- C-CN BOND CLEAVAGE UNDER MILD CONDITIONS PROMOTED BY ELECTRON-RICH COBALT COMPLEXES
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Electron-rich cobaltate dinitrogen complex, Li(Et2O)3 1, reacts with alkyl and aryl nitrile compounds causing the cleavage of C-CN bond under mild conditions to release hydrocarbons.Catalytic activity of the cobalt complex to isomerize allyl cyanide to crotononitrile is also noted.
- Ozawa, Fumiyuki,Iri, Kiyoshi,Yamamoto, Akio
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Read Online
- Base-Catalyzed Isomerization of 3-Butenenitrile. Relative Nucleophilicities of Carbanions, Nitranions, Oxanions, and Thianions toward Hydrogen
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Rate constants for base-catalyzed isomerization of CH2=CHCH2CN to CH3CH=CHCN in Me2SO solution by families of carbanions (C(1-)), nitranions (N(1-)), oxanions (O(1-)), and thianions (S(1-)) have been measured.The relative catalytic effect of these anions at the same basicity is S(1-), O(1-) > N(1-) > C(1-).This order is the same as that observed previously for attack of families of anions of these types on a β-hydrogen atom in elimination reactions from cyclohexyl bromide, but it differs from that for attack on carbon in SN2 reactions: S(1-) >> C(1-) > O(1-) > N(1-).The Broensted coefficients, wich measure the sensitivity of the rates to changes in basicity, were in the range 0.8-1.These large values are consistent with previous values determined for deprotonation of α-CN carbon acids, but not with the predictions of the Leffler-Grunwald rate-equilibrium equation.A review of the literature failed to provide support for the Leffler-Grunwald postulate that β will approach zero for exergonic proton transfers from carbon acids and unity for endergonic proton transfers.The results are rationalized by a two-step mechanism for proton transfers involving a hydrogen-bonded carbanion intermediate.The failure of substituent effects on protonations of carbanions to conform to those observed in the deprotonation of the corresponding carbon acids provides evidence against a one-step mechanism.Our observations argue against the application of the Hammond-Leffler postulate to most organic reactions over the usual reactivity ranges studied.
- Bordwell, Frederick G.,Hughes, David L.
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- Base controlled diverse reactivity of allyl cyanide for synthesis of multi-substituted benzenes
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A base controlled regioselective 1,6-cyanoallylation of suitably functionalized 2H-pyran-2-ones has been demonstrated for the synthesis of various multi-substituted benzenes through a tandem process. We observed that lithium hydroxide provides a major product from α-attack and a minor product from γ-attack of allyl cyanide, while the use of sodium hydride as a base exclusively provides the product by γ-attack of allyl cyanide. We have also performed NMR experiments to understand the mechanistic pathway. The structure of the compound was confirmed by single crystal X-ray analysis.
- Yadav, Pratik,Shaw, Ranjay,Elagamy, Amr,Kumar, Abhinav,Pratap, Ramendra
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- Spectra of carbanions formed from ally1 cyanide during isomerization in zeolite Nay-FAU with strong basic sites
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Double bond isomerization of ally1 cyanide to crotononitrile over a basic zeolite catalyst was monitored by IR and UV-VIS spectroscopy in order to get information on the surface intermediates involved. Due to the spectral changes the occurence of a carbanionic intermediate seems to be highly probable characterized by an absorption at 400 nm.
- Hannus, Istvan,Foerster, Horst,Tasi, Gyula,Kiricsi, Imre,Molnar, Arpad
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- Relative Donor-Atom Effects on Rates of Isomerization of 3-Butenenitrile Catalyzed by Anions of the Same Basicity
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For base-catalyzed isomerization of 3-butenenitrile in Me2SO solution the order of rate constants for anions of the same basicity is ArS->ArO->RSO2NAr->9-G-Fl- (9-substituted fluorenyl carbanions).The relative rate constants vary somewhat with basicity since the Broensted β values are 0.77, 1.0, 0.82, and ca. 0.8, respectively.
- Bordwell, Frederick G.,Hughes, David L.
