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Pyrrole Derivatives (pyrrole + derivative)
Selected Abstracts2H -Pyrrole Derivatives from an Aza-Nazarov Reaction Cascade Involving Indole as the Neutral Leaving GroupEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2008Nugzar Ghavtadze Abstract Trifluoromethyl-substituted N -indolinyl-1-aza-1,4-dien-3-ones 4, which are accessible in good yields from indolinylimino esters 6 in a two-step procedure, undergo a novel type of aza-Nazarov cyclization if treated with strong acids to give the hitherto unknown 3-hydroxy-5H -pyrrole derivatives 8a,p. The solvent-free polyphosphoric acid/acyl anhydride system as the acidic reaction medium is especially efficient and requires only short reaction times. According to quantum chemical calculations the key step in the reaction cascade is the cleavage of the N,N bond of the hydrazone fragment of a protonated N -(indolin-1-yl)-1-aza-1,4-dien-3-one intermediate such as 10. This intermediate releases 3H -indole as an unusual, but very efficient neutral leaving group. Several 1-aza-1,4-dien-3-ones 4 and some 3-hydroxy-5H -pyrrole derivatives 8 were characterized by X-ray diffraction.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis of Pyrrole Derivatives through Functionalization of 3,4-Bis(lithiomethyl)dihydropyrrolesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2003José Barluenga Abstract Bis(2-lithioallyl)amines 2, substituted at the double bonds, undergo intramolecular carbolithiation of a lithiated double bond in different solvents to afford dilithiated dihydropyrroles 3. Treatment of these dianions with electrophiles allows the preparation of functionalized pyrrole derivatives 5 and 6. Interestingly, treatment of these dianions with carboxylic esters selectively affords either keto or hydroxy compounds (9 or 10), depending on the conditions. Several experiments have been carried out in order to clarify the mechanism of this selective transformation. Finally, dilithiated dihydropyrrole 3a could be transformed in a three-step procedure into the corresponding 3,4-bis(bromomethyl) derivative 31, which can easily be converted into bicyclic pyrrole compounds 32,33 by treatment with different nucleophiles. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Palladium-Catalyzed Sequential Reactions via Allene Intermediates for the Rapid Synthesis of Fused Polycyclic Pyrrole DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Xian Huang Abstract In this paper, we report a novel sequential reaction sequence consisting of a series of processes including Sonogashira coupling, propargyl-allenyl isomerization, [3+2],cycloaddition, denitrogenation, and highly selective biradical coupling reaction, providing an efficient synthesis of fused polycyclic pyrrole derivatives. The reaction features one CC bond and two CN bonds formed to construct the pyrrole unit, together with two rings efficiently assembled in one stroke. [source] Iron(III) Salt-Catalyzed Nazarov Cyclization/Michael Addition of Pyrrole DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Masamune Fujiwara Abstract The Nazarov cyclization of two types of pyrrole derivatives was effectively catalyzed by 5,mol% alumina-supported iron(III) perchlorate [Fe(ClO4)3,Al2O3 ] which provided the desired cyclization with high trans selectivity in good to excellent yield. The cyclized product was next reacted with a vinyl ketone in the presence of the same iron salt to afford the corresponding Michael product. A sequential type Nazarov/Michael reaction of pyrrole derivatives has also been accomplished; the synthetic route to 4,5-dihydrocyclopenta[b]pyrrol-6(1,H)-one derivative 5 or 5,6-dihydrocyclopenta[b]pyrrol-4(1,H)-one derivative 6 has thus been established using a very economical iron catalyst. [source] Rhodium(I)-Catalyzed [4+1],Cycloaddition Reactions of ,,,-Unsaturated Imines with Terminal Alkynes for the Preparation of Pyrrole Derivatives,ANGEWANDTE CHEMIE, Issue 44 2009Akio Mizuno Rhodiumvinyliden-Intermediate charakterisieren die Titelreaktion (siehe Schema). Die Reaktion verläuft über die nucleophile Addition des Imin-Stickstoffatoms an den Rhodiumvinyliden-Komplex zu einem zwitterionischen Intermediat, das durch intramolekulare Cyclisierung zum Pyrrol weiterreagiert. coe: Cycloocten, Cy: Cyclohexyl. [source] ChemInform Abstract: A New Facile Approach to Isoindole and Pyrrole Derivatives.CHEMINFORM, Issue 31 