- Synthesis of 2-Cyano-1,1,2,2-tetraphenylethyl Cation and Silver Ion Assisted Solvolysis of sym-Tetraphenylethylene Dichloride
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The reaction of 3-chloro-2,2,3,3-tetraphenylpropanenitrile (2) with AgSbF6 or SbCl5 below -55 deg C in methylene chloride produces the stable, long-lived cation 2-cyano-1,1,2,2-tetraphenylethyl cation (5).Treatment of 5 with TMSCN affords a 98percent yield of 2,2,3,3-tetraphenylsuccinonitrile.It was also found that cation 5 generated with AlCl3 at 0 deg C can undergo intramolecular aromatic substitution to give 9-(cyanodiphenylmethyl)fluorene (8).In the reactions of sym-tetraphenylethylene dichloride (1) with CF3COOAg in the presence of methanol, it was found that tetraphenylethanone dimethyl ketal (9) can be synthesized in 91percent yield.Because rearrangement occured, 1-methoxy-1,2,2,2-tetraphenylethyl cation (15) is proposed as a reaction intermediate.In contrast, treatment of dichloride 1 with CF3CO2Ag in the presence of phenol or isopropyl or allyl alcohol did not produce the corresponding ketals but the 1,3-dioxolane ortho esters 19, 20, or 21 (2-alkoxy-2-trifluoromethyl)-4,4,5,5-tetraphenyl-1,3-dioxolanes).
- Wo, Shiming,Zieger, Herman E.,Millar, Michelle M.,Koch, Stephen A.
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- Conformations of 1,2-dicyano-1,1,2,2-tetraphenylethane and cyanodiphenylmethyl peroxide
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The solid-state structures of 1,2-dicyano-1,1,2,2-tetraphenylethane and cyanodiphenylmethyl peroxide are determined by X-ray crystallography. Both molecules adopt the trans conformation in the solid-state. Experimentally derived values of the energy diffe
- Lam, Yulin,Lee, Gene-Hsiang,Liang, Eping
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- Synthesis of Succinonitrile Derivatives by Homocoupling from Cyanohydrin Derivatives with a Low-Valent Titanium Reagent
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A method is described for synthesizing succinonitrile derivatives bearing alkyl or aryl substituents from cyanohydrin derivatives using low-valent titanium. The active species in this reaction is proposed to be a resonance hybrid of the TiIV nitrile enolate and TiIII alkyl radical.
- Endo, Ryusei,Kishida, Atsushi,Matsunaga, Kazuma,Nagasawa, Kokoro,Takatori, Kazuhiko
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- Electrocatalytic dimerization of diarylacetonitriles mediated by sodium halides
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A new electrocatalytic reaction affording tetraarylsuccinonitriles in 80-100% yields by the oxidation of diarylacetonitriles in an undivided cell with sodium halides as mediators is described.
- Elinson, Michail N.,Ilovaisky, Alexey I.,Merkulova, Valentina M.,Zaimovskaya, Tatiana A.,Belyakov, Pavel A.,Nikishin, Gennady I.
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p. 207 - 208
(2011/03/19)
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- THERMALLY MODULATED ANTIOXIDANTS
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Most carbon-centered free radical antioxidants are generated through hydrogen abstraction. Disclosed herein are a new class of antioxidant precursor compounds of the formula A-B, wherein upon exposure of the compounds to an increase in temperature, the co
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Page/Page column 49; 51
(2008/06/13)
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- Bond dissociation energies for radical dimers derived from highly stabilized carbon-centered radicals
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(Matrix Presented) The temperature dependence of the dissociation of dimers formed from highly stabilized carbon-centered radicals has been examined. Analysis of the data yields the bond dissociation energy (BDE) for the central head-to-head C-C bond in t
- Frenette, Mathieu,Aliaga, Carolina,Font-Sanchis, Enrique,Scaiano
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p. 2579 - 2582
(2007/10/03)
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- Selective and efficient heterogeneous hydration of nitriles to amides using silica supported manganese dioxide
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A highly efficient and selective method for hydration of nitriles to amides without formation of any detectable amount of acid, under heterogeneous reaction condition using silica supported manganese dioxide is reported. The mechanism of the reaction has been discussed. The reagent preparation is easy and carried out under microwave exposure within 5 min. The silica supported MnO2 reagent has been characterized by DRIFT and XRD techniques. Quantitative yields are obtained for commercially important heterocyclic amides such as pyridinecarboxamide, nicotinamide and pyrazinamide.