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Read Online
- LJ reaction in the preparation wittich reagent and application of glufosinate in
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The present invention relates to an application of a new LJ intramolecular isomerization reaction in preparation of a wittig reagent and a herbicide of glufosinate-ammonium. With the application, a new approach of a synthesis route for preparing the wittig reagent and the glufosinate-ammonium is developed, the disadvantages of the existing wittig reaction are improved, and the industrial design of the glufosinate-ammonium production is improved.
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Paragraph 0094; 0095
(2017/12/04)
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- Unusual reactivity of N-tert-butylimines under FVT conditions
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Thermal reactions of N-tert-butyl-(E)-crotonaldimine (1a) and 1,4-di-(tert-butyl)-1,4-diazabuta-1,3-dien (glyoxal-bis-N-tert-butylimine) (1b) under FVT conditions have been studied. It has been found that at 800 °C compound 1a yielded pyrrole and crotonon
- Le?niak, Stanis?aw,Pasternak, Beata,Justyna, Katarzyna,Vu, Thien Y.,Huynh, Thi Kieu Xuan,Khayar, Sa?d,Dargelos, Alain,Chrostowska, Anna
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p. 722 - 729
(2013/07/27)
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- New tetraphosphorus ligands for highly linear selective hydroformylation of allyl and vinyl derivatives
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New tetraphosphorus ligands have been developed and applied in the rhodium-catalyzed regioselective hydroformylation of a variety of functionalized allyl and vinyl derivatives. Remarkably high linear selectivity was obtained by these tetraphosphorus ligands. The ligand that bears strong electron-withdrawing 2,4-difluorophenyl groups is the most effective one in affording linear aldehydes. The Rh/tetraphosphorus ligand catalyst is highly effective to produce linear aldehydes from functionalized allyl derivatives with heteroatoms or aromatic groups directly adjacent to the allyl group. For vinyl derivatives, the ligand is highly linear selective for acrylic derivatives, styrene, vinyl pyridine, and vinyl phthalimide. Linear to branch ratios of 26:1 and 10:1 were obtained for the hydroformylation of styrene and allyl cyanide, respectively. New tetraphosphorus ligands have been developed and applied in the rhodium-catalyzed regioselective hydroformylation of a variety of allyl and vinyl olefins (see scheme). Remarkably high linear selectivities were obtained by these ligands. Linear-to-branch ratios of 26:1 and 10:1 were obtained for the hydroformylation of styrene and allyl cyanide, respectively. Copyright
- Cai, Chaoxian,Yu, Shichao,Cao, Bonan,Zhang, Xumu
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experimental part
p. 9992 - 9998
(2012/09/07)
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- CONTROLLED DRUG RELEASE FROM SOLID SUPPORTS
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The invention relates to solid supports useful in medical applications that provide controlled release of drugs, such as peptides, nucleic acids and small molecules. The drugs are covalently coupled to the solid support through a linkage that releases the drug or a prodrug through controlled beta elimination.
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Page/Page column 31-32
(2011/11/30)
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- CONTROLLED RELEASE FROM MACROMOLECULAR CONJUGATES
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The invention relates to conjugates of macromolecular carriers and drugs comprising linkers that release the drug or a prodrug through rate-controlled beta-elimination, and methods of making and using the conjugates.
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Page/Page column 24-25
(2011/11/30)
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- Copper-mediated synthesis of substituted 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles via C-H functionalization/C-N/C-O bond formation
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An efficient method for the transformation of N-benzyl bisarylhydrazones and bisaryloxime ethers to functionalized 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles is described. The protocol involves a copper(II)-mediated cascade C-H functionalization/C-N/C-O bond formation under neutral conditions. Substrates having either electron-donating or -withdrawing substituents undergo the cyclization to afford the target heterocycles at moderate temperature.
