- Bis(allyl)aluminum cation, tris(allyl)aluminum, and tetrakis(allyl) aluminate: Synthesis, characterization, and reactivity
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Cationic, neutral, and anionic aluminum allyl compounds were synthesized, and their reactivity toward electrophiles was studied. The THF adduct of the previously elusive tris(allyl)aluminum, [Al(η1-C 3H5)3(THF)] (1), was isolated as an oil. Protonolysis of one allyl ligand in 1 using [NEt3H][BPh4] gave the cationic bis(allyl)aluminum, a fragment of the crystalline [Al(η1-C3H5)2(THF) 3-n]+[BPh4]-·(n+1)THF (n = 0, 1) (2). Single-crystal X-ray diffraction of [Al(η1-C 3H5)2(THF)2]+[BPh 4]- (2a) revealed a tetrahedral aluminum center, while [Al(η1-C3H5)2(THF) 3]+[BPh4]- (2b) contains a trigonal-bipyramidal aluminum center with both allyl ligands in the equatorial plane. The tetrakis(allyl)aluminate K+[Al(η1-C 3H5)4]- (3) was also synthesized from the reaction of 1 with K(C3H5). Reactions of the allyl compounds 1-3 with (i) benzophenone, (ii) allyl halides C 3H5X (X = Cl, Br, I), and (iii) halogen X2 (X = Br, I) showed considerable difference with respect to the ionic charge of the aluminum allyl.
- Lichtenberg, Crispin,Robert, Dominique,Spaniol, Thomas P.,Okuda, Jun
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Read Online
- Structure–activity relationships and docking studies of hydroxychavicol and its analogs as xanthine oxidase inhibitors
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Hydroxychavicol (HC), which is obtained from the leaves of Piper betle LINN. (Piperaceae), inhibits xanthine oxidase (XO) with an IC50 value of 16.7μM, making it more potent than the clinically used allopurinol (IC50=30.7μM). Herein, a structure–activity relationship analysis of the polar part analogs of HC was conducted and an inhibitor was discovered with a potency 13 times that of HC. Kinetic studies have revealed that HC and its active analog inhibit XO in an uncompetitive manner. The binding structure prediction of these inhibitor molecules to the XO complex with xanthine suggested that both compounds (HC and its analog) could simultaneously form hydrogen bonds with xanthine and XO.
- Nishiwaki, Keiji,Ohigashi, Kanae,Deguchi, Takahiro,Murata, Kazuya,Nakamura, Shinya,Matsuda, Hideaki,Nakanishi, Isao
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p. 741 - 747
(2018/07/05)
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- Iodine-mediated rearrangements of diallylsilanes
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Diallylsilanes can be made to rearrange upon treatment with I2. Of the silanes tested, diallyldiphenylsilane showed the greatest propensity to undergo this intramolecular carbocation allylation process. After etherification of the initially for
- O'Neil, Gregory W.,Cummins, Elizabeth J.
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p. 3406 - 3409
(2017/08/11)
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- The oxidative dehydrogenation of propane from a process for the preparation of propylene
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The invention discloses a method for preparing propylene by performing oxidative dehydrogenation on propane, and relates to a method for preparing propylene. The method comprises the steps of: heating a catalyst to the temperature of 400 to 700 DEG C, keeping the temperature for 10 to 120 minutes, introducing mixed reaction gas to pass through a catalyst bed layer, and reacting to obtain the product of propylene. The mixed reaction gas propane, oxygen, hydrogen halide gas and inert gas. A small amount of hydrogen halide is introduced into the reaction system to effectively activate the propane, the selectivity of the propylene is more than 80 percent, a once through yield of the propylene is close to 50 percent, and performance of the propylene is much better than the performance of the traditional propylene which is obtained by directly dehydrogenizing and performing oxidative dehydrogenation on the propane; a reaction process is gentle, advanced oxidation for oxidative dehydrogenation of propane to prepare the propylene is greatly suppressed at the presence of halogen hydride, the selectivity of the propylene is greatly improved, and a problem of low selectivity of the propylene at high conversion rate of the propane is solved; and the hydrogen halide is recoverable and reused, energy consumption is low, the employed catalyst is a non-noble metal catalyst, and the components is remained stable during the reaction.
