25074-67-3Relevant academic research and scientific papers
Copper-Catalyzed One-Pot Synthesis of Dibenzofurans, Xanthenes, and Xanthones from Cyclic Diphenyl Iodoniums
Zhu, Daqian,Li, Min,Wu, Zhouming,Du, Yongliang,Luo, Bingling,Huang, Peng,Wen, Shijun
supporting information, p. 4566 - 4571 (2019/07/09)
Oxygenation of cyclic diphenyl iodoniums (CDPIs) with varied medium-ring sizes has been fully investigated. This practical copper-catalyzed tandem reaction of CDPIs with water as the oxygen source enables the construction of derivatised dibenzofurans and xanthenes at moderate to good yields. Moreover, structurally important xanthones are also successfully accessed under the oxygenation conditions with additional TEMPO.
Synthesis process of dibenzofuran derivatives
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Paragraph 0032; 0033, (2018/09/26)
The invention relates to a synthesis process of dibenzofuran derivatives, and relates to the fields of natural products with biological activity, medicaments and material chemistry. The used raw material is a cyclic diphenyliodonium trifluoromethanesulfonate derivative, a reaction is carried out in a water phase at 100 DEG C under the catalysis of a 1,10-phenanthroline ligand and cuprous iodide, and a series of dibenzofuran derivatives are obtained. With the adoption of the method provided by the invention, the dibenzofuran derivatives can be obtained by carrying out the reaction at the temperature of 100 DEG C for 24 hours, and the yield is 60-96%. In the reaction, water is taken as a reagent as well as a solvent for participating in the reaction, and the simple, convenient, green, economic, and novel method is provided for synthesizing the derivatives.
Reaction Mechanism of 4-Chlorobiphenyl and the NO3 Radical: An Experimental and Theoretical Study
Shi, Jin,Bi, Wenlong,Li, Shenmin,Dong, Wenbo,Chen, Jianmin
, p. 3461 - 3468 (2017/06/09)
Experiment and theoretical chemistry calculations were conducted to elucidate the mechanism of the reaction between 4-chlorobiphenyl (4-CB) and the NO3 radical. The degradation of PCBs was investigated mechanistically through transient absorption spectroscopy technology and high-accuracy theoretical calculation by using 4-CB as the model. Laser flash photolysis (LFP) experiments were performed at 355 nm. The main intermediate was analyzed through transient absorption spectroscopy and identified to be a charge transfer complex (CTC). The final products were identified through GC-MS analysis. The ground states and excited states of the reactants were calculated through density functional theory (DFT) method. The absorption bands at 400 and 700 nm show good agreement with the experimental results. The ratio of absorbance at 400 and 700 nm is 1.6, and the experimental value is 1.8. Analysis of the charge population indicated that one unit charge transfer from 4-CB to NO3. The entire reaction process was divided into two phases. In the first phase, the CTC intermediate was formed by electrostatic attraction between 4-CB and the NO3 radical. In the second phase, the most important channel of subsequent reactions is the σ-complex as an intermediate formed by N-C coupling. The final product 4-chloro,2-nitrobiphenyl was generated with the breakage of BC-H and BN-O, and benzene derivatives were formed by other channels.
Rhodium-catalyzed decarbonylative C-H arylation of 2-aryloxybenzoic acids leading to dibenzofuran derivatives
Maetani, Shinji,Fukuyama, Takahide,Ryu, Ilhyong
supporting information, p. 2754 - 2757 (2013/07/19)
Rhodium-catalyzed intramolecular C-H arylation of 2-aryloxybenzoic acids proceeded accompanied by decarbonylation to give dibenzofuran derivatives in high yields. The present reaction is widely applicable to substrates bearing various functionalities.
Oxidative cyclization of 2-arylphenols to dibenzofurans under Pd(II)/peroxybenzoate catalysis
Wei, Ye,Yoshikai, Naohiko
, p. 5504 - 5507 (2011/12/05)
2-Arylphenols undergo intramolecular C-H bond activation/C-O bond formation to afford dibenzofuran derivatives under palladium catalysis in the presence of tert-butyl peroxybenzoate as an oxidant. Kinetic isotope effect experiments indicated that C-H bond cleavage is the rate-limiting step of the reaction.
Synthesis of dibenzofurans via palladium-catalyzed phenol-directed C-H activation/C-O cyclization
Xiao, Bin,Gong, Tian-Jun,Liu, Zhao-Jing,Liu, Jing-Hui,Luo, Dong-Fen,Xu, Jun,Liu, Lei
supporting information; experimental part, p. 9250 - 9253 (2011/08/06)
A practical, Pd(0)/Pd(II)-catalyzed reaction was developed for phenol-directed C-H activation/C-O cyclization using air as an oxidant. The turnover-limiting step of the process was found to be C-O reductive elimination instead of C-H activation. This reaction can tolerate a variety of functional groups and is complementary to the previous methods for the synthesis of substituted dibenzofurans.