- Guru, Murali Mohan,Ali, Md Ashif,Punniyamurthy, Tharmalingam
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scheme or table
p. 5295 - 5308
(2011/08/05)
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- Direct catalytic asymmetric addition of allyl cyanide to ketones via soft lewis acid/hard bronsted base/hard lewis base catalysis
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We report that a hard Lewis base substantially affects the reaction efficiency of direct catalytic asymmetric γ-addition of allyl cyanide (1a) to ketones promoted by a soft Lewis acid/hard Bronsted base catalyst. Mechanistic studies have revealed that Cu/(R,R)-Ph-BPE and Li(OC 6H4-p-OMe) serve as a soft Lewis acid and a hard Bronsted base, respectively, allowing for deprotonative activation of 1a as the rate-determining step. A ternary catalytic system comprising a soft Lewis acid/hard Bronsted base and an additional hard Lewis base, in which the basicity of the hard Bronsted base Li(OC6H4-p-OMe) was enhanced by phosphine oxide (the hard Lewis base) through a hard-hard interaction, outperformed the previously developed binary soft Lewis acid/hard Bronsted base catalytic system, leading to higher yields and enantioselectivities while using one-tenth the catalyst loading and one-fifth the amount of 1a. This second-generation catalyst allows efficient access to highly enantioenriched tertiary alcohols under nearly ideal atom-economical conditions (0.5-1 mol % catalyst loading and a substrate molar ratio of 1:2).
- Yazaki, Ryo,Kumagai, Naoya,Shibasaki, Masakatsu
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supporting information; experimental part
p. 5522 - 5531
(2010/07/04)
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- Looking for heteroaromatic rings and related isomers as interstellar candidates
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Finding complex organic molecules in the interstellar medium (ISM) is a major concern for understanding the possible role of interstellar organic chemistry in the synthesis of prebiotic species. The present interdisciplinary report is a prospective study aimed at helping detection of heteroaromatic compounds or at least of some of their isomers in the ISM. The thermodynamic stabilities of the C4H5N, C4H4O, C4H4S families were calculated using density functional theory (DFT). It was found that pyrrole, furan and thiophene are unambiguously the most stable isomers at the 10-50 K temperatures of the ISM. Several of the less stable isomers were synthesized and flash vacuum thermolysis experiments were performed on these species. Although the detection of pyrrole in the pyrolysis of many compounds has been reported in the literature, we observed that none of its isomers led to pyrrole in these conditions, which suggests that other formation routes are to be considered. On the other hand, these three aromatic compounds present a very high stability, few % been decomposed at 1500 K by flash vacuum thermolysis; these experiments also show a great stability of crotonitrile that is the most stable compound that can be formed in these conditions. The rotational constants, dipole moments and IR frequencies of the low-lying isomers are given to encourage laboratory experiments on these prototype molecules.
- Lattelais,Ellinger,Matrane,Guillemin
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experimental part
p. 4165 - 4171
(2011/08/02)
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- Efficient conversion of aldoximes to nitriles using phosphoric acid diethyl ester 2-phenylbenzimidazol-1-yl ester
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Aromatic aldoximes were converted to the corresponding nitriles in good to excellent yields by employing phosphoric acid diethyl ester 2- phenylbenzimidazol-1-yl ester as reagent. The method was equally effective for oximes bearing electron-donating and electron-withdrawing substituents. Graphical Abstract: [Figure not available: see fulltext.]
- Kokare, Nagnnath D.,Shinde, Devanand B.
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experimental part
p. 185 - 188
(2010/03/26)
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- Synthesis of aryliminoacetonitriles under FVT conditions or by dehydrogenation of arylaminoacetonitriles: an NMR and UV-photoelectron spectroscopy study
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The synthesis of [(E)-arylimino]-acetonitriles 3 has been described. It was found that the title compounds can be obtained on the three ways, namely by: (i) dehydrogenation of arylaminoacetonitriles 1, (ii) thermal fragmentation of 1-aryl-4-cyano-β-lactams 4 and (iii) retro-ene reaction of (allyl-p-methoxyphenyl-amino)-acetonitrile (7a) under FVT conditions. 1H and 13C NMR spectra of compounds 3, 5 and 6, and all their precursors 1 and 4, were recorded and analysed in detail using chemical shifts δH and δC [from GIAO DFT B3LYP/6-31(d) calculations] and J-couplings predicted at the DFT B3LYP/IGLO-II level. Also, UV-photoelectron spectra of 4a,d and 3a,d were measured and analysed considering the theoretical evaluation of their ionisation potentials.