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Paragraph 0039-0042
(2017/04/04)
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- MgI2-Mediated Chemoselective Cleavage of Protecting Groups: An Alternative to Conventional Deprotection Methodologies
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The scope of MgI2 as a valuable tool for quantitative and mild chemoselective cleavage of protecting groups is described here. This novel synthetic approach expands the use of protecting groups, widens the concept of orthogonality in synthetic processes, and offers a facile opportunity to release compounds from solid supports. Amazing MgI2: Protecting groups have had a tremendous positive impact on the art of biomolecule synthesis. In a context in which the use of attractive protecting groups is often limited by harsh deprotection conditions and low chemoselective flexibility, MgI2 offers, by the execution of a very simple protocol, a fresh vision with extensive perspectives.
- Berthet, Mathéo,Davanier, Florian,Dujardin, Gilles,Martinez, Jean,Parrot, Isabelle
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supporting information
p. 11014 - 11016
(2015/11/10)
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- Carbocations generated under stable conditions by ionization of matrix-isolated radicals: The allyl and benzyl cations
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Carbocations are crucial intermediates in many chemical reactions; hence, considerable effort has gone into investigating their structures and properties, for example, in superacids, in salts, or in the gas phase. However, studies of the vibrational structure of carbocations are not abundant, because their infrared spectra are difficult to obtain in superacids or salts (where furthermore the cations may be perturbed by counterions), and the generation of gas-phase carbocations in discharges usually produces several species. We have applied the technique of ionizing neutral compounds by X-irradiation of cryogenic Ar matrices to radicals embedded in such matrices, thus producing closed-shell cations that can be investigated leisurely, and in the absence of counterions or other perturbing effects, by various forms of spectroscopy. This Article describes the first set of results that were obtained by this approach, the IR spectra of the allyl and the benzyl cation. We use the information obtained in this way, together with previously obtained data, to assess the changes in chemical bonding between the allyl and benzyl radicals and cations, respectively.
- Misic, Vladimir,Piech, Krzysztof,Bally, Thomas
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p. 8625 - 8631
(2013/07/25)
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- Carbodeoxygenation of biomass: The carbonylation of glycerol and higher polyols to monocarboxylic acids
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Glycerol is converted to a mixture of butyric and isobutyric acid by rhodium- or iridium-catalysed carbonylation using HI as the co-catalyst. The initial reaction of glycerol with HI results in several intermediates that lead to isopropyl iodide, which upon carbonylation forms butyric and isobutyric acid. At low HI concentration, the intermediate allyl iodide undergoes carbonylation to give vinyl acetic acid and crotonic acid. Higher polyols CnH n+2(OH)n are carbonylated to the corresponding C n+1 mono-carboxylic acids. Copyright
- Coskun, Timur,Conifer, Christopher M.,Stevenson, Laura C.,Britovsek, George J. P.
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supporting information
p. 6840 - 6844
(2013/07/05)
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- Highly enantioselective copper-catalyzed alkylation of β-ketoesters and subsequent cyclization to spirolactones/bi-spirolactones
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Cu-catalyzed enantioselective alkylation of β-ketoesters using alcohols for in situ preparation of alkylating reagents is reported. A number of functionalized β-ketoesters containing a quaternary carbon stereocenter are obtained with up to 99% ee. The alkylation products derived from 2-substituted allylic alcohols or their corresponding iodides can then be converted to spirolactones, bi-spirolactones, and related chiral target products.
- Deng, Qing-Hai,Wadepohl, Hubert,Gade, Lutz H.