Prediction of polychlorinated dibenzofuran congener distribution from gas-phase phenol condensation pathways
Ryu, Jae-Yong,Mulholland, James A.,Oh, Jeong-Eun,Nakahata, Duane T.,Kim, Do-Hyong
, p. 1447 - 1455 (2007/10/03)
A model for predicting the distribution of dibenzofuran and polychlorinated dibenzofuran (PCDF) congeners from a distribution of phenols was developed. The model is based on a simplified chemical mechanism. Relative rate constants and reaction order with respect to phenol precursors were derived from experimental results using single phenols and equal molar mixtures of up to four phenols. For validation, experiments were performed at three temperatures using a distribution of phenol and 19 chlorinated phenols as measured in municipal waste incinerator exhaust gas. Comparison of experimental measurements and model predictions for PCDF isomer distributions and homologue pattern shows agreement within measurement uncertainty. The R-squared correlation coefficient exceeds 0.9 for all PCDF isomer distributions and the distribution of PCDF homologues. These results demonstrate that the distribution of dibenzofuran and the 135 PCDF congeners from gas-phase condensation of phenol and chlorinated phenols can be predicted from measurement of the distribution of phenol and the 19 chlorinated phenol congeners.
Identification of surrogate compounds for the emission of PCDD/F (I-TEQ value) and evaluation of their on-line realtime detectability in flue gases of waste incineration plants by REMPI-TOFMS mass spectrometry
Blumenstock,Zimmermann,Schramm,Kettrup
, p. 507 - 518 (2007/10/03)
Correlations between products of incomplete combustion (PIC), e.g., chloroaromatic compounds, can be used to characterise the emissions from combustion processes, like municipal or hazardous waste incineration. A possible application of such relationships may be the on-line real-time monitoring of a characteristic surrogate, e.g., with Resonance-Enhanced Multiphoton Ionization-Time-of-Flight Mass Spectrometry (REMPI-TOFMS). In this paper, we report the relationships of homologues and individual congeners of chlorinated benzenes (PCBz), dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and phenols (PCPh) to the International Toxicity Equivalent (I-TEQ) of the PCDD/F (I-TEQ value) in the flue gas and stack gas of a 22 MW hazardous waste incinerator (HWI). As the REMPI detection sensitivity is decreasing with the increase of the degree of chlorination, this study focuses on the lower chlorinated species of the compounds mentioned above. Lower chlorinated species, e.g., chlorobenzene (MCBz), 1,4-dichlorobenzene, 2,4,6-trichlorodibenzofuran or 2,4-dichlorophenol, were identified as I-TEQ surrogates in the flue gas. In contrast to the higher chlorinated phenols, the lower chlorinated phenols (degree of chlorination 4) were not reliable as surrogates in the stack gas. The identified surrogates are evaluated in terms of their detectability by REMPI-TOFMS laser mass spectrometry. The outcome is that MCBz is the best suited surrogate for (indirect) on-line measuring of the I-TEQ value in the flue gas by REMPI-TOFMS. The correlation coefficient r of the MCBz concentration to the I-TEQ in the flue gas was 0.85.
Electroreduction of 2- and 3-Chlorodibenzofuran in Deuterated Methanol
Voss, Juergen,Waller, Edgar,Kraenke, Petra
, p. 430 - 436 (2007/10/03)
The cathodic reduction of dibenzofuran (2), 2-chlorodibenzofuran (4), and 3-chlorodibenzofuran (1) in deuterated methanol is investigated. The Birch-type reduction product 1,4-dibenzofuran (3) is formed from 1 via 2, whereas 2-chloro-1,4-dihydrodibenzofuran (5) is obtained as by-product besides 3 from 4 as starting compound. Deuterium is only incorporated into the reduction products if CH3OD or CD3OD but not if CD3OH are used. This observation is strongly indicative of a polar mechanism involving protonation rather than a radical mechanism with hydrogen atom abstraction to be operative.
A Short Synthesis of Dibenzofurans and Dibenzothiophenes
Black, Michael,Cadogan, J. I. G.,McNab, Hamish
, p. 395 - 396 (2007/10/02)
An afficient synthesis of dibenzofurans and dibenzothiophenes from aryl salicylates is described, which involves a novel rearrangement-extrusion-cyclisation sequence of o-substituted phenoxyl and thiophenoxyl radicals.