- Le?niak, Stanis?aw,Chrostowska, Anna,Kuc, Dawid,Maciejczyk, Ma?gorzata,Khayar, Sa?d,Nazarski, Ryszard B.,Urbaniak, ?ukasz
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experimental part
p. 10581 - 10589
(2010/02/28)
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- DMF-catalysed thermal dehydration of aldoximes: A convenient access to functionalized aliphatic and aromatic nitriles
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N,N-Dimethylformamide was found to act as solvent and catalyst in the dehydration of aldoximes to nitriles. The reaction required heating at 135°C and yields of nitriles were moderate to good. (Benzylideneaminooxy)formaldehyde was detected as an intermediate in one of the reactions. Georg Thieme Verlag Stuttgart.
- Supsana, Paraskevi,Liaskopoulos, Theodoras,Tsoungas, Petros G.,Varvounis, George
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p. 2671 - 2674
(2008/02/11)
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- An efficient and convenient KF/Al2O3 mediated synthesis of nitriles from aldehydes
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KF/Al2O3 brings about a facile one-pot and economical conversion of various aryl and alkyl aldehydes into the corresponding nitriles in high yields by reaction with hydroxylamine hydrochloride.
- Movassagh, Barahman,Shokri, Salman
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p. 6923 - 6925
(2007/10/03)
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- The thermal decomposition of 5-membered rings: A laser pyrolysis study
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The mechanisms of pyrolysis of cyclopentadiene, furan, pyrrole and thiophene have been investigated using a combination of IR laser powered homogeneous pyrolysis, chemical and physical trapping of radical intermediates, and use of precursors specifically designed to generate selected radical intermediates. The results confirm the central role played by free radicals in the cases of cyclopentadiene and thiophene, and the dominant step of 1,2-H shifts in the cases of furan and pyrrole. The experimental results may be interpreted according to the high level ab initio calculations recently reported in the literature.
- Hore, Nathan R.,Russell, Douglas K.
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p. 606 - 613
(2007/10/03)
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- Synthesis and spectroscopic characterization of 1-13C- and 4-13C-plastoquinone-9
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This paper presents the synthesis of 1-13C- and 4-13C-plastoquinone-9 and their characterization with NMR spectroscopy and mass spectrometry. The synthetic scheme has been further adapted to introduce 13C-labeled plastoquinones on all individual and on each combination of positions in the quinone ring. Also a two-step scheme is disclosed to prepare unlabeled plastoquinone-9. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Boers, Rutger B.,Randulfe, Yolanda Pazos,Van Der Haas, Hendrikus N. S.,Van Rossum-Baan, Marleen,Lugtenburg, Johan
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p. 2094 - 2108
(2007/10/03)
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- Direct transformation of aldehydes to nitriles using iodine in ammonia water
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Treatment of aromatic, heterocyclic, aliphatic, conjugated, and polyhydroxy aldehydes with iodine in ammonia water at room temperature for a short period gave the corresponding nitriles in high yields.
- Talukdar, Sanjay,Hsu, Jue-Liang,Chou, Tzu-Chi,Fang, Jim-Min
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p. 1103 - 1105
(2007/10/03)
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- Thermal decomposition of 4-methylpyrimidine. Experimental results and kinetic modeling
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The decomposition of 4-methylpyrimidine was studied behind reflected shock waves in a pressurized driver single-pulse shock tube at 1160-1330 K and overall densities of ～ 3 × 10-5 mole/cc. A plethora of decomposition products, both with and without nitrogen, (HCN, CH3CN, C2H3CN, CH4, C2H6, C2H4, etc.) was found in the post-shock mixtures. The attack of methyl radicals on the methyl group in 4-methylpyrimidine produced CH4, which was a major product among the species not containing nitrogen, leaving the radical 4-methylene pyrimidyl. The H atoms and methyl radicals initiated a chain mechanism by abstraction of an H atom from the methyl group and by dissociative attachment of an H atom and removal of a methyl group from the ring. The decomposition mechanism was discussed.