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supporting information; experimental part
p. 2946 - 2949
(2012/03/26)
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- PRODUCTION OF COMPOUNDS COMPRISING CF30 GROUPS
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The present invention relates to a process for the preparation of compounds containing CF3O groups using compounds containing at least one group Y, in which Y=—Hal, —OSO2(CF2)zF, —OSO2CzH2z+1 (z=1-10), —OSO2F, —OSO2Cl, —OC(O)CF3— or —OSO2Ar, to a process for the preparation of compounds containing CF3O groups using KOCF3 and/or RbOCF3, and to novel compounds containing CF3O groups, and to the use thereof.
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Page/Page column 6
(2011/04/24)
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- Microwave activation of alumina and its use as a catalyst in synthetic reactions
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Microwave irradiation is a simple and efficient method of activating gamma alumina. Alumina activated in this manner is an excellent medium in which to carry out the Diels-Alder reaction and, in conjunction with additional microwave irradiation, the Claisen rearrangement. Several 2-allylphenols formed in the Claisen rearrangement rapidly undergo ring closure on alumina to form dihydrobenzofurans demonstrating the Br0nsted acidity of the solid.
- Dadush, Eric,Green, James F.,Sease, Aaron,Naravane, Abhijit,Pagni, Richard M.,Kabalka, George W.
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experimental part
p. 120 - 123
(2010/02/28)
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- Transformation of tertiary amines into alkylating reagents by treatment with 2-chloro-4,6-dimethoxy-1,3,5-triazine. A synthetic application of side-reaction accompanying coupling by means of 4-(4,6-dimethoxy-[1,3,5] triazin-2-yl)-4-methyl-morpholin-4-ium chloride (DMTMM)
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Mild reaction conditions are described for the preparation of a number of alkyl chlorides and 2-dialkyl(aryl)amino-4,6-dirnethoxy-1,3,5-triazines by dealkylation of quaternary triazinylammonium chlorides formed as reactive intermediates in reaction of tertiary amines with 2-chloro-4,6-dimethoxy-1,3,5- triazine. The high selectivity of substitution was observed within the reactivity order of the alkyl groups: benzyl ~ allyl > methyl > n-alkyl. Studies on dealkylation of S-(-)-J-dimethyl-(1-phenylethyl)amine to R-(+)-1-chloro-1-phenylethane revealed that reaction proceeded with an inversion of configuration on the carbon atom as may be expected for SN2 type substitution. The scope of reaction was extended by exchange of anion in quaternary triazinylammonium chlorides with 1-, SCN-, C6H5O-, CH3COO- followed by N-dealkylation step.
- Kolesinska,Kaminski
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experimental part
p. 2115 - 2123
(2009/04/07)
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- Intramolecular [4+2] cycloaddition of furfurylsubstituted homoallylamines to allylhalides, acryloyl chloride and maleic anhydride
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Acylation of 4-(furyl-2)-4-R-aminobut-1-enes and 4-R-4-furfurylaminobut-1- enes with maleic anhydride, acryloyl chloride or allylhalides provided 3-aza-10-oxatricyclo[5.2.1.01.5]decenes. The tricycles are formed via an initial amide formation followed by a stereoselective exo-IMDAF (Intramolecular Diels-Alder of Furan). In case of competing cycloaddition (for compounds possessing two furan or two dienophilic moieties) the most substituted fivemembered cycle is preferably annulated. Refluxing of 4-R-4- furfurylaminobut-1-enes in acetic anhydride led to exo-3-aza-11-oxatricyclo[6.2. 1.01.6]undecenes with the pseudoequatorial substituent R-4. Treatment of 3-aza-10-oxatricyclo[5.2.1.01.5]decenes with PPA at 90-110 °C promoted cyclic ether opening, aromatization and intramolecular cyclization reactions sequence to give the corresponding tetracyclic compounds - tetrahydroisoindolo[2,1-a]quinolines and tetrahydroisoindolo[2,1-b][2] benzazepines in good yields. Unusual products of ipso-substitution in aromatic ring were obtained on cyclization of N-p-R-substituted 2-allyl-4-oxo-3-aza-10- oxatricyclo[5.2.1.01.5]dec-8-enes.
