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D. A. Kisun'ko M. V. Zabalov Yu. F. Oprunenko D. A. Lemenovskii 《Russian Journal of General Chemistry》2004,74(1):105-109
Unlike isoelectronic 6-indenyl ruthenium, manganese, and chromium complexes, heating of Mn(CO)5OTf, [Ru(Cp*)Cl4], and Cr(C10H8)(CO)3 with isomeric 2-ethyl-5-methylcyclopenta[b]thiophenes leads to the corresponding 5-complexes where the metal is coordinated at the C5-carbocycle. The structure of the complex Mn(Th)(CO)3 (Th = 2-ethyl-5-methylcyclopenta[b]thienyl) was proved by X-ray analysis. 相似文献
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A convenient procedure for the synthesis of 2‐spirobenzopyranoquinone 5 and its application to the preparation of spironaphtho[2,3‐b]pyranoquinones 6 and 7 is described. 相似文献
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Sonali Verma Barkha Srivastava Kusum Sharma Rahul Joshi Pushpa Pardasani R. T. Pardasani 《Research on Chemical Intermediates》2012,38(3-5):723-731
[4?+?2]-Photocycloadditions of benzo[b]thiophene-2,3-dione with electron-rich and electron-deficient alkenes have been described. Olefins preferentially add at both carbonyl groups to give the head-to-head [4?+?2] cycloadducts, i.e., dioxanes only. Comprehensive molecular orbital calculations at DFT-B3LYP level have been carried out to address the mechanism as well as regiochemical course of the reaction. 相似文献
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The development of novel synthons and efficient methods to synthesize chiral polycyclic indoles has been a hot topic in organic synthesis and medicinal chemistry owing to their broad applications in medicines,pesticides,and other functional molecules.Here,we disclosed novel indolyl substituted metal-allyl zwitterionic intermediates through the decarboxylation of conveniently available vinyl indoloxazolidones,which could be regarded as two types of dipolar species through the anionic delocalization.The palladium-π-allyl species tended to serve as an all-carbon 1,3-dipole in the asymmetric[3+2]cycloaddition with electrondeficient alkenes,which furnished polysubstituted cyclopenta[b]indoles with high regio-and stereoselectivities.Meanwhile,the iridium-π-allyl species was recognized as an aza-1,3-dipole in asymmetric[3+2]cycloaddition with in situ generated C1 ammonium enolates,affording pyrrolo[1,2-α]indoles with high diastereo-and enantioselectivities.In addition,the dipolar cycloadditions could be easily scaled-up and several synthetic transformations of the cycloadducts were demonstrated for the rapid synthesis of diverse chiral polycyclic indoles. 相似文献
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In modem organic chemical research, 4H-benzo-[b]-pyran and their derivatives have attracted strong interest due to their useful biological and pharmacological properties. Herein, we report a clean one-pot synthesis of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo-4H-5,6,7,8-tetrahydro-benzo-[b]-pyrans from aromatic aldehyde, malononitrile and 5,5-dimethyl-1,3-cyclohexadione using hexadecyl trimethyl ammonium bromide (HTMAB) as the catalyst. This method provides several advantages such as high yield, simple work-up procedure and environmental friendliness. All the products were characterized by 1H NMR and IR analyses. 相似文献
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《合成通讯》2013,43(23):4359-4367
Abstract Reaction of 5‐amino‐3‐substituted pyrazoles (1a–c) and 5‐amino‐1,3‐disubstituted pyrazoles (1d–i) with fluorinated‐β‐diketones (2) results in the formation of the single isomer of pyrazolo[3,4‐b]pyridines (4a–h). A one‐pot procedure for the synthesis of title compounds starting from α‐cyanoacetophenones along with a possible mechanistic pathway for the formation of the title compounds is described. 相似文献
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Different novel phthalazino[2,3‐b]phthalazine‐5,7,12,14‐tetraones were synthesized in a simple and environmentally benign method from the reaction of phthalic anhydrides with semicarbazide or thiosemicarbazide using montmorillonite K‐10 clay as solid heterogeneous acidic catalyst and microwaves under solvent‐free conditions in good yields and short reaction times. Products were characterized by the elemental analysis, IR, NMR, and mass spectrometry. 相似文献
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In this paper, a fully regiocontrolled synthesis of either 2- and 3-substituted benzo[b]furans is described. Direct reaction between phenols and α-bromoacetophenones in the presence of neutral alumina yields 2-substituted benzo[b]furans with complete regiocontrol. When a basic salt such as potassium carbonate is used, the corresponding 2-oxoether is obtained. Cyclization of these latter compounds promoted by neutral alumina yields the corresponding 3-substituted benzo[b]furans. Using the former method, Moracin M and other analogues can be obtained from commercial sources in two preparative steps. DFT calculations provide reasonable reaction paths to understand the formation of 2-substituted benzo[b]furans. 相似文献