- Lifshitz, Assa,Suslensky, Aya,Tamburu, Carmen
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p. 3542 - 3554
(2007/10/03)
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- Deamination Reactions, 54. - Decomposition of 1-Cyano-1-propanediazonium Ions
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The nitrous acid decomposition of 2-aminobutanenitrile (9) was studied with regard to product distribution and stereochemistry.The formation of 2-(hydroxyimino)butanenitriles (21, 22; 8-28percent) indicates the intervention of 1-cyanopropyl radicals (24) that are captured by NO.The polar reactions lead mainly to elimination (10-13) and nucleophilic substitution (14-16), rearrangement playing a minor role. (R)-9 was prepared from (R)-2-aminobutanoic acid.The nitrous acid deamination of (R)-9 afforded the cyanohydrin 16 with 81percent net inversion.Owing to destabilization of the carbocation 26 by CN, the SN2 route of nucleophilic displacement is preferred over SN1.The influence of CN is shown to be smaller than that of CF3. Key Words: α-Cyanodiazonium ions / α-Cyanoalkyl radicals / Carbocations, destabilized / Substitution, nucleophilic / Deamination reactions / Diazonium ions / Radicals
- Bunse, Michael,Kirmse, Wolfgang
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p. 1499 - 1502
(2007/10/02)
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- Kinetics of Pyrolysis of the Isomeric Butenenitriles and Kinetic Modeling
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Kinetics of pyrolysis of the butenenitrile isomers, cis- and trans-crotonitrile and allyl cyanide, have been studied dilute in argon in a single-pulse shock tube over the temperature range of 1200-1500 K at uniform gas residence times behind the reflected shock of between 650 and 750 μs and at pressures between 18 and 20 atm.Thermal decomposition was preceded by isomerization of the butenenitriles whose rates are coupled with the rates of thermal decomposition.The decomposition was found to follow a free-radical mechanism, with the major chain involving propagation reactions of the cyanomethyl radical to produce acetonitrile and acetylene.Other routes important to the mechanism involve hydrogen atom addition to the butenenitriles.HCN principally arises from this route.A detailed kinetic reaction model is presented to model the experimental reactants and products profiles as a function of temperature.From the modeling and experiment, the following initiation rate constants have been obtained: trans-CH3CH=CHCN -> CH3 + HC=CHCN (k-11 = 1017.45 exp(-96.5/RT) s-1), cis-CH3CH=CHCN -> CH3 + HC=CHCN (k-12 = 1017.53 exp(-98.5/RT) s-1), CH2=CHCH2CN -> H2C=CH + CH2CN (k-13 = 1015.53 exp(-82.6/RT) s-1), where the activation energies are in kcal mol-1.
- Doughty, Alan,Mackie, John C.
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p. 272 - 281
(2007/10/02)
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- Method for preparing α,β-unsaturated nitriles
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A method for preparing an α,β-unsaturated nitrile comprises bringing an α-oxycarboxylic acid amide represented by the following general formula: STR1 wherein R' and R each represents a hydrogen atom or an alkyl group, with the proviso that at least one of R' and R represents an alkyl group, into contact with a solid acid catalyst with heating in the presence of water in a molar ratio of not more than 15 with respect to the α-oxycarboxylic acid amide. The method makes it possible to directly produce an α,β-unsaturated nitrile at high yield and high selectivity utilizing an α-oxycarboxylic acid amide as a starting material, which can easily be obtained from an α-oxynitrile.
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- Wittig Reactions of Ylide Anions derived from Stabilised Ylides
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Ester- and nitrile-stabilised ylide anions are more reactive than the corresponding ylides and react with aldehydes and ketones to give alkenes in good yields; the reactivity of stabilised triphenylphosphonium ylides is greatly increased by the replacement of one phenyl substituent.
- McKenna, Eugene G.,Walker, Brian J.
