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István Kádas Gábor Szántó László Tőke AndrÁS Simon Gábor Tóth 《Journal of heterocyclic chemistry》2007,44(6):1373-1381
The 1,3‐dipolar‐cycloadditions of two kind of isoquinolinium and carbolinium ylides with fumaric and maleic nitrile resulted in pyrroloisoquinoline and indolizino[8,7‐b]indole derivatives, respectively, which are analogues of biologically active alkaloids. The cycloadditions were performed in good yield and proved to be stereoselective. The structure elucidation and complete 1H and 13C assignments have been achieved by a combination of various one‐ and two‐dimensional NMR experiments. 相似文献
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Rafael Germano Santana Derisvaldo Rosa Paiva Roberto da Silva Gomes Adriana Karla C. A. Reis 《Magnetic resonance in chemistry : MRC》2013,51(5):316-319
The complete assignment of the 1H and 13C NMR spectra of various 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamide‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamides with p‐methoxy, o‐chloro and m‐chloro substituents is reported. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Jun Ling Wei Chen Zhiquan Shen 《Journal of polymer science. Part A, Polymer chemistry》2005,43(9):1787-1796
Dihydroxyl capped biodegradable poly(DTC‐b‐PEG‐b‐DTC) (BCB) triblock copolymer and poly(TMC‐b‐DTC‐b‐PEG‐b‐DTC‐b‐TMC) (ABCBA) pentablock copolymer have been synthesized by PEG and BCB copolymer as macroinitiator in the presence of yttrium tris(2,6‐di‐tert‐butyl‐4‐methylphenolate). The copolymers without random segments have been thoroughly characterized by 1H, 13C‐NMR, SEC, and DSC. Molecular weights of the obtained copolymers are dependent on the amount of PEGs and coincide with the theoretical values. The exchange reaction of yttrium alkoxide and hydroxyl end group is essential for controlling the products' molecular weight. Their thermal behaviors are relevant to the chain lengths of PEG and PDTC segments. The Monte Carlo method has been developed to estimate the chain propagation constant and exchange reaction constant. In average, one exchange reaction will occur after approximately six monomer molecules insert into the growing chain. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1787–1796, 2005 相似文献
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Peng Wu Xiao‐Mei Liang Jian‐Jun Zhang Yue‐Mei Jia Yan‐Hong Dong Jia‐Xing Huang Fu‐Heng Chen Dao‐Quan Wang 《Helvetica chimica acta》2009,92(12):2774-2782
15‐Cyano‐12‐oxopentadecano‐15‐lactone was synthesized in 59% total yield starting from 2‐nitrocyclododecanone by Michael addition to acrylaldehyde, followed by reaction with trimethylsilylcyanide, hydrolysis, ring‐expansion, and Nef reaction. A two‐step, one‐pot synthesis of intermediate 2‐hydroxy‐4‐(1‐nitro‐2‐oxycyclododecyl)butanenitrile from 3‐(1‐nitro‐2‐oxocyclododecyl)propanal was developed and the conditions for the Nef reaction were studied. 15‐Cyano‐12‐oxopentadecano‐15‐lactam was synthesized in 40% total yield starting from 2‐nitrocyclododecanone by Michael addition to acrylaldehyde, followed by Strecker reaction, ring‐expansion, and Nef reaction. The conditions for the Strecker and Nef reactions were studied. The structures of the target compounds, intermediates, and by‐product were characterized by IR, 1H‐ and 13C‐NMR, and elemental analysis or MS. 相似文献
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Thanikasalam Kanagasabapathy Panchanatheswaran Krishnaswamy Jeyaraman Ramasubbu 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(11):o579-o582
rac‐5‐Diphenylacetyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C26H27NOS, (I), and rac‐5‐formyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C13H17NOS, (II), are both characterized by a planar configuration around the heterocyclic N atom. In contrast with the chair conformation of the parent benzothiazepine, which has no substituents at the heterocyclic N atom, the seven‐membered ring adopts a boat conformation in (I) and a conformation intermediate between boat and twist‐boat in (II). The molecules lack a symmetry plane, indicating distortions from the perfect boat or twist‐boat conformations. The supramolecular architectures are significantly different, depending in (I) on C—H...O interactions and intermolecular S...S contacts, and in (II) on a single aromatic π–π stacking interaction. 相似文献
