- Preparation, spectral and thermal properties of Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes with iodosubstituted 2,2′-dipyrrolylmethene
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Complexes [ML2] of cobalt(II), nickel(II), copper(II), zinc(II), and cadmium(II) with asymmetrically substituted (E)-3-ethyl-5-[(4-iodo-3,5- dimethyl-2H-pyrrol-2-ylidene)methyl]-2,4-dimethyl-1H-pyrrole (HL) have been prepared and characterized for the first time. The spectral properties, stability in solutions and in the solid phase at elevated temperature of the complexes have been studied. The effects of complexing metal ion and the reaction medium on the spectral luminescent properties (absorptivity, quantum yield, fluorescence lifetime, and the radiation constant) and on thermal destruction of the [ML2] complexes have been discussed.
- Guseva,Antina,Beresin,V'Yugin,Nuraneeva
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- Synthesis and spectral properties of new 3,3'-bis(dipyrrolylmethene) with acetylene spacer
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Bis(2,4,7,9-tetramethyl-8-ethyldipyrrolylmethen-3-yl)acetylene dihydrobromide (H2L·2HBr), new bis(dipyrrolylmethene), in whose molecule dipyrrolylmethene domains were connected through 3,3'-carbon atoms of internal pyrrole nuclei by acetylene spacer, were synthesized by original procedure. The compound was characterized by element analysis, IR, 1H NMR, and electronic spectroscopy. The comparative analysis of spectral properties shows the reduction of the basicity of H2L ligand in comparison with the structural analogs, which contain internal methylene spacer. The quantum-chemical simulation showed that the rigid acetylene spacer gives linear structure to the H2L molecule in contrast to the spiral-shaped geometry of structural analogs with-CH2-spacer. Pleiades Publishing, Ltd., 2010.
- Antina,Guseva,Loginova,Semeikin,V'Yugin
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- Syntheses of per-15N labeled etioporphyrins I-IV and a related tetrahydrobenzoporphyrin for applications in organic geochemistry and vibrational spectroscopy
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Nitrogen-15 labeled pyrroles have been prepared from commercially available 15N glycine or sodium nitrite using the Barton-Zard, Knorr, and Kleinspehn approaches. These pyrroles were used as intermediates in the synthesis of per-15N labeled porphyrins needed for the analysis and assignment of vibrational spectra for sedimentary porphyrins. Etioporphyrin-I was prepared via pyrromethene intermediates, while etioporphyrins II-V and a related tetrahydrobenzoporphyrin were synthesized via stepwise routes involving the copper(II) mediated cyclization of a,c-biladienes as the key step. Detailed analyses of both the proton and carbon-13 NMR spectra provide nitrogen-15 coupling constants for these important structures.
- Lash, Timothy D.,Chen, Shaohua
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p. 11577 - 11600
(2007/10/03)
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- Reduction of acyl pyrrole esters by zinc-hydrochloric acid
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The pyrryl alkyl ketone and acetylpyrrole esters were reduced to corresponding alkylpyrrole esters by zinc-hydrochloric acid in alcohol in high yields (> 90%).
- Cheng,Ma
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p. 2771 - 2775
(2007/10/02)
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- Thermochemistry of substituted pyrroles
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The heats of solution of a series of substituted pyrroles in benzene, carbon tetrachloride, chloroform, DMF, and pyridine were measured by a calorimetric method at 298.15 K.The influence of substituents in the pyrrole molecule on the energy parameters of solvation by organic solvents is discussed.
- Berezin, M. V.,Semeikin, A. S.,V'yugin, A. I.,Krestov, G. A.
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p. 449 - 453
(2007/10/02)
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- SYNTHESIS OF MESO-DIPHENYLOCTAALKYLPORPHYRINS
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Procedures were developed for the synthesis of phenyl(β-tetraalkyldipyrrolyl)methanes.On their basis 3,7,13,17-tetramethyl-2,8,12,18-tetrabutyl-5,15-diphenylporphyrin, 2,8,12,18-tetramethyl-3,7,13,17-tetrabutyl-5,15-diphenylporphyrin, 2,8,12,18-tetramethyl-3,7,13,17-tetraethyl-5,15-diphenylporphyrin, and derivatives of the last two porphyrins containing electron-donating (2-CH3O, 3-CH3O, 4-CH3O) and electron-withdrawing (3-NO2, 4-NO2) substituents in the benzene rings were obtained.
- Mamardashvili, N. Zh.,Semeikin, A. S.,Golubchikov, O. A.
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p. 1007 - 1015
(2007/10/02)
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- ELECTROPHILIC HETEROAROMATIC SUBSTITUTIONS. X. UNEXPECTED RESULTS IN THE α-SIDE-CHAIN CHLORINATION OF A SERIES OF ETHYL 3,4,5-TRIALKYLPYRROLE-2-CARBOXYLATES
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The reaction of a series of 3,4,5-trialkyl-substituted ethyl pyrrole-2-carboxylates with an excess of sulphuryl chloride followed by solvolysis has been investigated in several solvents and under different experimental conditions.In all cases, beside the expected α-side-chain substituted product, substantial amounts of derivatives functionalised also in a β-side chain have been isolated and identified.The process turned out to be electrophilic in nature and to involve allylic migration of the halogen from the α-sigma adduct to the adjacent β-side chain.Virtually identical results have been obtained when elemental chlorine was used.
- Scarsella, Marco,Sleiter, Giancarlo
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p. 757 - 762
(2007/10/02)
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- Pyrrole Chemistry. An Improved Synthesis of Ethyl Pyrrole-2-carboxylate Esters from Diethyl Aminomalonate
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Ethyl pyrrole-2-carboxylates, versatile precursors for the total synthesis of both synthetic model and naturally occurring tetrapyrroles and porphyrins, can be prepared in greatly improved yields by the addition of 1,3-diketones and preformed diethyl aminomalonate to boiling glacial acetic acid.The method is suitable for both small- and large-scale synthesis and has proved far more reliable than the original in situ dissolving zinc reduction of diethyl oximinomalonate discovered by Kleinspehn.Yields range from 60-70percent for the dominant product isomer from unsymmetrical diketones to 75-90percent for the single product derived from symmetrical diketones.Seventeen examples of alkyl-substituted ethyl pyrrole-2-carboxylates are provided.Improved procedures are given for the preparation of the required precursors.
- Paine, John B.,Dolphin, David
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p. 5598 - 5604
(2007/10/02)
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- Alkylation process
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Substituted pyrrole compounds, such as 3-ethyl-4-methyl-5-carbethoxy pyrrole, 2,4-dimethyl-3-acetyl pyrrole and 2-methyl-5-carboxy pyrrole-4-propionic acid diethyl ester, are alkylated in a single step by reaction with an aldehyde or ketone in the presence of both an acid condensing agent such as hydriodic acid and a compatible reducing agent such as metallic zinc or stannous chloride. Suitable carbonyl reactants include formaldehyde, paraldehyde, isobutyraldehyde, acetone, cyclohexanone and methyl-isobutyl ketone. This application is a continuation application of U.S. application Ser. No. 281,624 filed Aug. 18, 1972, now abandoned, which is a continuation-in-part application of U.S. application Ser. No. 832,001, filed June 10, 1969, now abandoned.
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