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p. 568 - 569
(2007/10/02)
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- Assessment of the Cyano Substituent Effect in the Inhibited Pyrolysis Kinetics of ω-Bromonitriles in the Gas Phase
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The kinetics of the gas-phase pyrolysis of several bromonitriles were determined in a static system over the temperature range of 389.7-470.1 deg C and the pressure range of 38.5-139 Torr.The reactions in seasoned vessels, and in the presence of at least a 4-fold excess of the free-radical inhibitor propene and/or toluene, are homogeneous and unimolecular and follow a first-order rate law.The rate coefficients are given by the following Arrhenius equations: for 3-bromopropionitrile, log k1(s-1) = (13.56+/-0.44)-(231.9+/-6.0)kJmol-1 (2.303RT)-1; for 4-bromobutyronitrile, log k1(s-1) = (14.12*/-0.33) -(233.5+/-4.5)kJmol-1 (2.303RT)-1; for 5-bromovaleronitrile, log k1(s-1) = (13.79+/-0.19)-(225.7+/-2.6)kJmol-1(2.303RT)-1.The electron-withdrawing effect of the CN group along the carbon chain deactivates the HBr elimination during pyrolysis.A plot of the log krel of the cyano substituents in ω-bromonitriles against ?* values gives a good straight line with ρ* = -0.24, correlation coefficient r = 0.988, and intercept = -0.054 at 400 deg C.This slope inflects at ?*(CH3) = 0.00 with another good straight line derived by plotting the log krel vs ?* values of alkyl β-substituted ethyl bromides (? = -1.87, r = 0.991, and intercept = 0.056 at 400 deg C).The present result is explained in terms of slight alteration in the polarity of the transition state due to changes of electronic transmission at the carbon reaction center.
- Chuchani, Gabriel,Dominguez, Rosa M.
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p. 203 - 205
(2007/10/02)
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- Solid Base-catalysed Rearrangement of Methacrylonitrile to Crotononitrile
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MgO and CaO catalysts have shown high activity for the formation of crotonitrile (cis/trans=6/4) in the rearrangement of methacrylonitrile.
- Kurokawa, Hideki,Nakamura, Satoru,Ueda, Wataru,Morikawa, Yutaka,Moro-oka, Yoshihiko,Ikawa, Tuneo
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p. 658 - 659
(2007/10/02)
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- Flash-vacuum Pyrolysis of N-Vinylbenzotriazoles: Formation of N-Phenylketenimines
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A real time analysis of the flash-vacuum pyrolysis products of 1-vinyl-, 1-(2-methylprop-1-enyl)-, and 1-styryl-benzotriazole (3), (16), and (18) has been performed by tandem mass spectrometry.In the 500-700 deg C temperature range, these compounds lose nitrogen yielding the N-phenylketenimines (14), (17), and (19), respectively.At higher pyrolysis temperatures (3) gives indole (4) via isomerization of (14), whereas from (16) the secondary products of (17) are benzene and methacrylonitrile.In a preparative pyrolysis of (18) at 800 deg C 2- and 3-phenylindole (9) and (10) respectively, have also been detected.
- Maquestiau, Andre,Beugnies, Didier,Flammang, Robert,Katritzky, Alan R.,Soleiman, Mohammed,at al.
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p. 1071 - 1076
(2007/10/02)
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- Chemie der α-Aminonitrile. 1. Mitteilung. Einleitung und Wege zu Uroporphyrinogen-octanitrilen
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Chemistry of α-Aminonitriles I: Introduction and Pathways to Uroporphyrinogen-octanitriles.An introduction to experimental studies on the chemistry of α-aminonitriles potentially relevant to the problems of prebiotic chemistry is presented.The framework of conditions wherein the investigations is chosen to be carried out implies both molecular oxygen and - whenever feasible - water to be excluded from reaction conditions.This study focusses on 2-amino-2-propenenitrile (3) (Scheme 6) as central starting material of reaction sequences which aim at the nitrile forms of proteinogenic amino acids as well as at the aza forms of building blocks of biological cofactor molecules as their targets (Scheme 5).Schemes 13, 16, 23 as well as 25, and 26 summarize reaction sequences by which 3 is tranformed within the definied framework of conditions into the thermodynamic (statistically controlled) mixture of the four isomeric uroporphyrinogen-octanitriles 57-60.HPLC's of such mixtures document the dominance of the least symmetrical isomer whose constitutional pattern of peripheral substituents happens to be the one present in all biological porphinoids.Preparative procedures for the synthesis of 3 (Scheme 9), the β,β-disubstututed pyrrol-nitriles 30, 53, and 54 (Scheme 19) as well as the porphyrinogen-octakis(propionitrile) and -octakis(acetonitrile) 65 and 66, respectively (Scheme 24) are given.
- Ksander, Gary,Bold, Guido,Lattmann, Rene,Lehmann, Christian,Frueh, Thomas,et al.
