486-25-9Relevant articles and documents
Fulvalene Derivatives Containing a Tetrabenzofluorene Unit: New Nonplanar Fulvalenes with High Electron Affinity
Yamada, Kenta,Shibamoto, Hiroshi,Tanigawa, Yusuke,Ishikawa, Hiroyuki,Nishida, Jun-Ichi,Kitamura, Chitoshi,Kurata, Hiroyuki,Kawase, Takeshi
, p. 2085 - 2090 (2016)
17H-Tetrabenzo[a,c,g,i]fluoren-17-one possessing a nonplanar, helicene-like structure was efficiently prepared by aerial oxidation of 17H-tetrabenzo[a,c,g,i]fluorene under mild basic conditions. A quinone methide and an unsymmetrical fulvalene containing a tetrabenzofluorene unit were synthesized from the ketone. Treatment of 17-bromotetrabenzo[a,c,g,i]fluorene with a base afforded a symmetric fulvalene as an air-sensitive blue solid. Electrochemical analyses revealed that these compounds have high electron affinities.
A novel method for monitoring the transesterification reaction of oil in biodiesel production by estimation of glycerol
Reddy, Sabbasani Rajasekhara,Titu, Devamani,Chadha, Anju
, p. 747 - 754 (2010)
A quantitative method is reported for the estimation of glycerol during transesterification of oil to form biodiesel. The reagent used to derivatize glycerol was 9,9-dimethoxyfluorene. Glycerol is estimated by both UV-visible spectrophotometric and high performance liquid chromatography methods. Using the former method, detection limits of 0.05% w/w of glycerol in biodiesel was established. Validation of the developed method was done using the Greenhill method for determination of free glycerol formed during the transesterification reaction.
Chromium-assisted oxidations with sodium perborate by phase transfer catalysis
Muzart,N'Ait Ajjou
, p. 575 - 580 (1991)
Oxidation by sodium perborate of selected alcohols and unsaturated compounds to ketones and acids was achieved at 60-80°C in the presence of catalytic amounts of chromium(VI) oxide and methyltridecylammonium chloride.
Synthesis of fluorovinyl pyrazolyl (thio)ethers by the reaction of gem-difluoroalkenes with pyrazolin-5-ones (thiones)
Huang, Tao,Zhao, Xianghu,Ji, Xinfei,Wu, Wei,Cao, Song
, p. 61 - 68 (2016)
A mild and efficient method for the preparation of fluorovinyl pyrazolyl ethers and thioethers by the reaction of gem-difluoroalkenes having aryl substituents with pyrazolin-5-ones and pyrazolin-5-thiones, respectively, in the presence of t-BuOK is described.
Retro Abramov vs. Rearrangement path competition in hydroxyphosphonate decomposition
Gancarz, Roman,Gancarz, Irena,Deron, Agnieszka
, p. 61 - 69 (2000)
1-hydoxyphosphonates in the presence of aliphatic amine undergo two competitive processes: retro Abramov reaction and intramolecular hydroxyphosphonate-phosphate rearrangement. Both reaction rates and their ratio strongly depend on the nature of the substituent on a alpha carbon atom. Kinetic experiments indicate that two reactions proceed via common transition state.
Ruthenium-catalyzed cytochrome P-450 type oxidation of alkanes with alkyl hydroperoxides
Murahashi,Oda,Naota,Kuwabara
, p. 1299 - 1302 (1993)
The ruthenium-catalyzed oxidation of alkanes with t-butyl hydroperoxide under mild conditions gives the corresponding ketones and alcohols highly efficiently. Kinetic study revealed that the reaction involves hydrogen abstraction of oxoruthenium species.
