515-40-2Relevant articles and documents
Long sought synthesis of quaternary phosphonium salts from phosphine oxides: Inverse reactivity approach
Vetter, Anna C.,Nikitin, Kirill,Gilheany, Declan G.
supporting information, p. 5843 - 5846 (2018/06/13)
Quaternary phosphonium salts (QPS), a key class of organophosphorus compounds, have previously only been available by routes involving nucleophilic phosphorus. We report the realisation of the opposite approach to QPS utilising phosphine oxides as the electrophilic partner and Grignard reagents as nucleophiles. The process is enabled through the crucial intermediacy of the derived halophosphonium salts. The route does not suffer from the slow kinetics and limited availability of many parent phosphines and a broad range of QPS were prepared in excellent yields.
Ketone-catalyzed photochemical C(sp3)–H chlorination
Han, Lei,Xia, Ji-Bao,You, Lin,Chen, Chuo
, p. 3696 - 3701 (2017/06/13)
Photoexcited arylketones catalyze the direct chlorination of C(sp3)–H groups by N- chlorosuccinimide. Acetophenone is the most effective catalyst for functionalization of unactivated C–H groups while benzophenone provides better yields for benzylic C–H functionalization. Activation of both acetophenone and benzophenone can be achieved by irradiation with a household compact fluorescent lamp. This light-dependent reaction provides a better control of the reaction as compared to the traditional chlorination methods that proceed through a free radical chain propagation mechanism.
Visible Light-Induced Oxidative Chlorination of Alkyl sp3 C-H Bonds with NaCl/Oxone at Room Temperature
Zhao, Mengdi,Lu, Wenjun
supporting information, p. 4560 - 4563 (2017/09/11)
A visible light-induced monochlorination of cyclohexane with sodium chloride (5:1) has been successfully accomplished to afford chlorocyclohexane in excellent yield by using Oxone as the oxidant in H2O/CF3CH2OH at room temperature. Other secondary and primary alkyl sp3 C-H bonds of cycloalkanes and functional branch/linear alkanes can also be chlorinated, respectively, under similar conditions. The selection of a suitable organic solvent is crucial in these efficient radical chlorinations of alkanes in two-phase solutions. It is studied further by the achievement of high chemoselectivity in the chlorination of the benzyl sp3 C-H bond or the aryl sp2 C-H bond of toluene.
Oxidative C-C bond formation reactivity of organometallic Ni(II), Ni(III), and Ni(IV) complexes
Watson, Michael B.,Rath, Nigam P.,Mirica, Liviu M.
, p. 35 - 38 (2017/05/16)
The use of the tridentate ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3tacn) and the cyclic alkyl/aryl C-donor ligand-CH2CMe2-o-C6H4-(cycloneophyl) allows for the synthesis of isolable organometallic NiII, NiIII, and NiIV complexes. Surprisingly, the fivecoordinate NiIII complex is stable both in solution and the solid state, and exhibits limited C-C bond formation reactivity. Oxidation by one electron of this NiIII species generates a six-coordinate NiIV complex, with an acetonitrile molecule bound to Ni. Interestingly, illumination of the NiIV complex with blue LEDs results in rapid formation of the cyclic C-C product at room temperature. This reactivity has important implications for the recently developed dual Ni/photoredox catalytic systems proposed to involve high-valent organometallic Ni intermediates. Additional reactivity studies show the corresponding NiII species undergoes oxidative addition with alkyl halides, as well as rapid oxidation by O2, to generate detectable NiIII and/or NiIV intermediates and followed by C-C bond formation.
Regio-selective synthesis of key intermediates of fexofenadine
Kumar, Anil,Bhashkar, Bhuwan,Kumar, Harish,Singh, Gurpreet
, p. 2285 - 2287 (2015/12/19)
The present work is focused on improved process of preparation of fexofenadine which is achieved by regio-selective synthesis of intermediate; 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane. The said intermediate is prepared in good yields and with greater purity wherein the synthesis of side products like 1-oxoalkoxy-2-methyl-2-[3-(4-chloro-1-oxobutyl)phenyl]propane (metaisomer) is reduced to a great amount. The intermediate, 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane (para-isomer) where, alkyl group is selected from C2-5 carbon chain, is synthesized through preparation of 1-chloro-2-methyl-2-phenylpropane which upon reaction with potassium salt of aliphatic carboxylic acid followed by Friedel-Crafts acylation with 4-chlorobutyrylchloride results into desired intermediate, 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane and a side impurity, 1-oxoalkoxy-2-methyl-2-[3-(4-chloro-1-oxobutyl)phenyl]propane (meta-isomer) in the ratio of 1:0.09-0.15. The above said mixture can be directly used for the synthesis of fexofenadine and has an advantage of eliminating the purification process at intermediate stage and use of less volume of expensive solvents.
