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XiaoXiaWANG YongMinZHANG 《中国化学快报》2002,13(6):499-500
The α,β vicinal dibrome carboxylic acid and its derivatives were debrominated with Sm/HOAc system to afford the corresponding cinnamic acid and its derivatives in good yields under mild conditions. 相似文献
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Acetonitrile and [D3]acetonitrile in the vicinal region of a planar AgX fiber contain linear dipole–dipole linked oligomers as shown by 1) comparison of infrared band intensity ratios in the gaseous and condensed phases and 2) remarkable plots of absorbance (C? N stretch) versus time during evaporation from an AgX planar fiber element. The plots (CH3CN 2252 cm?1, CD3CN 2262 cm?1) reveal the presence of octamers, hexamers, tetramers, and dimers along with some heptamer, trimer, and monomer structures. A novel isotope effect arises from the somewhat smaller size of the CD3CN resulting in an increase in the CN band intensity. The organized oligomers may be termed pseudocrystals and are the main components responsible for absorption intensity in the infrared spectrum of acetonitrile, on the AgX planar fiber or in an IR cell. 相似文献
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B. I. Ugrak Yu. A. Manaev V. P. Perevalov S. A. Shevelev 《Russian Chemical Bulletin》1992,41(11):2012-2017
The15N NMR chemical shifts and15N-1H SSCCs are presented for substituted N-methylpyrazoles with substituents such as CH3, NO2, Br, Cl, NH2, O=CNH2, O=CPh, and COOH at the carbon atoms. The15N chemical shifts of the cyclic atoms of nitrogen and the nitro groups are discussed as well as the geminal and vicinal SSCCs of the ring nitrogen atoms with the hydrogen atoms of the CH and CH3 fragments.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117334 Moscow. D. I. Mendeleev Chemico-Technological Institute, Moscow, Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2554–2561, November, 1992. 相似文献
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Katritzky AR Akhmedov NG Abdel-Fattah AA Wang M Rostek CJ Maender OW 《Magnetic resonance in chemistry : MRC》2004,42(5):424-435
Nucleophilic addition of alkyl- and benzylthiols to benzoquinone diimine (1) gave the corresponding 3-alkylthio- or 3-benzylthio-1,4-phenylenediamines (2-5). However, addition of aryl- or heteroarylthiols to 1 formed 2-arylthio- or 2-heteroarylthio-1,4-phenylenediamines (6-14). The structures of 2-14, obtained in 55-91% yields, were confirmed in CDCl3 or DMSO-d6 solution using 1D (NOE difference, coupled 13C NMR spectra, APT and DEPT) and 2D NMR techniques [DQCOSY, NOESY, HETCOR and heteronuclear multiple bond coherence (HMBC)] that resulted in unambiguous proton and carbon NMR resonance assignments. The substituent-induced 13C NMR chemical shift differences were calculated in 2-14 relative to carbon atoms in the model compound N1-(1,3-dimethylbutyl)-N4-phenyl-1,4-phenylenediamine (DMBPPD) (15) (a reduced form of benzoquinone diimine). 相似文献
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Takehito Dei Kazuhide Morino Atsushi Sudo Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2012,50(13):2619-2625
Novel copolymers composed of a styrene (St) derivative bearing a vicinal tricarbonyl moiety and various vinyl monomers such as St, methyl methacrylate (MMA), and N‐vinylpyrrolidone (NVP) were synthesized by (1) radical copolymerization of a St derivative with a 1,3‐diketone structure with St, MMA, and NVP and (2) successive oxidation of the resulting copolymers with N‐bromosuccinimide in DMSO to convert their 1,3‐diketone moieties in the side chains into the corresponding vicinal tricarbonyl moieties. Their tricarbonyl moieties were readily hydrated in water‐containing acetone to generate the corresponding copolymers bearing geminal diol structures in the side chains. On the other hand, heating the resulting copolymers bearing the geminal diol structures in vacuo‐enabled successful recovery of the vicinal tricarbonyl moieties to demonstrate the reversible nature of this system. The hydration behavior in powdery state under air atmosphere saturated by water was also investigated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
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Andrej Jancarik Gaspard Levet André Gourdon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(9):2366-2374
The field of long acenes, the narrowest of the zig-zag graphene nanoribbons, has been an area of significant interest in the past decade because of its potential applications in organic electronics, spintronics and plasmonics. However the low solubility and high reactivity of these compounds has so far hindered their preparation on large scales. We report here a concise strategy for the synthesis of higher acenes through Diels–Alder condensation of arynes with a protected tetraene ketone. After deprotection by cleavage of the ketal, the obtained monoketone precursors cleanly yield the corresponding acenes through quantitative cheletropic thermal decarbonylation in the solid state, at moderate temperatures of 155 to 205 °C. This approach allows the preparation of heptacene, benzo[a]hexacene, cis- and trans-dibenzopentacene and offers a valuable new method for the synthesis of even larger acenes. 相似文献