Tetracyclic arenes by benzannulation of tricyclic carbene complexes of chromium with alkynes: Chemo-, regio-, and stereoselectivity
Pfeiffer, Juergen,Nieger, Martin,Doetz, Karl Heinz
, p. 1843 - 1857 (1998)
The tricarbonyl chromium complexes 7-9 and the tetracyclic arenes 11-13 were synthesized from 1-hexyne and the tricyclic chromium carbene complexes 3-5, which are derived from diazo precursors. The nonplanar dibenzocycloheptenylidene complex 4 afforded the benzannulation product S(p)M(h)/R(p)P(h)-8 stereoselectively, as established by NMR spectra and an X-ray crystal structure analysis. The benzannulation failed with the carbene complexes 1 and 2, presumably due to their reduced propensity for decarbonylation. Upon reaction with 1-hexyne, carbene complex 21, bearing two electronically different arene substituents, revealed only a low regioselectivity (1.6:1) in favour of chromium complex 22, which results from the annulation of the less electron-rich arene ring.
Substituent and pH Effects on the Hydrolysis Modes of 9-(dinitromethyl)-9-alkoxylfluorenes
Hoz, Shmaryahu,Perach, Sara Sima
, p. 4056 - 4059 (1982)
The hydrolysis of 9-(dinitromethyl)-9-alkoxyfluorene was studied in aqueous solution over the pH range 3-12.Under acidic conditions, the reactions proceed via the fluorenyl oxocarbonium ion in analogy with ketal hydrolysis reactions.Rate constants for the neutral adducts decrease in the order 2-Pr > 2-Et > 2-Me >> 2-Tf.This order of reactivity indicates that substituent electronic effects dominate, whereas steric affects are only of secondary importance.Comparison with literature data for ketal hydrolysis reactions indicates the general validity of this conclusion for the above class of reactions.Out of the four substrates only 2-Tf undergoes hydrolysis under basis conditions by an E1cB mechanism.The other three adducts are practically inert under basic conditions (pH>9).The pKa's of the four substrates range from 6.3 to 6.7, indicating again a small or constant sensitivity to the steric size of the substituent.
On the mechanism of the directed ortho and remote metalation reactions of N,N-dialkylbiphenyl 2-carboxamides
Tilly, David,Fu, Jian-Min,Zhao, Bao-Ping,Alessi, Manlio,Castanet, Anne-Sophie,Snieckus, Victor,Mortier, Jacques
, p. 68 - 71 (2010)
"Chemical Equation Presented" A study concerning the mechanism of the LDA-mediated ortho and remote metalation of N,N-dialkyl-2-biphenyl carboxamides (e.g., 4a) is reported. On the basis of site-selective lithiation/electrophile quench experiments, including deuteration, the LDA metalation of 4 is proposed to involve initial amide-base complexation (CIPE) and equilibrium formation of 5, whose fast reaction with an in situ electrophile (TMSCI) to afford 6 prevents its equilibration with 7. In the absence of an electrophile,5 undergoes equilibration via 4a with 7, whose fate is instantaneous cyclization to a stable tetrahedral carbinolamine oxide 8 which, only upon hydrolysis, affords fluorenone (3).
C-OH bond cleavage initiated by electron transfer: Electroreduction of 9-fluorenol
Mendkovich, Andrey S.,Syroeshkin, Mikhail A.,Nasybullina, Darya V.,Mikhailov, Mikhail N.,Gultyai, Vadim P.,Elinson, Mikhail N.,Rusakov, Alexander I.
, p. 962 - 973 (2016)
Cyclic voltammetry, chronoamperometry, coulometry, electrolysis, digital simulation, quantum chemical calculations of 9-fluorenol as an example, were used to show that the electroreduction of aryl derivatives of methanol in 0.1 M Bu4NClO4/DMF proceeds via the ECE mechanism (including the stages of radical anion formation and the C-OH bond cleavage in the radical anion) complicated by the reactions of the depolarizer with the anionic products. Among these reactions are the deprotonation of 9-fluorenol and its monoanions by hydroxide anion and fluorenyl anion. The thermodynamic parameters of the reactions have been estimated both theoretically and experimentally. It was found that the equilibrium constants of the fluorenyl anions deprotonation are close (C-anion) or higher (O-anion) than that of fluorenol. As a result the total equilibrium is shifted towards the side of the dianion of 9-fluorenone. The unusual ratio of the equilibrium constants was explained by lower basicity of π?-dianion compare with other anions.