- Varlamov, Alexey V.,Boltukhina, Ekaterina V.,Zubkov, Fedor I.,Nikitina, Eugenia V.,Turchin, Konstantin F.
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p. 1479 - 1495
(2007/10/03)
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- 4-Aminophenyldiphenylphosphinite (APDPP), a new heterogeneous and acid scavenger phosphinite - Conversion of alcohols, trimethylsilyl, and tetrahydropyranyl ethers to alkyl halides with halogens or N-halosuccinimides
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A new heterogeneous phosphinite, 4-aminophenyldiphenylphosphinite (APDPP), is prepared and used for the efficient conversion of alcohols, trimethylsilyl ethers, and tetrahydropyranyl ethers to their corresponding bromides, iodides, and chlorides in the presence of molecular halogens or N-halosuccinimides. The amino group in this phosphinite acts as an acid scavenger and removes the produced acid. A simple filtration easily removes the phosphinate by-product.
- Iranpoor, Nasser,Firouzabadi, Habib,Gholinejad, Mohammad
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p. 1006 - 1012
(2007/10/03)
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- Silicaphosphine (Silphos): A filterable reagent for the conversion of alcohols and thiols to alkyl bromides and iodides
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Silicaphosphine (Silphos), [P(Cl)3-n(SiO2) n], as a new heterogeneous reagent is introduced. This reagent converts alcohols and thiols to their corresponding bromides and iodides in the presence of X2 (X=Br, I) in refluxing CH3CN in high to quantitative yields. Use of Silphos provides a highly practical method for the easy separation of the Silphos oxide byproduct by a simple filtration.
- Iranpoor, Nasser,Firouzabadi, Habib,Jamalian, Arezu,Kazemi, Foad
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p. 5699 - 5704
(2007/10/03)
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- Photolysis of 1-alkylcycloalkanols in the presence of (diacetoxyiodo) benzene and I2. Intramolecular selectivity in the β-scission reactions of the intermediate 1-alkylcycloalkoxyl radicals
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The C-C β-scission reactions of 1-alkylcycloalkoxyl radicals, generated photochemically by visible light irradiation of CH2Cl 2 solutions containing the parent 1-alkylcycloalkanols, (diacetoxy)-iodobenzene (DIB), and I2, have been investigated through the analysis of the reaction products. The 1-alkylcycloalkoxyl radicals undergo competition between ring opening and C-alkyl bond cleavage as a function of ring size and of the nature of the alkyl substituent. With the 1-propylcycloheptoxyl, 1-propylcyclooctoxyl, and 1-phenylcyclooctoxyl radicals, formation of products deriving from an intramolecular 1,5-hydrogen atom abstraction reaction from the cycloalkane ring has also been observed. The results are discussed in terms of release of ring strain associated to ring opening, stability of the alkyl radical formed by C-alkyl cleavage, and with cycloheptoxyl and cyclooctoxyl radicals, also in terms of the possibility of achieving a favorable geometry for intramolecular hydrogen atom abstraction.
- Antunes, Carla S. Aureliano,Bietti, Massimo,Lanzalunga, Osvaldo,Salamone, Michela
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p. 5281 - 5289
(2007/10/03)
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- Synthesis of epothilones, intermediates thereto and analogues thereof
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The present invention provides compounds of formula (I): as described generally and in classes and subclasses herein. The present invention additionally provides pharmaceutical compositions comprising compounds of formula (I) and provides methods of treating cancer comprising administering a compound of formula (I).