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p. 1115 - 1172
(2007/10/02)
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- Substituent and Ring Size Dependence of the 4J(Me-C-C-H) Coupling Constant
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The magnitude of the 4J proton-proton coupling constant across the fragment CH3-C-C-H (a probe of the bond order between the central sp2-sp2 hybridized carbon atoms) has been found to be essentially independent of substitution on a toluene fragment and the size of the ring containing the ortho-allylic fragment.The coupling constant is sensitive to direct substitution on the ortho-allilyc fragment, especially where the substituent is placed α to methyl group.KEY WORDS - 4J proton-proton coupling constant ortho-benzylic coupling constant ring size dependence substituent dependence
- Collins, M. J.,Hatton, P. M.,Sternbell, S.,Tansey, C. W.
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p. 824 - 828
(2007/10/02)
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- BENZOCYCLOBUTENE AMINOALKYLENE ETHERS AND THIOETHERS, PHARMACEUTICAL COMPOSITIONS AND USE
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A class of benzocyclobutene aminoalkylene ether and thioether compounds exhibiting pharmacological activity, including anti-secretory and anti-ulcerogenic activity, pharmaceutical compositions comprising these compounds, and methods for the treatment of gastrointestinal hyperacidity and ulcerogenic disorders in mammals using said compositions.
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- ELECTROOXIDATIVE DESULFENYLATION OF MICHAEL-TYPE THIOL ADDUCTS OF α,β-UNSATURATED ESTERS, KETONES, AND NITRILES
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Michael adducts of ethanethiol with α,β-unsaturated esters ketones,and nitriles are conveniently desulfenylated under neutral conditions by an electrooxidation involving bromonium ion mediation.
- Kimura, Makoto,Matsubara, Shinichi,Sawaki, Yasuhiko,Iwamura, Hiizu
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p. 4177 - 4178
(2007/10/02)
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- Reaction of Electrochemically Generated Triphenylphosphine Radical Cation with Amides and Ureas
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Constant-current electrolysis of triphenylphosphine in dichloromethane in the presence of primary amides and N,N'-disubstituted ureas resulted in the formation of nitriles and carbodiimides, respectively.Dehydrosulfurization of thiobenzamide and N,N'-dicyclohexylthiourea was also effected by electrlysis under the same conditions, but probably through mechanisms different from those of dehydration of the corresponding amide and urea.Keywords-constant-current electrolysis; triphenylphosphine; primary amide; N,N'-disubstituted urea; nitrile; carbodiimide
- Ohmori, Hidenobu,Sakai, Kiyoshi,Nagai, Noriko,Mizuki, Yasuyuki,Masui, Masaichiro
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p. 373 - 376
(2007/10/02)
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- Photoreactivite des complexes nitriles-cuivre(I) et (II). II. Systeme cyanure d'allyle-cuivre(I) et (II)
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Through complexation with copper I, the allyl cyanide ligands has been shown to be converted in the dark into cis+trans crotonitrile.The photoreactivity of allyl cyanide-copper II complexes provides evidence that the ligand behaves like an α,β unsaturated nitrile.In both cases, the copper atom is bonded with the nitrogen atom of the allyl cyanide by charge transfer from the ligand to the metal (LMCT).
- Bolte, Michele,Lemaire, Jacques
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p. 1492 - 1496
(2007/10/02)
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- Heterogeneous Metathesis of Unsaturated Nitriles
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Unsaturated nitriles of the general formula CH2=CHnCN, where n>1, undergo metathesis at room temperature in the presence of the catalyst Re2O7-Al2O3, activated with a small amount of Me4Sn or Et4Sn.
- Aardweg, Godefridus C. N. van den,Bosma, Ruud H. A.,Mol, Johannes C.
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p. 262 - 263
(2007/10/02)
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- PREPARATION OF UNSATURATED NITRILES
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The yield and the rate of formation of nitriles X-CH=CH-CN and 3- or 4-substituted nitriles X-C6H4CN (X=CH3; OR; SR; COOCH3) were investigated in the reaction of vinyl and aryl bromides with CN1-, under catalysis with Pd0 and macrocyclic polyethers, and in the reaction with CuCN in dipolar aprotic solvents.Individual procedures were compared from the point of view of the possibility of a preparative utilization.