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Syntheses and Fluorescent Properties of 6‐Methoxy‐2‐oxoquinoline‐3,4‐dicarbonitriles and 6,7‐Dimethoxy‐2‐oxoquinoline‐3,4‐dicarbonitriles 下载免费PDF全文
Guy Crépin Enoua Günther Lahm Georg Uray Wolfgang Stadlbauer 《Journal of heterocyclic chemistry》2014,51(Z1):E263-E275
4‐Chlorocarbostyrils 3 , 12 , 17 , 24 , 26 with methoxy substituents in 6, 7, or 6,7‐position react with potassium cyanide in a p‐toluenesulfinate mediated reaction either to the highly fluorescent and stable 2‐oxoquinoline‐3,4‐dicarbonitriles 6 , 27 , 29 , 30 or at slightly lower temperatures to 4‐monocarbonitriles 5 , 13 , 18 . 4‐Chlorocarbostyril 3 and lithium p‐toluenesulfinate gave pure 4‐toluenesulfonylquinolone 4 , which reacted with potassium cyanide either to monocarbonitrile 5 or dicarbonitrile 6 , depending on the reaction conditions. 4‐Trifluoromethylquinolones 9 and 19 were prepared for fluorescence comparison from the appropriate methoxyaniline and 4,4,4‐trifluoroacetoacetate. The fluorescence properties such as emission wavelengths and quantum yields of 6‐methoxyderivatives 4 , 5 , 6 , 9 , 13 were studied and compared with those of 7‐methoxy derivatives 18 , 19 and 6,7‐dimethoxyderivatives 27 , 28 , 29 , 30 . 6,7‐Dimethoxy derivatives show best results, showing long‐waved fluorescence spectra up to 520 nm and acceptable quantum yields up to 0.46 for 3,4‐dicyano derivative 27 excited at 440 nm in acetonitrile. 相似文献
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Hong Song Wei‐Bing Feng Feng Cheng De‐Qing Shi 《Journal of heterocyclic chemistry》2013,50(6):1381-1385
Two series of novel 4‐acyl‐2,5‐disubstituted‐3‐hydroxypyrazoles 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h and 4‐arylcarbonyl‐3‐substitutedisoxazol‐5‐ones 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i were synthesized by the Scotton–Baumann reaction of 2,5‐disubstituted‐2,4‐dihydro‐pyrazol‐3‐ones 1 or 3‐substituted‐4H‐isoxazol‐5‐ones 6 and various acyl chlorides, followed by the Fries rearrangement in the presence of calcium hydroxide and calcium oxide as the catalyst. Their structures were confirmed by IR, 1H NMR, mass spectroscopy, and elemental analyses. 1H NMR indicated that compounds 3 existed in enol forms and compounds 7 in keto configurations. The results of preliminary bioassays showed that some of the title compounds 3 and 7 exhibited moderate to good herbicidal activities against Brassica campestris L. at the concentration of 100 mg/L. Isoxazole compounds 7 showed better herbicidal activity against B. campestris L. than pyrazole compounds 3 did at the concentration of 100 mg/L. Moreover, most of the isoxazole compounds displayed higher herbicidal activity against B. campestris L. than Echinochloa crus‐galli. However, these compounds showed weak herbicidal activities at the concentration of 10 mg/L. 相似文献
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The title compounds, the P(3)‐axially and P(3)‐equatorially substituted cis‐ and trans‐configured 8‐benzyl‐3‐fluoro‐2,4‐dioxa‐8‐aza‐3‐phosphadecalin 3‐oxides (=8‐benzyl‐3‐fluoro‐2,4‐dioxa‐8‐aza‐3‐phosphabicyclo[4.4.0]decane 3‐oxides=2‐fluorohexahydro‐6‐(phenylmethyl)‐4H‐1,3,2‐dioxaphosphorino[5,4‐c]pyridine 2‐oxides) were prepared (ee>98%) and fully characterized (Schemes 2 and 3). The absolute configurations were established from that of their precursors, the enantiomerically pure cis‐ and trans‐1‐benzyl‐4‐hydroxypiperidine‐3‐methanols which were unambiguously assigned. Being configuratively fixed and conformationally constrained phosphorus analogues of acetyl γ‐homocholine (=3‐(acetyloxy)‐N,N,N‐trimethylpropan‐1‐aminium), they are suitable probes for the investigation of molecular interactions with acetylcholinesterase. As determined by kinetic methods, all of the compounds are weak inhibitors of the enzyme. 相似文献
