79249-48-2Relevant academic research and scientific papers
A classical but new kinetic equation for hydride transfer reactions
Zhu, Xiao-Qing,Deng, Fei-Huang,Yang, Jin-Dong,Li, Xiu-Tao,Chen, Qiang,Lei, Nan-Ping,Meng, Fan-Kun,Zhao, Xiao-Peng,Han, Su-Hui,Hao, Er-Jun,Mu, Yuan-Yuan
, p. 6071 - 6089 (2013/09/12)
A classical but new kinetic equation to estimate activation energies of various hydride transfer reactions was developed according to transition state theory using the Morse-type free energy curves of hydride donors to release a hydride anion and hydride acceptors to capture a hydride anion and by which the activation energies of 187 typical hydride self-exchange reactions and more than thirty thousand hydride cross transfer reactions in acetonitrile were safely estimated in this work. Since the development of the kinetic equation is only on the basis of the related chemical bond changes of the hydride transfer reactants, the kinetic equation should be also suitable for proton transfer reactions, hydrogen atom transfer reactions and all the other chemical reactions involved with breaking and formation of chemical bonds. One of the most important contributions of this work is to have achieved the perfect unity of the kinetic equation and thermodynamic equation for hydride transfer reactions. The Royal Society of Chemistry.
Reaction of electronically stabilized thiones with benzyne. The isolation of thiobenzophenone-benzyne and thiopivalophenone-benzyne adducts
Okuma, Kentaro,Shiki, Kyoko,Sonoda, Shinya,Koga, Yuji,Shioji, Kosei,Kitamura, Tsugio,Fujiwara, Yuzo,Yokomori, Yoshinobu
, p. 155 - 161 (2007/10/03)
The reaction of thiobenzophenones (1) with phenyl[2- (trimethylsilyl)phenyl]iodonium trifluoromethanesulfonate (4) in the presence of tetrabutylammonium fluoride afforded the corresponding [4+2] cycloadducts, which are the first examples of thiobenzophenone-benzyne adducts. The reaction of thiopivalophenone (6) with benzyne prepared from 4 and tetrabutylammonium fluoride at room temperature gave [2+2] cycloadducts (7). When the reaction was carried out in refluxing dichloromethane, a mixture of 7 and [4+2] cycloadducts (13) was obtained.
Reaction of thiobenzophenones with benzyne
Okuma, Kentaro,Yamamoto, Toshiro,Shirokawa, Takafumi,Kitamura, Tsugio,Fujiwara, Yuzo
, p. 331 - 332 (2007/10/03)
Reaction of thiobenzophenones with phenyl[2-(trimethylsilyl)-phenyl]iodonium trifluoromethanesulfonate in the presence of tetrabutylammonium fluoride afforded the corresponding adducts, which are the first examples of benzyne-thiobenzophenone adducts.
The first isolation of benzyne-thiobenzophenone adducts
Okuma, Kentaro,Yamamoto, Toshiro,Shirokawa, Takafumi,Kitamura, Tsugio,Fujiwara, Yuzo
, p. 8883 - 8886 (2007/10/03)
Reaction of thiobenzophenones with phenyl[2-(trimethylsilyl)phenyl]iodonium trifluoromethanesulfonate in the presence of tetrabutylammonium fluoride afforded the corresponding adducts, which are the first examples of benzyne-thiobenzophenone adducts. Copyright (C) 1996 Elsevier Science Ltd.
Preparations of 6-Substituted 6H-Dibenzo-thiopyrans and Their S-Oxides Through Nucleophilic Additions to 6H-Dibenzothiopyran-6-one
Ridley, Damon D.,Smal, Mary A.
, p. 795 - 802 (2007/10/02)
Methods for the preparations of 6-substituted 6H-dibenzothiopyrans and the corresponding S-oxides were explored.The most general procedure involved the addition of Grignard reagents to 6H-dibenzothiopyran-6-one, whereupon 6-substituted 6H-dibenzothiopyran-6-ols were formed.The carbonyl group in the thioester thus behaved like an isolated ketone in its reactions with nucleophiles.The resultant dibenzothiopyran-6-ols were acid-labile, and dehydration products underwent further modification in some instances.Oxidation of the olefins afforded stable S-oxides.The dianion formed by reduction of dibenzothiophen also offered routes to 6-substituted 6H-dibenzothiopyrans, but the reactions of this dianion were non-regioselective and thus were of limited use.
Ylide Formation and Rearrangement in the Thermal Reaction of 6H-Dibenzothiopyran and its 6-Phenyl Derivative with Diazoalkanes
Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
, p. 917 - 922 (2007/10/02)
Reaction of 6-phenyl-6H-dibenzothiopyran (1b) with diphenyldiazomethane (2a) in refluxing benzene affords 6,6,7-triphenyl-6,7-dihydrodibenzothiepin (3b) as major product, together with minor amounts of 6-diphenylmethyl-6-phenyl-6H-dibenzothiopyran (4b).Analogous results are obtained from the reaction of 6H-dibenzothiopyran (1a); however, in this case the yields of the corresponding ring-expansion and insertion products (3a) and (4a) are similar.Copper(II) sulphate-catalysed thermal decomposition of ethyl diazoacetate (2b) in the presence of (1b) yields mainly ethyl 6-phenyl-6H-dibenzothiopyran-6-ylacetate (4d), together with minor amounts of (probably) 6-ethoxycarbonyl-7-phenyl-6,7-dihydrodibenzothiepin (3d), but only the product of insertion of ethoxycarbonylcarbene into the C(6)-H bond, i.e. (4c), is observed from the reaction of (2b) with (1a).Formation of the products (3) and (4) is rationalized in terms of a thermal ylide exchange reaction of the unstable sulphonium ylides (7a-d), initially produced in competition with a Stevens-type rearrangement.In support of the above mechanism, pyrolysis of the stable 6H-dibenzothiopyran-5-io(bismethoxycarbonyl)methanide (7e) gave only the product of insertion of bismethoxycarbonylcarbene into the C(6)-H bond, i.e. the malonate (4e), whereas almost exclusive formation of the ring-expansion product (3f) occured on pyrolysis of the 6-phenyl derivative of the ylide (7e).
Reactivity of Triplet Diphenylcarbene towards the Sulphur Atom of 1,2,3-Benzothiazole
Benati, Luisa,Montevecchi, Pier Carlo,Spagnolo, Piero,Tundo, Antonio
, p. 1544 - 1548 (2007/10/02)
Thermal decomposition of diphenyldiazomethane (1) at 87 deg C in chlorobenzene in the presence of 1,2,3-benzothiadiazole (2) afforded 9-phenylthioxanthen (3), 6-phenyl-6H-dibenzothiopyran (4), 6-benzhydryl-6-phenyl-6H-dibenzothiopyran (5) and thianthren (6).Reaction products are explained in terms of attack on the sulphur atom of (2) by triplet diphenylcarbene, leading to decomposition of the heterocyclic nucleus with loss of nitrogen and formation of a diradical intermediate (7), from which products (3)-(6) can arise.Some evidence is presented that benzothiadiazole (2) may act as an an effective spin-trap for triplet diphenylcarbene, thus preventing reversible interconversion of singlet and triplet states.
