- ELECTROCHEMISTRY AND REVERSE PULSE POLAROGRAPHIC DETERMINATION OF 1,2-DIBROMO-2,4-DICYANOBUTANE.
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The electrochemical reduction of the antibacterial agent 1,2-dibromo-2,4-dicyanobutane (DBDCB, Tektamar) at mercury electrodes in actonitrile is investigated by a variety of techniques. Reverse pulse voltammetry shows that the stoichiometry of this two-electron reduction requires the liberation of two bromide ions and an organic product of composition C//6N//2H//6 per molecule of reactant. An electroanalytical method for the determination of DBDCB based on reverse pulse polarography is described and used to determine the solubility of DBDCB in water. The solubility of DBDCB in water calculated from five analyses is 0. 164% (standard deviation 0. 010%) for a 5-ms pulse time or 0. 158% (standard deviation 0. 004%) for a 50-ms pulse time.
- Wojciechowski,Osteryoung
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- Practical and scalable preparation of 2-methyleneglutaronitrile via an efficient and highly selective head-to-tail dimerization of acrylonitrile catalysed by low-loading of tricyclohexylphosphine
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By carefully evaluating the effect of solvent, ligand, temperature, and time, the commercially available tricyclohexylphosphine was found to be a particularly effective catalyst for head-to-tail dimerization of acrylonitrile, providing an efficient, scalable, and highly selective method for preparation of the useful 2-methyleneglutaronitrile with a low catalyst loading. the Partner Organisations 2014.
- Yu, Lei,Wang, Jun,Zhang, Xu,Cao, Hongen,Wang, Genlin,Ding, Kehong,Xu, Qing,Lautens, Mark
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- Me3P-catalyzed addition of hydrogen phosphoryl compounds P(O)H to electron-deficient alkenes: 1 to 1 vs 1 to 2 adducts
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Trimethyl phosphine was used as an efficient catalyst for the addition of P(O)-H compounds to electron-deficient alkenes. The addition reactions were generally conducted using a catalytic amount of Me3P under mild reaction conditions. Both 1 to 1 and 1 to 2 adducts were obtained.
- Huang, Tian-Zeng,Chen, Tieqiao,Saga, Yuta,Han, Li-Biao
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p. 7085 - 7093
(2017/11/13)
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- Acrylonitrile dimerization preparation 2-methylene-glutaronitrile (MGN) method (by machine translation)
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The invention relates to the dimerization of acrylonitrile preparation 2-methylene-glutaronitrile (MGN) method. The method uses ion liquid [Emim]BF 4 (1-methyl-3-ethyl imidazole terafluoroborate) and its analogs as reaction medium, in acrylonitrile and the ionic liquid volume ratio (the 50 [...] 1) - (the 10 [...] 1), ionic liquid and catalyst c (alkyl/aryl) diphenylphosphinobiphenyl, such as triphenylphosphine the weight ratio of (the 1 [...] 8) - (the 5 [...] 8), reaction temperature 30-70°C, reaction time 8-24h under the condition of, acrylonitrile directional dimerization synthetic MGN, can reach the reaction yield 90.7%. This method is characterized in that the reaction system is a homogeneous catalyst, the activity of the catalyst is high, the product is easy to separate, and the ionic liquid can be recycled for a plurality of times, the production cost is low. (by machine translation)
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Paragraph 0012; 0013
(2017/06/03)
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- Hydrocyanation method for ethylenically unsaturated organic compounds
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The invention concerns a method for hydrocyanation of ethylenically unsaturated organic compounds into compounds comprising at least a nitrile function. More particularly, it concerns a method for hydrocyanation of organic compounds comprising at least a ethylenical bond by reacting hydrogen cyanide, in the presence of a catalytic system comprising a transition metal and an organophosphorus ligand. The organophosphorus ligand is a compound with monophosphanorbornadiene structure. The invention concerns in particular hydrocyanation of butadiene into adiponitrile.
