Receptor

Calix[4]pyrroles, as a class of new molecular receptor in the area of supramolecular chemistry, have displayed interesting anion and neutral substrate binding properties. In this paper, several new calix[4]pyrrole macrocycles were synthesised and characterized.

THE POLYMERIZATION THERMOKINETICS OF PYRROLE IN THE PRESENCE OF IRON TRICHLORIDE

The polymerization thermokinetics of pyrrole in the presence of iron trichloride art studied by using a Calvet microcalorimoter. The apparent activation energy, the pre-exponential constant and reaction order of this reaction in the temperature range of 25.2—37℃ are 34.5 KJ·mol^(-1), 10^(2.74)S^(-1) and 1 respectively. The activation free-energies of this reaction at 25.2°, 30°and 37℃ are 91.8, 92.9 and 94.2 KJ·mol^(-1) respectively.

Novel MWCNT-Support for Co-Mo Sulfide Catalyst in HDS of Thiophene and HDN of Pyrrole

With home-made multi-walled carbon nanotubes （MWCNTs, simplified as CNTs in later text） as support, CNT-supported Co-Mo-S catalysts, denoted as x%（mass percentage）MoiCoj/CNTs, were prepared. Their catalytic performance for thiophene hydrodesulfurization （HDS） and pyrrole hydrodenitrification （HDN） reactions was studied, and compared with the reference system sup- ported by AC. Over the 7.24%Mo3Co1/CNTs catalyst at reaction condition of 1.5 MPa, 613 K, C4H4S/H2=3.7/96.3（molar ratio） and GHSV≈8000 mlswP/（g-cat.h）, the specific HDS activity of thiophene reached 3.29 mmolc4H4S/（s.molMo）, which was 1.32 times as high as that （2.49 mmolc4H4S/（s.molMo）） of the AC-based counterpart, and was 2.47 times as high as that （1.33 mmolc4H4S/（s-molMo）） of the catalysts supported by AC with the respective optimal MoaCol-loading amount, 16.90%Mo3Co1/AC. Analogous reaction-chemical behaviours were also observed in the case of pyrrole HDN. It was experimentally found that using the CNTs in place of AC as support of the catalyst caused little change in the apparent activation energy for the thiophene HDS or pyrrole HDN reaction, but led to a significant increase in the concentration of catalytically active Mo-species （Mo^4＋） at the surface of the functioning catalyst. On the other hand, H2-TPD measurements revealed that the CNT-supported catalyst could reversibly adsorb a greater amount of hydrogen under atmospheric pressure at temperatures ranging from room temperature to about 673 K. This unique feature would help to generate microenvironments with higher stationarystate concentration of active hydrogen-adspecies at the surface of the functioning catalyst. Both factors mentioned above were favorable to increasing the rate of thiophene HDS and pyrrole HDN reactions.

Gallium trichloride-catalyzed conjugate addition of indole and pyrrole to α,β-unsaturated ketones in aqueous media

Michael addition of indole and pyrrole to a variety of α, β-unsaturated ketones was efficiently promoted by a catalytic amount of GaCl3 in aqueous media to afford the corresponding products in good to excellent yields.

A convenient synthesis of pyrroles catalyzed by acidic resin under solvent-free condition

A convenient and effective Paal-Knorr condensations of 2,5-hexanedione with most amines have been carried out at room temperature under solvent-free condition.Macroporous strongly acidic styrol resin(D001) as a novel,efficient,cost-effective,and reusable solid acid catalyst for the synthesis of pyrroles under the same conditions.The pyrroles were obtained in high yields in short reaction times.

Pyrrole derivatives as interlayer modifier of Li-S batteries:Modulation of electrochemical performance by molecular perturbation

The electrochemical performance of lithium-sulfur(Li-S)batteries is strongly hampered by the shuttle effect and slow redox kinetics of lithium polysulfides(Li PSs).Surface modified interlayer of a separator of Li-S batteries is demonstrated to be an effective strategy to overcome this problem.Herein,cobalt nanoparticles confined in nitrogen co-doped porous carbon framework(Co-CN)were developed from pyrolysis of ZIF-67 and used as interlayer of PP separator for Li-S batteries,and were functionalized by four pyrrole derivatives,1-phenylpyrrole,1-methyl pyrrole,1-(p-toluenesulfonyl)pyrrole,and 1-pyrrole,respectively,which were screened in terms of the electron-withdrawing/donating ability of the substituent groups on the pyrrolic nitrogen.The impact of the molecular structure of pyrrole derivatives on the interaction with Li PSs and the electrochemical performance of Li-S batteries were explored by nuclear magnetic resonance and theoretical calculation.It is uncovered that 1-phenylpyrrole shows the highest enhancement of redox kinetics of Li PSs,attributing to the optimal interaction with Co nanoparticles and Li PSs.Therefore,1-phenylpyrrole modified Co-CN interlayer enables the best electrochemical performance for the Li-S batteries,delivering a specific capacity of 562 m Ah g^(-1)at 5 C and a capacity of 538,526,and 449 m Ah g^(-1)after 500 cycles at 1,2,and 3 C,respectively.At a high sulfur loading of 5.5 mg cm^(-2),it achieves a capacity of 440 m Ah g^(-1)after 500 cycles at 1 C.This work reveals the interaction mechanism among Li PSs,Co nanoparticles and the molecular modifiers in improving the electrochemical performance of Li-S batteries.