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- Synthesis of epothilones, intermediates thereto and analogues thereof
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The present invention provides compounds of formula (I): as described generally and in classes and subclasses herein. The present invention additionally provides pharmaceutical compositions comprising compounds of formula (I) and provides methods of treating cancer comprising administering a compound of formula (I).
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- Acyl iodides in organic synthesis: I. Reactions with alcohols
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Reaction of acyl iodides RC(O)I (R = Me, Ph) with alcohols R′OH (R′ = Me, Et, i-Pr, t-Bu, CH2= CHCH2, HC≡CCH2) provides in the corresponding organyl iodides R′I. Unlike that 2-chloroethanol and phenol (R′ = CH 2CH2Cl, Ph) react with RC(O)I in the same way as with acyl chlorides yielding esters RCO2R′. This reaction path occurs partially also with methanol and ethanol.
- Voronkov,Trukhina,Vlasova
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p. 1576 - 1578
(2007/10/03)
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- Reaction of arenediazonium tetrafluoroborates with diallyl ether in the presence of thiocyanate nucleophile
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3-Allyloxy-1-aryl-2-thiocyanatopropanes were prepared by reaction of arenediazonium tetrafluoroborates with diallyl ether under anionarylation conditions. Irrespective of the reactant ratio, the second allyl fragment in the diallyl ether molecule is not involved in thiocyanatoarylation; its presence does not affect the reaction regioselectivity.
- Gorbovoi,Zagrichuk,Grichshuk
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p. 755 - 757
(2007/10/03)
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- Kinetic evidence for a novel, Grob-like substitution/fragmentation mechanism for the reaction of nucleophiles with trialkylammoniomethyl halides
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Kinetic evidence is presented in favor of a concerted, bimolecular mechanism for the unusual nucleophilic substitution/fragmentation reactions of iodide ion with (halomethyl)trimethylammonium salts. The relative reactivities of allyl, ethyl and methyl groups for this Grob-like reaction are also determined. Activation parameters are presented for the thermal reactions of 1-iodo-N,N,N-trimethylmethaniminium iodide (log A = 8.7. Ea = 19.0 kcal mol-1) and 1-iodo-N-allyl-N,N-dimethylmethaniminium iodide (log A = 14.6, Ea = 25.7 kcal mol-1) in acetonitrile, the latter reaction having an observed second order rate constant 39 times larger than the former at 70 °C. The results are compared with the classic data of Hughes, Ingold and Conant for SN2 reactions of alkyl halides.
- Fletcher, Michelle O.,Zhang, Li,Vu, Quyen,Dolbier Jr., William R.
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p. 1187 - 1192
(2007/10/03)
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- The thermal desulfination of allylic sulfonyl halides
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Allylic sulfonyl halides can be generated by halogenolysis of the corresponding triorganotin sulfinates. Allylic sulfonyl bromides and iodides undergo a first order, thermal desulfination with allylic rearrangement to yield the corresponding allylic halides. The desulfination of a cyclic allylic sulfonyl bromide is stereospecific, proceeding with γ-syn bromine migration.
- King, Malcolm D.,Sue, Rodney E.,White, Rodney H.,Young, David J.
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p. 4493 - 4496
(2007/10/03)
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- Fused pyrimidine derivative, process for preparation of same and pharmaceutical preparation comprising same as active ingredient
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Disclosed is a fused pyrimidine of the formula [I] STR1 wherein R1, R2, and R3 are as defined in the specification, Y represents a linking group of the formula STR2 wherein n is an integer of from 4 to 6, STR3 wherein A is a hydrogen atom or alkyl group; and Z represents a hydrogen atom, or other substituents; or Y and Z together represent an unsubstituted or substituted alkyl, alkenyl or arylalkyl group; or a 5- to 7-member heterocyclic ring which has a nitrogen atom, and further, an oxygen or sulfur atom as a hetero atom other than the nitrogen atom, being bonded via the nitrogen atom therein to the 4-position of the pyrimidine ring of the formula (I), a 5- to 7-member unsaturated heterocyclic ring which has 1 to 3 nitrogen atoms being bonded via the nitrogen atom therein to the 4-position of the pyrimidine ring of the formula (I), or a fused biheterocyclic ring constructed with 5- or 6-membered aromatic or non-aromatic rings, which has 1 to 3 nitrogen atoms in any position, being bonded via the nitrogen atom therein to the 4-position of the pyrimidine ring of the formula (I); and m is an integer of from 1 to 3; and a pharmaceutically acceptable acid addition salt thereof, as well as a process for producing same and a pharmaceutical preparation useful for a treatment of hypoxemia associated with respiratory diseases.
