- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
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supporting information
(2020/07/20)
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- Triphosgene and DMAP as Mild Reagents for Chemoselective Dehydration of Tertiary Alcohols
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The utility of triphosgene and DMAP as mild reagents for chemoselective dehydration of tertiary alcohols is reported. Performed in dichloromethane at room temperature, this reaction is readily tolerated by a broad scope of substrates, yielding alkenes preferentially with the (E)-geometry. While formation of the Hofmann products is generally favored, a dramatic change in alkene selectivity toward the Zaitzev products is observed when the reaction is carried out in dichloroethane at reflux.
- Ganiu, Moshood O.,Cleveland, Alexander H.,Paul, Jarrod L.,Kartika, Rendy
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supporting information
p. 5611 - 5615
(2019/08/01)
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- NOVEL COMPOUNDS 514
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The invention provides compounds of formula (I), wherein R1, R2, R3, R4, R5, g, h and X are as defined in the specification, a process for their preparation, pharmaceutical compositions containing the
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Page/Page column 56-57
(2008/12/05)
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- QUINICLIDINE DERIVATIVES OF (HETERO) ARYLCYCLOHEPTANECARBOXYLIC ACID AS MUSCARINIC RECEPTOR ANTAGONISTS
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The invention provides compounds of formula (I) wherein R4 is a group of formula (II) or (IIIa) or (IIIb) and R1, R2, R3, R5, a, b and X are as defined in the specification, a process for their preparation, pharmaceutical compositions containing them, a process for preparing pharmaceutical compositions, their use in therapy and intermediates of use in their preparation (I), (II), (IIIa), (IIIb).
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Page/Page column 79
(2008/12/05)
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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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- Oxidative fragmentation of 1-aryl-1-cycloalkenes using cerium(IV) ammonium nitrate (CAN): Some novel observations
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1-Phenyl-1-cycloalkenes undergo oxidative fragmentation in presence of CAN in methanol, affording 1,n-dicarbonyl compounds as the major products along with 1,2-dimethoxycycloalkanes. The reaction under deoxygenated conditions afforded the latter in good yields. In the presence of azide ion, fragmentation leading to the corresponding cyanoketones was observed whereas with sulfinate only the 1-methoxy-2-sulfonyl cycloalkanes were formed.
- Nair, Vijay,Panicker, Sreeletha B,Thomas, Siji,Santhi,Mathai, Sindhu
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p. 3229 - 3234
(2007/10/03)
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- Synthesis of Certain Mesogenic Azomethines Derived from 4-Cycloalkylanilines and from 4-Cycloalkylbenzaldehydes
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General procedures are described for the synthesis of members of five pairs of related homologous series of mesogenic azomethines differing in the mode of linkage of the CH=N group and containing a cycloalkyl group in a terminal position.
- Byron, D. J.,Matharu, A. S.,Rees, M.,Wilson, R. C.
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p. 229 - 238
(2007/10/02)
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- Thermochemistry of Strained Cycloalkenes: Experimental and Computational Studies
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Pulsed time-resolved photoacoustic calorimetry in combination with quantum yield determinations afforded the relaxed triplet energy of 1-phenylcyclooctene and the energy of geometric isomerization of cis-1-phenylcyclooctene.These values are combined with
- Strickland, Alan D.,Caldwell, Richard A.
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p. 13394 - 13402
(2007/10/02)
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- Studies on the Oxidation of Phenyl Cycloalkanes by Tertiary Hydroperoxides
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During the thermal decomposition of cumene hydroperoxide at about 125 deg C in phenyl cycloalkanes as solvents, the solvents are attacked, preferably at the tertiary C-H bonds.Up to 70percent (with regard to the decomposed hydroperoxide) of oxidation products of the phenyl cycloalkanes are obtained.The main oxidation products are the corresponding 1-phenyl cycloalkanols, but relatively large amounts of phenyl alkyl ketones with the same number of carbon atoms are also formed, probably via a further oxidation of the 1-phenyl cycloalkanols.
- Pritzkow, Wilhelm,Suprun, Vladimir Ya.,Voerckel, Volkmar
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p. 381 - 386
(2007/10/02)
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- CH ACIDITY OF SUBSTITUTED CYCLOALKANES. IV. EFFECT OF THE SIZE OF THE ALKANE RING AND THE STRENGTH OF THE BASE ON THE KINETICS OF IONIZATION OF PHENYLCYCLOALKANES
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The rate constants (k) for the ionization of phenylcycloalkanes (C3-C8) were determined in solutions of lithium cyclohexylamide in cyclohexylamine and of potassium tert-butoxide and dimsylpotassium in DMSO.The dependence of k on the strength of the broken
- Zharova, N. G.,Shapiro, I. O.
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p. 598 - 602
(2007/10/02)
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- Studies on the Autoxidation of Phenyl Cycloalkanes
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The products of the autoxidation of phenyl cyclopropane (I), phenyl cyclobutane (II), phenyl cyclopentane (III), phenyl cyclohexane (IV), phenyl cycloheptane (V) and phenyl cyclooctane (VI) were analyzed after reduction of the reaction mixtures with LiAlH4.As products of the attack on the α-C-H bonds the corresponding 1-phenyl cycloalkanols and 1-phenyl alkan-1-ols were found.In the case of phenyl cyclopropane some SR2 ring opening probably takes place.The oxidabilities , the chain termination constants kt, the absolute chain propagation constants kp and the relative chain propagation constants (kp)rel were determined for the phenyl cycloalkanes I-VI.As it is to be expected on the basis of the I-strain concept the autoxidation rate of phenyl cyclopentane (III) is considerably higher than that of phenyl cyclobutane (II) and phenyl cyclohexane (IV).
- Batke, Birgit,Lauterbach, Gerlinde,Pritzkow, Wilhelm,Voerckel, Volkmar,Belyakov, Vladimir A.
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p. 424 - 430
(2007/10/02)
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- Studies on Thermal Conversion of Phenylcyclopentane, -hexane, -heptane, and -octane in the Gas Phase
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The title compounds were pyrolyzed from 700 to 780 deg C in a metallic laboratory tubular reactor in the presence of steam.The reaction products were analyzed by gas chromatography and by a combination of gas chromatography and mass spectrometry.From the phenylcyclanes tested, more than 65 hydrocarbons could be detected in the liquids, besides gaseous reaction products.In most cases unambiguous structures could be derived by using different analytical methods.As typical initial-step products phenylcyclenes, ω-phenyl-1-alkenes and 1-phenyl-1-alkenes are formed by dehydrogenation and isomerization of the title compounds.The detection of phenylalkenes corresponds well with the isomerization of unsubstituted cyclanes to the corresponding α-olefines described in former papers.
- Lam, Ho Son,Zimmermann, G.,Anders, G.,Bach, G.,Rennecke, D.,Zychlinski, W.
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p. 759 - 766
(2007/10/02)
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