Lagerindicine, a New Pyrrole Alkaloid Isolated from the Flowers of Lagerstroemia indica Linnaeus

A phytochemical investigation of the EtOH extract of the flowers of Lagerstroemia indica L.led to the isolation and char-acterization of a new pyrrole alkaloid,named lagerindicine(1),along with four known compounds(2-5).Their structures were elucidated by the detailed spectroscopic analysis and comparison with literature data,whereas the structure,in par-ticularly,the absolute configuration(AC)of 1,was firmly determined by total synthesis.All the isolates were evaluated for their cytotoxic effects against human colon cancer cell(HCT-116),and compound 3 exhibited weak cytotoxicity with IC50 value of 28.4μM.

Three new pyrrole alkaloids from the endophytic fungus Albifimbria viridis

Three new pyrrole alkaloids albifipyrrols A-C(1-3),were isolated from the endophytic fungus Albifimbria viridis col-lected from the Chinese medicinal plant.Their structures were elucidated by extensive NMR and HRESIMS spectro-metric analyses.All compounds were evaluated for immunosuppressive activity.Fortunately,compound 2 exhibits certain inhibition specifically against the LPS-induced proliferation of B lymphocyte cells with IC50 value 16.16μM.

Effect of Calix[4]pyrrole as Addition Reagent on Anions Separation in Capillary Zone Electrophoresis (CZE)

Supramolecular interaction of calix[4]pyrroles with several inorganic anions is reported by addition of calix[4]pyrroles to background electrolyte (BGE) in CZE. The retention time (t(R)) of all anions increased with increasing concentration of calix[4]pyrroles. The effect on F- is most evident.

Synthesis of Pyrrole-Imidazole Polyamide

One simple and versatile method is established far the synthesis of DNA recognition molecules-polyamides containing alternating N-methylpyrrole and N-methylimidazole without necessitating NH2- group protection.

Synthesis of Pyrroles and Condensed Pyrroles as Anti-Inflammatory Agents with Multiple Activities and Their Molecular Docking Study

We herein disclose a series of novel pyrrole derivatives as well as fused pyrrolopyridines 6a,b and 7a,b, pyrrolopyrazoles 8a, b, pyrrolo[2,3-d]pyrimidine derivatives 10a-d, 12a,b, 14a,b, 18a,b, 20a,b, 21a,b, 22a,b, 23a,b, 24a,b, 31a,b, 36a,b, 40a,b, pyrrolo[1,2,6]thiadiazine derivatives 19a,b, pyrrolotriazolopyrimidines 25a,b, 26a,b, 27a,b and 28a,b, pyrrolo[2,3-d][1,2,3]triazine derivatives 32a,b and pyrrolo[2,3-d][1,3]oxazine derivatives 39a,b as novel compounds. All compounds were evaluated for their anti-inflammatory, analgesic (compared to the reference drug Indomethacin) and antimicrobial activities (compared to the reference drug Ampicillin and Fluconazole). Compounds 4d, 5b-d, 6a,b, 9c,d, 10d, 12ab, 13b, 19a,b, 21b, 23b, 31a,b, 38b and 40a were found to be the most active anti-inflammatory drugs exhibiting potency ranging from 1 - 1.01 compared to the reference drug indomethacin. In addition to docking study of these highly active twenty compounds against the active site of cyclooxygenase-2 enzyme (COX-2), among the tested compounds, compounds 5d, 9d, 11b, 12a, 13b and 32a showed multiple activities;anti-inflammatory, analgesic and anti-bacterial activities.

DABCO Promoted an Efficient and Convenient Synthesis of Pyrrole in Aqueous Medium

The synthesis of C-substituted and N-substituted pyrrole is described by the reaction of phenacyl bromides, pentane-2, 4-dione and amine in aqueous medium using DABCO as a catalyst. The method is very convenient and applicable for alkyl as well as aryl amines and phenacyl bromides. The procedure is amenable for the synthesis of new substituted pyrroles. Moreover, aqueous medium makes the method more eco-friendly.