2010Nasima Yasmin Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Broensted Acid-Catalyzed Nazarov Cyclization of Pyrrole Derivatives Accelerated by Microwave Irradiation.CHEMINFORM, Issue 48 2009Prabhakar Bachu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Remarkable Solvent Effect in Barton,Zard Pyrrole Synthesis: Application in an Efficient One-Step Synthesis of Pyrrole Derivatives.CHEMINFORM, Issue 46 2006Apurba Bhattacharya Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] ChemInform Abstract: One-Pot Synthesis of Pyrrole Derivatives from (E)-1,4-Diaryl-2-butene-1,4-diones.CHEMINFORM, Issue 3 2002H. Surya Prakash Rao Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Pyrrole derivatives for electrochemical coating of metallic medical devicesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2004Zehava Weiss Abstract Electropolymerization of medical devices such as cardiovascular stents may posses advantages including a simple and reproducible process with the ability to control the thickness, adherence, and composition of the coating by the duration and intensity of the applied current, the monomer composition and concentration, the solvent, and the reaction conditions. The properties of the polymer can also be controlled by copolymerization of different monomers, grafting substituents to a functionalized polymer, and by entrapping biomolecules. This article describes the synthesis of a range of pyrrole-based monomers and their electrocoating onto stainless steel surfaces. N-substituted pyrrole monomers with C1,C18 alkyl chains and poly (ethylene glycol) chains were synthesized in good yields and purity. Electropolymerization of these monomers provided uniform coatings with different hydrophobicities. Studies now focus on the incorporation of drugs in the coated device for release from the surface. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1658,1667, 2004 [source] pH-Controlled Molecular Switches and the Substrate-Directed Self-Assembly of Molecular Capsules with a Calix[4]pyrrole DerivativeCHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2008Grazia Cafeo Dr. Abstract 10,,20,-Bis(4-nitrophenyl)calix[4]pyrrole (1) forms 1:1 complexes with anions of selected aromatic hydroxy acids in which the host orientation within the guest is controlled by a change in the pH,value. Some bis-anionic guests, including those obtained from 4-hydroxybenzoic acid, 1,4- and 1,3-benzenedicarboxylic acids, induce the self-assembly of molecular capsules involving two molecules of the receptor. 1H,NMR data and solid-state structures of the 1:1 complex of 1 with p -C6H4(COOH)(COO,)+NMe4 and the 2:1 capsule [(1)2m -C6H4(COO,)2(+NMe4)2] provide structural details in solution and in the solid state. [source] Synthesis of the Antibiotic (R)-Reutericyclin via Dieckmann CondensationHELVETICA CHIMICA ACTA, Issue 11 2005Roswitha Böhme (R)-Reutericyclin ((R)- 1), a bactericidal, amphiphilic natural product with a trisubstituted tetramic acid moiety, was prepared in four steps from D -leucine in an overall yield of 24%. The chiral heterocyclic portion of 1 was synthesized by Dieckmann cyclization of ethyl N -(acetoacetyl)leucinate (7), and the resulting pyrrole derivative 8 was N -acylated with (E)-dec-2-enoyl chloride in the presence of BuLi at ,,70° (Scheme,2). This new procedure is straightforward and allows the synthesis of both antipodes of reutericyclin in an enantiomeric excess (ee) of ca. 80%. [source] Microemulsion polymerization of cationic pyrroles bearing an imidazolum-ionic liquid moietyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2009Jie Zhao Abstract A cationic pyrrole derivative, N -(4-butyl-(1-methylimidazole)) pyrrole bromide (Py-Br) bearing an imidazolium-type ionic liquid moiety was synthesized. Microemulsion polymerization of Py-Br in water/oil microemulsions produced poly(N -(4-butyl-(1-methylimidazole)) pyrrole bromide) (PPy-Br) nanoparticles. The bromide anion of the resultant PPy-Br nanoparticles was exchanged in water with different anions, including BF and PF to produce new nanoparticles bearing different counteranions. The results of thermal analysis indicate that the thermal stability of cationic PPy nanoparticles strongly depends on the nature of counteranion. As an application, water-soluble PPy-Br with fine fluorescence property was used as a new sensor for DNA detection. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 746,753, 2009 [source] Induction of potent antitumour natural-killer cells from peripheral blood of patients with advanced prostate cancerBJU INTERNATIONAL, Issue 9 2003T. Oikawa In this section there are four papers on a variety of topics. The subject of antitumour natural killer cells is addressed in patients with advanced prostate cancer. In another study, the authors describe their work into the effect of oestrogen and testosterone on the urethral seam of the developing male mouse genital tubercle. Another group of authors studied ion-channel currents of smooth muscle cells isolated from the prostate of the guinea pig, and the final paper describes how a novel pyrrole derivative, NS-8, suppresses the rat micturition reflex by inhibiting afferent pelvic nerve activity. OBJECTIVE To examine whether antitumour natural-killer (NK) cells can be induced from peripheral blood mononuclear cells (PBMCs) of patients with advanced prostate cancer, as cell therapy using antitumour immune cells is a promising candidate treatment but such patients generally have a suppressed immune response against cancer cells. PATIENTS AND METHODS PBMCs were obtained from 10 patients (four with stage D2 and six with stage B or C disease). For the NK cell expansion, PBMCs were co-cultured with irradiated HFWT cells, a cell line originating from Wilms' tumour, in RHAM , culture medium supplemented with 5% autologous plasma and interleukin-2 (200 U/mL) for 2 weeks. RESULTS When PBMCs were co-cultured with HFWT cells, lymphocytes from all patients had a 20- to 130-fold expansion after 2 weeks of culture. The CD16+ CD56+ cells constituted >,70% of the proliferated lymphocyte population. The induced NK cells had significantly greater cytotoxicity against a prostate cancer cell line (PC-3) than lymphocytes cultured with no HFWT cells. There was no significant difference in growth and phenotypes of lymphocytes and the induced NK cell activity between patients with stage D2, B or C. CONCLUSION NK cells with potent cytotoxic activity against prostate cancer cell lines from patients with advanced prostate cancer were selectively expanded. Further investigation is needed to determine whether this approach could be a candidate for cell therapy for advanced prostate cancer. [source] 2H -Pyrrole Derivatives from an Aza-Nazarov Reaction Cascade Involving Indole as the Neutral Leaving GroupEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2008Nugzar Ghavtadze Abstract Trifluoromethyl-substituted N -indolinyl-1-aza-1,4-dien-3-ones 4, which are accessible in good yields from indolinylimino esters 6 in a two-step procedure, undergo a novel type of aza-Nazarov cyclization if treated with strong acids to give the hitherto unknown 3-hydroxy-5H -pyrrole derivatives 8a,p. The solvent-free polyphosphoric acid/acyl anhydride system as the acidic reaction medium is especially efficient and requires only short reaction times. According to quantum chemical calculations the key step in the reaction cascade is the cleavage of the N,N bond of the hydrazone fragment of a protonated N -(indolin-1-yl)-1-aza-1,4-dien-3-one intermediate such as 10. This intermediate releases 3H -indole as an unusual, but very efficient neutral leaving group. Several 1-aza-1,4-dien-3-ones 4 and some 3-hydroxy-5H -pyrrole derivatives 8 were characterized by X-ray diffraction.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis of Pyrrole Derivatives through Functionalization of 3,4-Bis(lithiomethyl)dihydropyrrolesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2003José Barluenga Abstract Bis(2-lithioallyl)amines 2, substituted at the double bonds, undergo intramolecular carbolithiation of a lithiated double bond in different solvents to afford dilithiated dihydropyrroles 3. Treatment of these dianions with electrophiles allows the preparation of functionalized pyrrole derivatives 5 and 6. Interestingly, treatment of these dianions with carboxylic esters selectively affords either keto or hydroxy compounds (9 or 10), depending on the conditions. Several experiments have been carried out in order to clarify the mechanism of this selective transformation. Finally, dilithiated dihydropyrrole 3a could be transformed in a three-step procedure into the corresponding 3,4-bis(bromomethyl) derivative 31, which can easily be converted into bicyclic pyrrole compounds 32,33 by treatment with different nucleophiles. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Effect of the side chain size of 1-alkyl-pyrroles on antioxidant activity and ,Laba' garlic greeningINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2008Dan Wang Summary Previous studies showed that 1-alkyl-pyrroles not only occur in fresh food products postulated as a natural antioxidant but also might be involved in garlic greening. In the present study, a series of 1-alkyl-pyrroles with different side chain size were synthesised to study the relationship of structure and antioxidative activity and their effects on ,Laba' garlic greening. The antioxidative activity of these compounds was evaluated by the method of scavenging ABTS, and DPPH,. Results showed that increasing the size of R groups on the side chain, the antioxidative activity decreased gradually against the two radicals. The 1-alkyl-pyrroles generally exhibited stronger scavenging activities against ABTS, than DPPH,. In contrast, their corresponding amino acids except for tyrosine showed almost no antioxidative activities while pyrrole exhibited much weaker activity as compared with the 1-alkyl-pyrroles, suggesting that the 1-alkyl-pyrroles donate H-atom from pyrrole moiety rather than side chain to quench the two radicals. On the other hand, all 1-alkyl-pyrroles can turn newly harvested garlic green but to a different extent. All these results suggested that these pyrrole derivatives occurring in foodstuff played an important role in either protecting foodstuff from oxidation or acting on pigment precursors during ,Laba' garlic greening. [source] Palladium-Catalyzed Sequential Reactions via Allene Intermediates for the Rapid Synthesis of Fused Polycyclic Pyrrole DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Xian Huang Abstract In this paper, we report a novel sequential reaction sequence consisting of a series of processes including Sonogashira coupling, propargyl-allenyl isomerization, [3+2],cycloaddition, denitrogenation, and highly selective biradical coupling reaction, providing an efficient synthesis of fused polycyclic pyrrole derivatives. The reaction features one CC bond and two CN bonds formed to construct the pyrrole unit, together with two rings efficiently assembled in one stroke. [source] Iron(III) Salt-Catalyzed Nazarov Cyclization/Michael Addition of Pyrrole DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Masamune Fujiwara Abstract The Nazarov cyclization of two types of pyrrole derivatives was effectively catalyzed by 5,mol% alumina-supported iron(III) perchlorate [Fe(ClO4)3,Al2O3 ] which provided the desired cyclization with high trans selectivity in good to excellent yield. The cyclized product was next reacted with a vinyl ketone in the presence of the same iron salt to afford the corresponding Michael product. A sequential type Nazarov/Michael reaction of pyrrole derivatives has also been accomplished; the synthetic route to 4,5-dihydrocyclopenta[b]pyrrol-6(1,H)-one derivative 5 or 5,6-dihydrocyclopenta[b]pyrrol-4(1,H)-one derivative 6 has thus been established using a very economical iron catalyst. [source] An efficient synthesis of highly substituted pyrrole and bis pyrrole derivativesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2007Rajeshwar Reddy Sagyam An efficient synthesis of highly substituted pyrrole and bis pyrrole derivatives is reported. [source] Electrochemical polymerization of chiral pyrrole derivatives in electrolytes containing chiral camphor sulfonic acidPOLYMER INTERNATIONAL, Issue 10 2004GY Han Abstract N -Substituted pyrrole derivatives with chiral side groups have been synthesized and electrochemically polymerized in acetonitrile containing tetrabutylammonium perchlorate (TBAClO4) and (S)-(+)-camphor-10-sulfonic acid ((S)-(+)-CSA) or (R)-(,)-camphor-10-sulfonic acid ((R)-(,)-CSA). The resulting N -substituted polypyrrole films were characterized by cyclic voltammetry, infrared, Raman and X-ray photoelectron (XPS) spectroscopies. XPS results demonstrated that the as-grown polymer films are preferably doped by CSA anions when the monomer and the CSA anion have the same optical rotation dispersion (ORD). Furthermore, the conductivities of the polymers synthesized in the media containing CSA with the same ORD of the corresponding monomers were measured to be about 2,10 times higher than those of polymers obtained from electrolytes without CSA. Copyright © 2004 Society of Chemical Industry [source] | |||||||||||||||||||||||||