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- Process for preparing N-alkylanilines and N-allylanilines catalyzed by iodides
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The present invention relates to a process for the N-alkylation and N-allylation of an aniline by bringing the aniline into contact with an alkylating or allylating agent in an organic solvent in a homogenous liquid phase in the presence of an iodide and a stoichiometric amount of non-quaternizable base.
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- Kinetics and Product Study of the Self-reaction of Allyl and Allyl Peroxy Radicals at 296 K
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The laser flash photolysis technique, coupled with UV absorption spectroscopy, has been used to investigate the UV spectra and kinetics of reactions of the allyl radical (CH2=CHCH2) and the allyl peroxy radical (CH2=CHCH2O2) at 296 K and total pressures near atmospheric.CH2=CHCH2 radicals were generated by the 193 nm photolysis of hexa-1,5-diene-N2 mixtures, or the 248 nm photolysis of allyl iodide-N2 mixtures.The 193 nm photolysis of hexa-1,5-diene-O2-N2 mixtures was used to generate CH2=CHCH2O2.The low resolution spectrum of CH2=CHCH2 was characterised in the range 210-232.5 nm.The absolute absorption cross-section near the maximum, ? (220 nm) = 5.8 +/- 0.8) * 10-17 cm2 molecule-1, calibrated relative to the loss of allyl iodide, is in good agreement with the single published determination.The observed time dependence of CH2=CHCH2 in the various chemical systems allowed measurement of rate coefficients for the following reactions 2CH2=CHCH2 (+M) -> CH2=CHCH2CH2CH=CH2 (+M) (10), CH2=CHCH2 + I (+M) -> CH2=CHCH2I (+M) (12), CH2=CHCH2 + O2 (+M) -> CH2=CHCH2O2 (+M) (7).The parameters obtained were k10 = (3.0 +/- 0.5) * 10-11, k12 = (1.6 +/- 0.6) * 10-10, and k7 = (6 +/- 2) * 10-13 cm3 molecule-1 s-1.The UV absorption spectrum of CH2=CHCH2O2, characterised in the wavelength range 210-300 nm, is typical of an organic peroxy radical, with a peak cross-section of (6.2 +/- 0.9) * 10-18 cm2 molecule-1 at 235 nm.CH2=CHCH2O2 displayed second-order kinetic behaviour indicative of its removal via the self-reaction: 2CH2=CHCH2O2 -> 2CH2=CHCH2O + O2 (13a) -> CH2=CHCHO + CH2=CHCH2OH + O2 (13b).The observed rate coefficient, k13obs = (1.1 +/- 0.2) * 10-12 cm3 molecule-1 s-1, is greater than the elementary coefficient, k13, owing to secondary removal of CH2=CHCH2O2.The observed and elementary coefficients are related by the expression k13obs = (1 + α13)k13, where α13 = k13a/k13.Associated long pathlength Fourier transform infrared (FTIR) measurements of the products of the 253.7 nm initiated photo-oxidation of allyl iodide, allowed the product channels of reaction (13) to be identified and quantified, and a value of α13 = 0.61 +/- 0.07 was determined, leading to k13 = (6.8 +/- 1.3) * 103 cm-13 molecule-1 s-1.The kinetic and mechanistic data obtained for CH2=CHCH2O2, and those measured previously in this laboratory for HOCH2CH2O2, are used to infer average rate coefficients for peroxy radicals (RO2) formed in the OH-initiated oxidation of isoprene.A simple box model of the planetary boundary layer is used to demonstrate the potential impact of elevated concentrations of isoprene on ambient levels of OH, HO2, RO2, O3 and NOx.