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Sergey I. Kovalenko Oksana V. Krivoshey Svetlana V. Shishkina Oleg V. Shishkin 《合成通讯》2013,43(21):3719-3727
4‐Hydrazinoquinazoline was found to form new 2‐(3,4‐dihydro‐3oxo‐2H‐[1,2,4]triazino[4,3‐c]quinazolin‐4‐yl)acetic acid with maleic anhydride in on‐step sequence. Proposed heterocyclization includes, probably, acylation reaction followed by intramolecular uncleophilic addition. 相似文献
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Xue Fei Yang Ling Yi Kong 《中国化学快报》2007,18(4):380-382
A series of 2-aryl-5-alkyl-7-methoxylbenzo[b]furan derivatives have been synthesized by utilizing the coupling of methyl 3-methoxy-4-hydroxy-5-bromocinnamate with cuprous phenylacetylide as the key step.The structures of the new compounds were confirmed by1H NMR,IR and MS.The structure of compound 14 was further confirmed by single crystal X-ray.Compound 17 showed cytotoxic activity against human lung carcinoma A549. 相似文献
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Experimentally observed changes in the electronic absorption spectrum of sodium salt of synthetic polyadenyl–polyuridyl acid (Poly[A]·Poly[U]) in the aqueous solution (pH = 7.0, I = 0.15 mol/L) with the change in temperature were explained in terms of co-existence of two different forms of the Poly[A]·Poly[U] strands. Chemometrics analysis of full set of melting curves measured at 120 wavelengths in the UV spectral range has been performed using evolving factor analysis (EFA) and KALS designed for the calculation of equilibrium constants from spectrometry data without a priori set model of the system. Using the Van’t Hoff equation, we have determined thermodynamic constants of the biopolymer transition from the double stranded helix into the random coil conformation (helix–coil transition), they can be further used to quantify the possibility of these structures to be involved in biochemical processes. Molecular model of partially denatured Poly[A]′·Poly[U]′ complex has been biult by means of molecular mechanics. 相似文献
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Substituents in the 3 and 6-positions of benzo[b]-1,4-diazabicyclo[2.2.2]octane are capable of influencing the reactivity of the nitrogen atoms in the hydroxyethylation reaction due to steric hindrances or anchimeric contribution. Depending on the reaction conditions and substituents in the aromatic ring of benzo[b]-1,4-diazabicyclo[2.2]octane, either mono- or bis-quaternary salts were obtained.For Communication 24, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 215–218, February, 1992. 相似文献
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A method for the synthesis of 2-substituted 6,8-dinitro[1,2,4]triazolo[1,5-a]pyridines is proposed. The method includes the reaction of 2-chloro-3,5-dinitropyridine with the corresponding 5-substituted
tetrazoles. The resulting compounds react with anhydro bases of α- and γ-methylazinium salts to give zwitterionic σ-adducts.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1405–1407, July, 1999. 相似文献
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α‐Tosyloxyketones (2), readily accessible through hypervalent iodine oxidation of enolizable ketones (1) using [hydroxy(tosyloxy)iodo]benzene (HTIB) in acetonitrile, exclusively generates the 6‐arylimidazo[2,1‐b]thiazoles (4) on treatment with commercially available 2‐aminothiazole (3). 相似文献
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Various 4H-benzo[b]pyran derivatives were synthesized via a one-pot three-component condensation of arylaldehyde, malononitrile and dimedone in water using β-cyclodextrin (β-CD) as an efficient catalyst. This method provides several advantages, including mild reaction conditions, operational simplicity, high yields and minimal pollution of the environment. 相似文献
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WANG Yan-xia YE Song 《高等学校化学研究》2006,22(4):520-523
IntroductionPhotochemical reactions, which involve a three-membered ring, have been of great interest to experi-mental photochemists[1—10]. A main reason for thisphenomenon is that the cyclopropane ring exhibits somereaction characteristics of double bon… 相似文献
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Roman A. Irgashev Nadezhda S. Demina Nikita A. Kazin Gennady L. Rusinov 《Tetrahedron letters》2019,60(16):1135-1138
Two new classes of heteroacenes, namely benzo[4′,5′]thieno[2′,3′:4,5]thieno[3,2-b]quinolines and benzo[4′,5′]thieno[2′,3′:4,5]thieno[3,2-b][1,8]naphthyridines, have been formed using the Friedländer reaction to annulate the benzo[b]thieno[2,3-d]thiophene scaffold to quinoline or 1,8-naphthyridine fragments. In accordance with this synthetic strategy, benzo[b]thieno[2,3-d]thiophen-3(2H)-ones were treated with 2-aminobenzaldehydes or 2-aminonicotinaldehyde in the presence of pyrrolidine in glacial acetic acid at reflux to give the desired quinoline- or 1,8-naphthyridine-fused compounds, respectively. The optical and electrochemical properties of selected heteroacenes were determined. 相似文献