A process for producing 4-(4-halo-1-oxybutyl)-alpha,alpha-dimethylbenzene acetic acid or alkyl esters thereof
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Page/Page column 7, (2011/04/14)
Disclosed herein is a process for large scale production of pure 4-(4-halo-1-oxybutyl)-α,α-dimethylbenzene acetic acid or alkyl esters thereof, wherein the process comprises of condensing (2-halo-1,1-dimethyl-ethyl)benzene with acetate salt followed by acylation with ω-halo compound, hydrolyzing and cyclizing the resultant regioisomers, subsequently oxidizing and purifying to obtain pure regioisomer, further halogenating and/or esterifying the para regioisomer to produce 4-(4-halo-1-oxybutyl)-α,α-dimethylbenzene acetic acid or their alkyl esters.
Chlorination of various substrates in subcritical carbon tetrachloride
Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
experimental part, p. 2881 - 2888 (2010/06/16)
Various aliphatic hydrocarbons and the side chains of aromatic hydrocarbons were chlorinated in subcritical carbon tetrachloride. Chlorination of aromatic compounds including 1,4-disubstituted benzenes was investigated. Ketones and sulfones were stable under the employed conditions. Sulfoxides were converted into sulfides in a low to modest yields. The coupling adducts between olefins and carbon tetrachloride were obtained from the reactions of olefins.
Synthesis of ethophenprox
Rakhimov,Galin,Tomilov,Le
, p. 1629 - 1634 (2007/10/03)
An ethophenprox synthesis from easily available p-nitroneophyl chloride was developed. The reduction of the latter to aniline derivative followed by Sandmayer's and Claisen's reactions furnished p-ethoxyneophyl chloride that by condensation with 3-phenoxybenzyl alcohol in the presence KOH in DMSO yielded ethophenprox.
Mechanistic study of the reaction of 1,1-dihalo-2-methyl-2-phenylpropanes with LDA. Evidence for radical and carbene pathways
Ashby, E. C.,Mehdizadeh, Ali,Deshpande, Abhay K.
, p. 1322 - 1330 (2007/10/03)
An attempt was made to determine the mechanisms involved in the reactions of the model systems 1,1-dichloro-2-methyl-2-phenylpropane (1) and 1,1-diiodo-2-methyl-2-phenylpropane (2) with LDA.These systems were chosen as ones capable of providing evidence for the formation of radical as well as carbene products.The techniques employed in investigating the mechanistic features of these reactions involved studying the effect of the leaving group, the effect of radical and carbene trapping agents on the product distribution, and isotopic tracer experiments using labeled solvent (THF-d8) and nucleophile (LDA-d2).The major product of the reaction of the geminal dichloride (1) is thought to be derived from a chlorocarbene, whereas the geminal diiodide (2) appears to form products derived from both carbene and radical intermediates.On the basis of the results of radical trapping experiments and those of deuterium-labeling experiments, evidence is presented to support the notion that products A, E, and H are derived from a radical precursor.In addition, products A and H are also believed to be formed from the vinilyc halide D (or B) and the monoiodide E, respectively.Reasonable mechanisms for the formation of the other products formed in these reactions have been proposed on the basis of the available data.
Versatility of Zeolites as Catalysts for Ring or Side-Chain Aromatic Chlorinations by Sulfuryl Chloride
Delaude, Lionel,Laszlo, Pierre
, p. 5260 - 5269 (2007/10/02)
Zeolites catalyze chlorination of aromatics by sulfuryl chloride SO2Cl2.It is possible by an appropriate choice of the catalyst to effect at will, with very high selectivity, either the ring or the side-chain chlorination.Zeolite ZF520 is the choice catalyst for the former, because of its high Broensted acidity.Zeolite NaX (13X) is a fine catalyst for the latter, free-radical chlorination; the reaction is best effected in the presence of a light source; the catalyst can be reused many times with no loss in activity.Both reaction modes, the ionic (ring chlorination)and the radical (side-chain substitution), are likely to occur outside of the channel network in the microporous solid.The effects of various experimental factors - such as the nature of the solvent, the reaction time and temperature, the Broensted acidity of the solid support, the presence of radical inhibitors, and the quantity of catalysts - were investigated.The procedures resulting from this study are very easy to implement in practice and are quite effective.