- Jenkin, Michael E.,Murrells, Timothy P.,Shalliker, Stephen J.,Hayman, Garry D.
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p. 433 - 446
(2007/10/02)
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- RAPID SYNTHESIS OF α,β UNSATURATED IODIDES: IODINATION UNDER VACUUM WITH SOLID DIPHOSPHORUS TETRAIODIDE
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α,β unsaturated alcohols are transformed in 2-5 mn and in 70-90percent yield (> 90percent pure) into their corresponding iodides when they are allowed to react with solid P2I4 under 10-2 Torr at 85 deg C.With unsymmetrical alcohols, an allylic rearrangement always leads to the more stable iodide.
- Lasne, Marie- Claire,Cairon, Philippe,Villemin, D.
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- ZIRCONOCENE-PROMOTED STEREOSELECTIVE BICYCLIZATION OF 1,6- AND 1,7-DIENES TO PRODUCE TRANS-ZIRCONABICYCLOOCTANES AND CIS-ZIRCONABICYCLONONANES.
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The Zr-promoted bicyclization of 1,6- and 1,7-dienes can stereoselectively produce trans-zirconabicyclooctanes and cis-zirconabicyclononanes, respectively; these compounds can be readily converted into protonolysis, halogenolysis, and carbonylation products.
- Rousset, Christophe J.,Swanson, Douglas R.,Lamaty, Frederic,Negishi, Ei-ichi
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p. 5105 - 5108
(2007/10/02)
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- SYNTHESIS AND REACTIVITY OF DIETHYL PHOSPHONOMETHYLTRIFLATE
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Diethyl phosphonomethyltriflate, prepared from diethyl hydroxymethylphosphonate, readily reacts in good to excellent yields with a variety of oxygen and nitrogen nucleophiles.
- Phillion, Dennis P.,Andrew, Steven S.
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p. 1477 - 1480
(2007/10/02)
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- INVESTIGATION OF ORGANIC EQUILIBRIA. II. EFFECT OF SUBSTITUENTS ON THE HARDNESS SERIES OF ACIDS WITH AN ACCEPTING CARBON ATOM IN sp3 HYBRIDIZATION. SYMBIOSIS AND ANTISYMBIOSIS
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The ΔH0Me,H values, i.e., the changes in the standard enthalpy of the hypotetical gas-phase reactions RH + CH3X->/+ as acids.It was shown that the nature of R (primary, secondary, tertiary) has a predominant effect on the hardness, whereas the effect of functional substituents in R (at the β positions and positions more remote from the accepting atom), like the effect of the specific structural characteristics of R, is on the whole small.The effect of functional α substituents on the hardness of R+ does not obey simple relationships.The general nature of the symbiosis of the ligands, which is one of the main principles of the concept of hard and soft acids and bases, is not confirmed.Conversely, antisymbiosis was found in some of the ligands X, i.e., the system was destabilized with the accumulation of substituents of X of the same type at the given carbon atom.The constants of a series of liquid-phase equilibria of the R1X + R2Y->/1Y + R2X type were measured by direct experiments.It was shown that the state of the investigated equilibria corresponds to the predictions which can be reached on the basis of the hardness series of acids and bases derived for the gas phase.
- Bochkov, A. F.