- Prochazka, Milos,Siroky, Miroslav
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p. 1765 - 1773
(2007/10/02)
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- Mechanism of Gas Phase Cyanation of Alkenes and Aromatics
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ICN was photolyzed at 254 nm in the gas phase in the presence of 15-20 torr of certain alkenes or aromatics.The products were analyzed by GC-MS.Ethene gave acrylonitrile; propene gave acrylonitrile, allyl cyanide and cis- and trans-1-cyanopropene; 2-methylpropene gave 2 cyanopropene; benzene gave benzonitrile; toluene gave benzonitrile and 2-, 3-, and 4-cyanotoluene.These products are explained by a mechanism involving attack of CN on the organic to give vibrationally excited radicals.These radicals rapidly fragment, producing the major products, or react more slowly in bimolecular processes.The relevance of these results to RF discharge chemistry is discussed.
- Henis, Neil B. H.,Miller, Larry L.
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p. 2820 - 2823
(2007/10/02)
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- Stereoselective Cyanation of Vinyl Halides Catalyzed by Tetracyanocobaltate(I)
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Tetracyanocobaltate(I), 3-, which is formed in an aqueous alkaline solution under a hydrogen atmosphere, catalyzes the cyanation of vinyl halides to form 2-alkenenitriles.The reaction is stereoselective, forming nitriles with retention of configuration, except for (Z)-2-bromobut-2-ene, which forms a mixture of nearly equimolar isomeric nitriles.Reactivity is dependent on the CN:Co ratio and is highest when the ratio is slightly lower than 5:1.Presence of excess cyanide ion inhibits the reaction, but a dropwise addition of the KCN solution to maintain CN:Co3-, were detected as intermediates by 1H and 13C NMR spectroscopy, indicating that the reaction proceeds stepwise.In the first step, the ? complex is formed by the oxidative addition of a vinyl halide to 3- via a radical nonchain process; in this step stereoselectivity is determined.In the second step, which is rate determining, a 2-alkenenitrile is formed by the reductive coupling of the vinyl and cyano ligands, regenerating 3-.Clear NMR evidence has been obtained for the formation of 3-, where the olefin is (E)- or (Z)-cinnamonitrile.A high degree of electron transfer from 3- to olefin was indicated by the large upfield shifts of the olefinic carbon atom resonances by coordination.
- Funabiki, Takuzo,Hosomi, Hiroaki,Yoshida, Satohiro,Tarama, Kimio
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p. 1560 - 1568
(2007/10/02)
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- Production of Acrylonitrile and Other Unsaturated Nitriles from Alkenes and Alkynes
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Passage of unsaturated organic molecules trough a 13.56-MHz radio-frequency discharge, in the presence of cyanogen, results in the formation of unsaturated nitriles.Acrylonitrile was the major product from ethylene, propylene, acrolein, methyl vinyl ketone, or 1,1,1-trifluoropropylene. 1-Butene, 2-butene, and isobutylene gave mixtures of nitrile products with the CN situated at vinylic or allylic positions. 2-Butyne gave 1-cyanopropyne.Other compounds gave only low yields of nitriles and considerable polymer.The effects of power, pressure, flow rate, and ratios of reactants on the yields of acrylonitrile from propylene and cyanogen were studied.A typical power yield of acrylonitrile was 30 g kW-1 h-1.Maximum material yields of nitrile products were obtained at intermediate powers and pressures.The products are consistent with a reaction scheme involving attack of initially formed cyano radicals on the organic substrate.This step forms activated radical intermediates, which decay through elimination of an atom or group.The atom or group which is most weakly bound is preferentially lost.
- Henis, Neil B.,Miller, Larry L.
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p. 2526 - 2529
(2007/10/02)
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- N-Trifluoroacetylimidazoles as a Reagent for Converting Aldoximes into Nitriles under Mild Conditions
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It was found that N-trifluoroacetylimidazole was an excellent reagent for the intramolecular dehydration of aldoximes to give nitriles under mold conditions.
- Keumi, Takashi,Yamamoto, Takayoshi,Saga, Hiroshi,Kitajima, Hidehiko
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p. 1579 - 1580
(2007/10/02)
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