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Chaza Darwich Konstantin Karaghiosoff Thomas M. Klapötke Prof. Dr. Carles Miró Sabaté 《无机化学与普通化学杂志》2008,634(1):61-68
3,4,5‐Triamino‐1,2,4‐triazolium iodide ( 1 ) was obtained in good yield and purity and characterized using vibrational (IR, Raman) and multinuclear NMR spectroscopy (1H, 13C, 15N), EA, MS, DSC, and X‐ray crystallography. The compound was synthesized by two different methods rendering two different polymorphs (α and β) as proved by X‐ray measurements, vibrational spectroscopy and DSC. 1‐Methyl‐3,4,5‐triamino‐1,2,4‐triazolium iodide ( 2 ) was synthesized by reaction of guanazine with methyliodide and fully characterized by the same techniques mentioned above. Both compounds showed to be suitable starting materials for the synthesis of guanazinium salts of energetic interest. 相似文献
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Clair Bilton Judith A. K. Howard N. N. Laxmi Madhavi Gautam R. Desiraju Frank H. Allen 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1356-1358
The title compounds, C8H10O2, (I), and C12H14O2, (II), occurred as by‐products in the controlled synthesis of a series of bis(gem‐alkynols), prepared as part of an extensive study of synthon formation in simple gem‐alkynol derivatives. The two 4‐(gem‐alkynol)‐1‐ones crystallize in space group P21/c, (I) with Z′ = 1 and (II) with Z′ = 2. Both structures are dominated by O—H?O=C hydrogen bonds, which form simple chains in the cyclohexane derivative, (I), and centrosymmetric dimers, of both symmetry‐independent molecules, in the cyclohexa‐2,5‐diene, (II). These strong synthons are further stabilized by C[triple‐bond]C—H?O=C, Cmethylene—H?O(H) and Cmethyl—H?O(H) interactions. The direct intermolecular interactions between donors and acceptors in the gem‐alkynol group, which characterize the bis(gem‐alkynol) analogues of (I) and (II), are not present in the ketone derivatives studied here. 相似文献
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Signe Vahur Anu Teearu Tõiv Haljasorg Piia Burk Ivo Leito Ivari Kaljurand 《Journal of mass spectrometry : JMS》2012,47(3):392-409
Comprehensive analysis of high‐resolution mass spectra of aged natural dammar resin obtained with Fourier transform ion cyclotron resonance mass spectrometer (FT‐ICR‐MS) using matrix‐assisted laser desorption/ionization (MALDI) and atmospheric pressure chemical ionization (APCI) is presented. Dammar resin is one of the most important components of painting varnishes. Dammar resin is a terpenoid resin (dominated by triterpenoids) with intrinsically very complex composition. This complexity further increases with aging. Ten different solvents and two‐component solvent mixtures were tested for sample preparation. The most suitable solvent mixtures for the MALDI‐FT‐ICR‐MS analysis were dichloromethane‐acetone and dichloromethane‐ethanol. The obtained MALDI‐FTMS mass spectrum contains nine clusters of peaks in the m/z range of 420–2200, and the obtained APCI‐FTMS mass spectrum contains three clusters of peaks in the m/z range of 380–910. The peaks in the clusters correspond to the oxygenated derivatives of terpenoids differing by the number of C15H24 units. The clusters, in turn, are composed of subclusters differing by the number of oxygen atoms in the molecules. Thorough analysis and identification of the components (or groups of components) by their accurate m/z ratios was carried out, and molecular formulas (elemental compositions) of all major peaks in the MALDI‐FTMS and APCI‐FTMS spectra were identified (and groups of possible isomeric compounds were proposed). In the MALDI‐FTMS and APCI‐FTMS mass spectrum, besides the oxidized C30, triterpenoids also peaks corresponding to C29 and C31 derivatives of triterpenoids (demethylated and methylated, correspondingly) were detected. MALDI and APCI are complementary ionization sources for the analysis of natural dammar resin. In the MALDI source, preferably polar (extensively oxidized) components of the resin are ionized (mostly as Na+ adducts), whereas in the APCI source, preferably nonpolar (hydrocarbon and slightly oxidized) compounds are ionized (by protonation). Either of the two ionization methods, when used alone, gives an incomplete picture of the dammar resin composition. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Ding‐Zhi‐Xiao‐Wan (DZXW) is a famous traditional Chinese medicine (TCM) formula, which is composed of four herbs, Ginseng Radix, Poria, Polygala Radix and Acori Tatarinowii Rhizoma. It has been popularly used for the treatment of emotional disease, like Alzheimer's disease, Parkinson's disease, depression, anxiety, forgetfulness and neurasthenia. In this research, a high‐performance liquid chromatography coupled with ion‐trap tandem mass spectrometry (HPLC‐IT‐MSn) method along with a high‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry (HPLC‐Q‐TOF‐MS) method in negative ion mode was established to investigate the major constitutions in DZXW. The extracts were prepared by ultra‐sonication in ethyl acetate, n‐butanol, 95% ethanol and deionized water sequentially as well as in deionized water directly. A Kromasil C18 column was used to separate the extracts of DZXW. Acetonitrile and 0.1% aqueous formic acid (V/V) were used as the mobile phase. A total of 64 components were characterized, including 16 triterpenoids, 14 Polygala saponins, 10 oligosaccharide esters, 6 sucrose esters, 2 xanthone C‐glycosides and 16 ginsenosides. 相似文献
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Shailesh K. Goswami Lyall R. Hanton C. John McAdam Stephen C. Moratti Jim Simpson 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(4):407-411
The title compounds, C11H11BrO3, (I), and C11H11NO5, (II), respectively, are derivatives of 6‐hydroxy‐5,7,8‐trimethylchroman‐2‐one substituted at the 5‐position by a Br atom in (I) and by a nitro group in (II). The pyranone rings in both molecules adopt half‐chair conformations, and intramolecular O—H...Br [in (I)] and O—H...Onitro [in (II)] hydrogen bonds affect the dispositions of the hydroxy groups. Classical intermolecular O—H...O hydrogen bonds are found in both molecules but play quite dissimilar roles in the crystal structures. In (I), O—H...O hydrogen bonds form zigzag C(9) chains of molecules along the a axis. Because of the tetragonal symmetry, similar chains also form along b. In (II), however, similar contacts involving an O atom of the nitro group form inversion dimers and generate R22(12) rings. These also result in a close intermolecular O...O contact of 2.686 (4) Å. For (I), four additional C—H...O hydrogen bonds combine with π–π stacking interactions between the benzene rings to build an extensive three‐dimensional network with molecules stacked along the c axis. The packing in (II) is much simpler and centres on the inversion dimers formed through O—H...O contacts. These dimers are stacked through additional C—H...O hydrogen bonds, and further weak C—H...O interactions generate a three‐dimensional network of dimer stacks. 相似文献
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Amritpal Kaur Avneet Pal Kaur Poonam Gautam Deepika Gautam Ram Pal Chaudhary 《Journal of heterocyclic chemistry》2019,56(8):2105-2110
Alkanediyl‐bis‐2‐aryl‐thiazolidin‐4‐one and alkanediyl‐bis‐2‐aryl‐1,3‐thiazinan‐4‐one derivatives have been congregated in a single step reaction of diaminoalkanes, aryl aldehydes, and sulfanyl acids in the presence of coupling agent N,N′‐dicyclohexylcarbodiimide under ultrasonic conditions. This method of constructing 4‐keto derivatives of thiazolidine and thiazinane is quick and clean besides yielding the products in quantitative yields. The spectral techniques corroborated the structures of the isolated products. Biological assay of the synthesized products has also been reported. 相似文献