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p. 1837 - 1848
(2007/10/02)
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- Indirect Electrochemical Reduction of Unsaturated Alcohols
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Allyl alcohlol and some of its derivatives have been reduced electrochemically by a mercury electrode to unsaturated hydrocarbons in a strongly acidic medium containing iodide.During the reaction a shift of the double bond generally occurs.The reaction involves a transformation of the alcohol to an iodide, reaction of the iodide with mercury, protonation of the organomercury compound, and reduction of the mercuric salt to mercury.Benzyl alcohols are similarly reduced to hydrocarbons.
- Lund, Torben,Lund, Henning
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p. 387 - 390
(2007/10/02)
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- SYNTHESIS OF SOME BENZIMIDAZOLES CONTAINING 2-PERFLUORO SUBSTITUENTS
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A new method is described for the preparation of 2-perfluoroalkylether-benzimidazoles through the N-monoacyl derivatives of o-phenylenediamine. 2-Pentafluorophenylbenzimidazole has been obtained by the reaction of o-phenylenediamine and pentafluorobenzoic acid in the presence of polyphosphoric acid. 2-Perfluoroalkylbenzimidazoles have been prepared in excellent yields by direct condensation of o-phenylenediamine with perfluoroalkane-carboxylic acids in the absence of any solvent or added reagent.Some derivatives of these compounds are also described.
- Eapen, Kalathil C.,Tamborski, Christ
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p. 243 - 258
(2007/10/02)
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- Reaction of Allyl Diphenyl Phosphates with Soft Bases
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The title phosphates were found to react with a variety of soft bases to give nucleophilic substitution products in high yields.The reaction proceeded regiospecifically under mild reaction conditions with preservation of the double bond geometry.
- Araki, Shuki,Minami, Kazuhiro,Butsugan, Yasuo
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p. 629 - 630
(2007/10/02)
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- Reactions of Diaryltellurides with Some Organic Halides and Sn(IV) Tetraiodide: Electrophilic Cleavage of Te-Allyl Bond
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Diaryltellurides, RTeR' (R = R' = C6H5 or p-CH3OC6H4; and R = C6H5, R' = p-CH3OC6H4) react with allyl bromide, cyclohexyl iodide, CH3I, C6H5X (X = Br, I) or SnI4 to give corresponding triorganotelluronium halides.The Te-allyl bond is readily cleved by electrophiles as Br2, I2, ICl, BrCN, ICN.
- Srivastava, T. N.,Srivastava, R. C.,Singh, Mala
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p. 435 - 437
(2007/10/02)
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- Carbon-Halogen Bonding Studies. Halogen Redistribution Reactions between Alkyl or Acetyl Halides and Tri-n-butyltin Halides
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The equilibrium positions have been determined for the halogen redistribution reactions of tri-n-butyltin halides with a variety of structurally different types of alkyl halides and with acetyl halides.These have been related through the reaction ΔGo values to carbon-halogen bond dissociation energy differences.It is suggested that the trends observed in the latter may provide evidence for the existence of a small steric bond weakening effect in the order C-I > C-Br > C-Cl bonds on going from methyl to primary, secondary, and tertiary alkyl halides.On the other hand, with the 2,3-? bond containing allyl, benzyl, and propargyl halides , α-haloacetones, and haloacetonitriles, there may be some type of electronic carbon-halogen bond strengthening effect which lies in order C-I > C-Br > C-Cl.Finally, for the acetyl halides, the data are in agreement with increases in bond strengths resulting from ? contributions being in the order C-Cl > C-Br > C-I.
- Friedrich, Edwin C.,Abma, Charles B.
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p. 1367 - 1371
(2007/10/02)
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- Catalytic Halide Exchange in Hydrocarbons Promoted by Aluminas Coated with Phosphonium Salts
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Passing a mixture of two different alkyl halides, in the gas phase, through a column filled with alumina and a phosphonium salt, gives halide-exchange products which are collected at the outlet by condensation; the process is catalytic and allows transformations to be carried out in a continuous flow process.
- Angeletti, Enrico,Tundo, Pietro,Venturello, Paolo
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p. 1127 - 1128
(2007/10/02)
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