Separation of Phenolic Compounds and Organic Anions Using ODS Column Coated with Meso-octamethylcalix[4]pyrrole and Water as Eluent

Octadecylsilanized silica (ODS) was coated with meso-octamethylcalix[4]pyrrole to obtain a novel calix[4]pyrrole containing stationary phase for HPLC. Compared to ODS, the new stationary phase showed a relatively large retention and an improved separation for phenolic compounds and organic anions, using pure water as mobile phase. The results can be ascribed to the interaction between analytes and calix[4]pyrrole.

Alkylations of Resorcarenes and Calix[4]pyrroles in Phase Transfer Catalytic Systems

Resorcarens 1a-b (R'=Ph, p-MeOC6H4) were fully alkylated with alkyl iodides or bromides in TEBA/KOH/DMF solid-liquid PTC process with 63-82% yields, whereas the three calix[4]pyrroles 3a-b (2R= 2Me, (CH2)(4), (CH2)(5)) were alkylated with alkyl iodides in TBAB/ 50%NaOH/ CH2Cl2 liquid-liquid PTC system with lower yields (10-38%).

Discovery of novel thieno[3,2-b]pyrrole 5-carboxamides as potent inhibitors of Chikungunya virus

Chikungunya fever(CHIKF)is an arboviral disease that typically consists of an acute illness with fever,skin rash,and incapacitating arthralgia.The causative agent of CHIKF is Chikungunya virus(CHIKV),an alphavirus that is transmitted by the Aedes mosquitoes.Despite the re-emergence of CHIKV as an epidemic threat,there is no approved effective anti-viral treatment currently available for CHIKV.In our preliminary studies,selected small molecule inhibitors of arboviruses related to CHIKV were investigated and this led us to identify compounds with thieno[3,2-b]pyrrole scaffold as hits.Building on the discovery of our best hit compounds,5-carboxylic acid thieno[3,2-b]pyrrole 1 and 5-carboxamide thieno[3,2-b]pyrrole 2,the main aim of this study is to optimize their anti-viral activities by synthesizing analogs of thieno[3,2-b]pyrroles 1 and 2 and examine their activities against CHIKV.In these two parallel optimization studies,we synthesized two series of thieno[3,2-b]pyrroles,namely the 5-carboxylic acids and 5-carboxamides that possessed a variety of substituents at N4,C2,C6 or C5positions of the thieno[3,2-b]pyrrole scaffold.These compounds were then examined for their cytotoxicity effects and anti-viral activities using a luminescence-labelled CHIKV infectious clone.The most potent compound in our studies was found in the 5-carboxamide series.The synthesis,biological activity and structure-activity relationship(SAR)will be presented and discussed in detail.

CHANGES OF STRUCTURE AND PROPERTIES OF POLY (ETHYLENE TEREPHTHALATE) CAUSED BY IN-SITU POLYMERIZATION OF PYRROLE

Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly （ethylene terephthalate） （PET） film. The DSC and WAXD measurement and SEM observation show that liquid-induced crystallization of PET matrix has occurred during the preparation of composite films. Depending upon the equilibrium degree of swelling and crystallinity, the limited depth of penetration of pyrrole molecules results in a skin-core structure of the composite film. The skin layer containing charge transfer intercalated polypyrrole has a surface resistance of 3.5×10;Ω. Rigid and heat-resistant polypyrrole molecules formed in PET film increase the tensile modulus and, especially, the rigidity of PET at elevated temperatures. However, they decrease the tensile strength and elongation at break, and impair the thermal ductility of PET.

New Subsidiary Interaction Mode of Counteranions with the Periphery Cavity of Calix[4]pyrroles Binding with the Anion Subunits

The solution binding properties of calix[4]pyrroles with anion （as tetraalkylammonium salts） were investigated using UV-Vis spectroscopic techniques. The obvious red-shift of absorption maximum band of calix[4]pyrrole in EtOH in the presence of the tetramethylammonium （TMA^＋） salts or tetraethylammonium （TEA^＋） salts were observed, due to the charge-transfer interactions between the electron-rich pyrrole rings of calix[4]pyrroles and TMA^＋ or TEA^＋ cation subunit. The results indicated that calix[4]pyrrole receptors, which link the anionic species through multiple hydrogen bonding interactions, can use the periphery cavity for selectively binding cation subunits by cation-π charge-transfer interaction. The subsidiary interaction mode helps to further stabilize the calix[4]pyrrole-anion complex.