- Preparation of cyclic ketones
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Cyclic ketones, notably cyclopentanone and 2,2-dimethylcyclopentanone, are simply, economically and efficiently prepared, even on an industrial scale, by decarboxylating/cyclizing a dicarboxylic acid, in liquid phase, in the presence of a catalytically effective amount of a metal or compound thereof selected from among boron, aluminum, gallium, indium, thallium, tin, antimony, bismuth, molybdenum, rubidium, cesium and vanadium.
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- Organothallium compounds. Reaction of phenylhydrazine with thallium(III) oxide
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Phenylhydrazine reacts with thallium(III) oxide in benzene to give organothallium compounds. Reactions of these compounds with acids afford diphenylthallium salts.
- Gun'kin
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p. 824 - 825
(2007/10/03)
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- THALLIUM AND MERCURY IN PYRROLE CHEMISTRY. USE OF C-THALLIATED AND C-MERCURIATED PYRROLE DERIVATIVES FOR SELECTIVE RING FUNCTIONALISATIONS via ipso-DETHALLIATION AND -DEMERCURIATION REACTIONS
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The use of C-thalliated and C-mercuriated pyrroles to achieve selective introduction of various functional groups in a β position is described.High yields of hardly accessible pyrrole derivatives (such as nitropyrrole) can thus be obtained.
- Monti, Donato,Sleiter, Giancarlo
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p. 771 - 774
(2007/10/02)
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- Synthesis and Structure of C5Me5Pd(PR3)X: Palladium Complexes with an Unsymmetrically Bonded Pentamethylcyclopentadienyl Ring
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THe complexes C5Me5Pd(PR3)X (1-4) are prepared from 2(μ-OCOCH3)2 and TlCl5Me5.Attempts to replace the halide ligand by a second C5Me5 or a C5H5 unit remained unsuccessful.The X-ray structure analysis of C5Me5PdCl (3) indicates that the five-membered ring shows a tendency of η1-bonding towards the metal. - Keywords: Pentamethylcyclopentadienylpalladium Complexes, Synthesis, Crystal Structure, Bonding Mode
- Kraus, H.-J.,Werner, H.,Krueger, C.
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p. 733 - 737
(2007/10/02)
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- Reactions of Monomethylthallium Diacetate and Amines
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Decomposition of MeTl(OAc)2 (Me = CH3, HOAc = CH3COOH) in methanol in the presence of amines, like 2-, 3- and 4-picoline, benzylamines, dimethylaniline causes mainly N-methylation; the concurring O-methylation of acetate, giving MeOAc, is only a minor importance.The rate of N-methylation increases in the series 2-picoline /= pyridine 3-picoline 4-picoline /= dimethylaniline /= dimethylbenzylamine.Picolinic acid and MeTl(OAc)2 (molar ratio 1:1) react to give 25percent N-methylpicolinic acid and 75percent MeOAc; when the molar ratio was at least 2:1, a 1:1 mixture of N-methylpicolinic acid and the methylester of picolinic acid was produced.These results and rate changes in different solvents are explained by assuming MeTlOAc(+) being the active methylthallium electrophile. - Keywords: Monomethylthallium Diacetate, Amines, Methylation, Reaction Rate
- Knips, Ulrich,Huber, Friedo
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p. 434 - 436
(2007/10/02)
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- Reactions of Thallium(III) Carboxylates with Ketones
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In the reaction of ketones RCOCH3 (R = CH3, C2H5, n-C3H7, i-C3H7, n-C4H9, i-C4H9, tert-C4H9) with thallium(III) acetate in methanol, thallation at CH3 or at α-C in R has been observed by NMR spectroscopy.J(203/205Tl-1H) in RCOCH2X is nearly independent of R (ca. 1290 Hz), but in R'CHXCOCH3 (R' = H, CH3, C2H5) it increases with increasing chain length.RCOCH2X and R'CHXCOCH3 decompose to give the corresponding acetoxylated ketones, e.g.CH3COCH2OCOCH3.Analogous thallation products have been observed in the reaction of acetone and C2H5COCH3 with thallium(III) iso-butyrate. - Keywords: Thallation, Ketones, Thallium(III) Acetate, Thallium(III) iso-Butyrate
- Vollmerhaus, Mechthild,Huber, Friedo
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p. 141 - 143
(2007/10/02)
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