- Khadilkar, Bhushan M.,Madyar, Virendra R.
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p. 2814 - 2819
(2007/10/03)
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- Oxidative nucleophilic substitution of hydrogen in nitroarenes with phenylacetonitrile derivatives
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Tertiary carbanions generated from α-substituted phenylacetonitriles in liquid ammonia add to nitrobenzenes in the para position to form the corresponding σ(H)-adducts which are transformed, depending on the starting nitriles and the reaction conditions, to products of oxidative nucleophilic substitution of hydrogen, ONSH or vicarious nucleophilic substitution, VNS.
- Makosza, Mieczyslaw,Stalinski, Krzysztof
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p. 8797 - 8810
(2007/10/03)
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- Alkylation of Nitrile Anions by Tertiary α-Halo Ketones and Nitriles
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Potassium salts of nitriles bearing carbethoxy, cyano, or phenyl groups at the α carbon react with tertiary α-halo ketones and nitriles (1-5) in DMSO or HMPA to provide the alkylated β-keto- or β-cyano-β,β-dialkyl nitriles 6-10 in useful yields. (PhCHCN)(-) undergoes cyclization with p-XC6H4COCCl(CH3)2 to produce 2(5H)-furanone 11.Reaction of (Ph2CCN)(-) with PhCOCCl(CH3)2 affords the hydrolyzed ketone 12a and recovered carbon acid, while the anion undergoes oxidative dimerization to NCCPh2CPh2CN with p-O2NC6H4COCCl(CH3)2 with concomitant formation of the reduced ketone p-O2NC6H4COCH(CH3)2 and the hydrolyzed ketone 12b.The alkylations of (-) and (-) with p-O2NC6H4COCX(CH3)2 take place by the SRN1 process.
- Ros, Francisco,Rosa, Jose de la,Enfedaque, Juan
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p. 5419 - 5424
(2007/10/02)
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- Titanium(IV) Chloride Catalyzed Cyanation of Benzylic Halides With Trimethylsilyl Cyanide
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Six sterically hindered benzylic chlorides have been substituted with cyano groups in excellent yields with trimethylsilyl cyanide and titanium tetrachloride in methylene chloride.Both monochloro substrates such as diphenylmethyl chloride and triphenylmethyl chloride and dichloro substrates such as dichlorodiphenylmethane and sym-tetraphenylethylene dichloride were studied.Because isonitriles are plausible reaction intermediates, the isomerization of trityl isonitrile by TiCl4 and by trityl tetrafluoroborate was studied at 0 and -78 deg C.Both reagents catalyze conversion to triphenylacetonitrile at 0 deg C while only trityl tetrafluoroborate is effective at -78 deg C.It was also found that trityl tetrafluoroborate reacts with trimethylsilyl cyanide in the absence of TiCl4 to give triphenylacetonitrile in 96percent yield.