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- A convenient general synthesis of 3-substituted 2H-chromene derivatives
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Reactions of 2-hydroxybenzaldehydes and 2-hydroxy-1-naphthaldehydes with various activated alkenes under Baylis-Hillman conditions have been shown to proceed with regioselective cyclisation to afford the corresponding 3-substituted chromene derivatives. In some cases competitive dimerisation of the alkene component was observed, and direct dimerisation in the absence of the aldehyde has been explored.
- Kaye, Perry T.,Nocanda, Xolani W.
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p. 1318 - 1323
(2007/10/03)
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- The kinetics and mechanism of the phosphorus-catalysed dimerisation of acrylonitrile
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Isopropyl diarylphosphinites (Ar2POPri) catalyse the dimerisation of acrylonitrile (AN) to a mixture of cis- and trans-1,4-dicyanobut-1-ene (cis,trans-DCB-1), trans-1,4-dicyanobut-2-ene (DCB-2) and 2,4-dicyanobut-1-ene (MGN). The kinetics and mechanism of the reaction, which is a potential source of hexamethylenediamine, are reported in detail and the factors which govern rate and selectivity to DCB-1 and DCB-2 rather than MGN are elaborated.
- Hall, C. Dennis,Lowther, Nicholas,Tweedy, Bruce R.,Hall, Adam C.,Shaw, Gordon
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p. 2047 - 2054
(2007/10/03)
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- Ruthenium-mediated selective head-to-tail dimerization of acrylic and α,β-unsaturated carbonyl compounds: Generation of an acrylate-hydride complex C5Me5Ru(PCy3)(CH2=CHCO 2Et)H
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The ruthenium-hydride complex C5Me5Ru(PCy3)H3 (1a) was found to be a selective catalyst precursor for the head-to-tail dimerization of acrylic and α,β-unsaturated carbonyl compounds to produce bifunctional 1,5-dicarbonyl compounds. A new ruthenium species C5Me5Ru(PCy3)(CH2=CHCO 2Et)H (6a) was independently generated from the substitution reaction of 1a with ethyl acrylate. The exclusive formation of the head-to-tail dimers suggested that, the tertiary phosphine, generated from the substitution reaction of 6a with an olefin, was the active species for the dimerization reaction.
- Yi, Chae S.,Liu, Nianhong
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p. 157 - 161
(2007/10/03)
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- The kinetics and mechanism of the phosphorus-catalysed dimerisation of acrylonitrile
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The kinetics and mechanism of the phosphinite-catalysed dimerisation of acrylonitrile to 1,4-dicyanobut-1-ene and 2,4-dicyanobut-1-ene are presented and discussed.
- Hall, C. Dennis,Lowther, Nicholas,Tweedy, Bruce R.,Kayhanian, Robert,Piffl, Michaela,Shaw, Gordon
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p. 521 - 524
(2007/10/03)
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- The Baylis-Hillman Reaction: A Novel Method for the Synthesis of α-Methylene-β-hydroxy Ketones and 2-Methylene-1,5-diketones
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A variety of α-methylene-β-hydroxyalkanones and 2-methylene-1,5-diketones were synthesized via the BAYLIS-HILLMAN reaction, i.e., the DABCO-catalyzed coupling of methyl vinyl ketone with aldehydes and dimerization of vinylic ketones respectively.
- Basavaiah, Deevi,Gowriswari, Vellanki V. L.,Dharma Rao, Polisetti,Bharathi, Tirumala K.
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p. 1656 - 1673
(2007/10/02)
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- Nucleophile-Catalysed Additions of Aldehydes and Ketones to Acrylic Compounds: The Effectiveness of High Pressures
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The preparation of a wide range of compounds of general type: CH2=C(Z)-CR1R2OH (Z = CN, COOR, CHO,; R1,R2 = H, alkyl, aryl) from the reaction of CH2=CHZ with aldehydes and ketones, is effectively catalysed by tertiary amines especially DABCO.Rates are found to be very strongly accelerated by high pressures (2-10 kbar) which alone permits the additions of ketones or of crotonic acid derivatives to take place.In the absence of carbonyl acceptors novel oligomers of acrylic compounds form.
- Hill, Jon S.,Isaacs, Neil S.
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p. 2641 - 2676
(2007/10/02)
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- DABCO Catalyzed Dimerization of α,β-unsaturated Ketones and Nitriles
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α ,β-Unsaturated ketones dimerize in the presence of catalytic amount of 1,4-diazabicyclooctane(DABCO) to produce the corresponding 2-methylene-1,5-diketones in good yields.Acrylonitrile provides the corresponding dimerized product.
- Basavaiah, D.,Gowriswari, V.V.L.,Bharathi, T.K.
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p. 4591 - 4592
(2007/10/02)
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- Reactions of Cyclopropenes, VII. Nickel(0)-catalyzed Cotrimerisation of 3,3-Dimethylcyclopropene with Methyl Acrylate
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The cotrimerisation of 3,3-dimethylcyclopropene (1) with methyl acrylate is catalyzed by phosphane- or phosphite-Ni(0) compounds under mild conditions (40 - 50 deg C).Depending on the nature of the phosphane or phosphite 1 and methyl acrylate cotrimerise mainly in the ratio 2 : 1 or 1 : 2 to give cis/trans-5 or cis/trans-6 and cyclic cis/trans-7. trans-5 and trans-6 are thermally more labile than the corresponding cis compounds.Heating to 200 deg C for two hours induces their complete rearrangement to 12 and 13 or 14 via 1,5-homodienylhydrogen shift.
- Binger, Paul,Brinkmann, Axel,Wedemann, Petra
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p. 3089 - 3101
(2007/10/02)
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- ACTIVATION OF WATER MOLECULES - 2. GENERATION OF STRONG HYDROXO BASES BY THE REACTION OF WATER WITH PLATINUM (0) PHOSPHINE COMPLEXES AND THE APPLICATIONS AS CATALYSTS FOR H-D EXCHANGE AND HYDRATION REACTIONS.
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The dissociation of Pt(PEt//3)//4 in organic solvents (THF, n-heptane) occurs to give Pt(PEt//3)//3 L equals 0. 5 M in THF at 20 degree C), no further dissociation being detected, while Pt left bracket P(i-Pr)//3 right bracket //3, upon dissolution in the above solvents, exists mainly as Pt left bracket P(i-Pr)//3 right bracket //2 (K//L equals 0. 14 M in THF at 20 degree chemical Addition of water to PtL//(L equals PEt//3//, P(i-Pr)//3) generates strong hydroxy bases, left bracket PtHL//3 right bracket OH (L equals PEt//3) or trans- left bracket PtH(S)L//2 right bracket OH (L equals P(i-Pr)//3//, S equals solvent), while the addition to Pt left bracket P(i-Pr)//3 right bracket //2 gives a sigma -hydrido hydroxo compound, trans-PtH(OH) left bracket P(i-Pr)//3 right bracket //2. Quantitative study on the reversible water addition to PtL//3 in organic solvents was carried out by pH and conductance measurements. The conductometric behaviors of the system PtL//3(L equals PEt//3)/H//2O in pyridine and THF are described in terms of two equilibria. The mechanism was studied for H-D exchange of C//6H//5COCH//3 to show that the reaction follows a rate equation, R equals k left bracket Pt right bracket left bracket C//6H//5COCH//3 right bracket , and involves a reversible condensation, M** plus OD** minus plus C//6H//5COCH//3 reversible reaction MCH// 2COC//6H//5 plus DHO, as the rate-determining step. Unlike the alkaline base-catalyzed reaction, alpha -olefinic, allylic, and aldehydic hydrogen atoms of alpha , beta -unsaturated carbonyl compounds were exchanged. The hydration of the nitrile and double bonds of RCH equals CHCN catalyzed by left bracket PtHL//3 right bracket OH or left bracket PtH(S)L//2 right bracket OH and trans-Pt(OH)(R)(PPh//3)//2 occurs with excellent chemical yields.
- Yoshida,Matsuda,Okano,Kitani,Otsuka
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p. 2027 - 2038
(2007/10/05)
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