- Zieger, Herman E.,Wo, Shiming
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p. 3838 - 3840
(2007/10/02)
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- Radical and Ionic Reactions of (Benzoylmethyl)mercurials
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Photolysis of PhCOCH2HgCl or (PhCOCH2)2Hg yields benzoylmethyl radicals which can be trapped by anions such as Me2C=NO2-, RC(CO2Et)2-, RC(O-)=CH2 or by other electron-rich systems such as (RO)3P, N-methylpyrrole, enamines, or norbornene.Electron transfer from the adduct radicals to the mercurials yields PhCOCH2A from the anions A-, PhCOCH2P(O)(OR)2 from P(OR)3, and the phenacyl derivative from N-methylpyrrole or enamines.Easily oxidized anions such as PhCOCPh2- or PhC(CH3)=NO2- react with PhCOCH2* by electron transfer to yield the dimer derived from the anion.Addition of PhCOCH2* to norbornene yields a substituted 3-benzoylpropyl radical which cyclizes at the ortho position of the benzoyl group to give the α-tetralone derivative.
- Russell, Glen A.,Kulkarni, Shekhar V.,Khanna, Rajive K.
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p. 1080 - 1086
(2007/10/02)
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- Arene Hydrides, 8. - SET vs. Nucleophilic Attack in Reactions of α-Bromoisobutyrophenone with Carbanions. Fragmentation of the Anion of Tetrahydrobianthracene
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SET is the main reaction pathway between α-bromoisobutyrophenone (1) and the carbanions 7a-j- of diarylmethanes or disubstituted acetonitriles: 7- 7. + e and e + 1 Br- PhCOCMe2. (3).Main secon
- Werry, Juergen,Stamm, Helmut,Sommer, Andreas
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p. 1553 - 1562
(2007/10/02)
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- Reactions with Stable Phenoxyl Radicals
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Hydrogen abstraction from activated methyl, methylene, and methine compounds with 4-methoxy-2,6-diphenylphenoxyl proved to be a useful approach for the synthesis of the corresponding ethers of 4-methoxy-2,6-diphenylphenol.With triple activated methine com
- Jonge, Cornelis R.H.I. de
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p. 299 - 304
(2007/10/02)
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- THE REACTION OF CARBANIONS WITH TERT-BUTYL RADICALS
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The SRNl free radical chain reaction of Me3CHgCl with nitronate -O2N=C(R1)(R2)> and phenone enolate -)=C(R1)(R2)> anions yields the C-alkylation products 1)(R2)NO2, PhCOC(R1)(R2)CMe3>.Competitive reactions between pairs of anions demonstrate that as the basicity of the anion increases the reactivity toward Me3Cat first increases and then decreases.An inverted reactivity order is also observed with phenylacetonitrile anions.In early transition state reactions, the nucleophilic character of the tert-butyl radical apparently controls the reactivity by virtue of a transition state involving transfer of the electron from radical to the LUMO of the resonance stabilized anion.
- Russell, Glen A.,Khanna, Rajive K.
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p. 4133 - 4146
(2007/10/02)
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- Reactions of Trimethylsilyl Cyanide and N-(Trimethylsilyl)diphenylmethyleneamine with Nitrones and Thermal Decompositions of Their Adducts
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Trimethylsilyl cyanide (1) and N-(trimethylsilyl)diphenylmethyleneamine (2) reacted with α-aryl-N-phenylnitrones to afford the corresponding 1:1 adducts 4 and 5 respectively.Thermal decomposition of 4 in refluxing xylene gave azoxybenzene, stereoisomers of 2,3-diarylsuccinonitriles, α-aminonitriles and/or benzanilides, whose yields depended on the nature of substituents on phenyl group of 4.On heating in benzene 5 afforded a mixture of azoxybenzene and meso-N,N'-bis(diphenylmethylene)-1,2-diarylethylenediamines.On the other hand, reactions of 1 and 2 with N-(diphenylmethylene)aniline N-oxide or N-(9-fluorenylidene)aniline N-oxide did not give the corresponding 1:1 adducts, but instead compounds arising from thermal decomposition of initial 1:1 adducts were directly obtained.The reaction of 1 with N-(p-diethylaminophenyl)-α-phenylnitrone leading to the corresponding α-imino nitrile is also described.
- Tsuge, Otohiko,Urano, Satoshi,Iwasaki, Takahiko
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p. 485 - 489
(2007/10/02)
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