- Triazacyclohexane chromium triflate complexes as precursors for the catalytic selective olefin trimerisation and its investigation by mass spectrometry
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A novel set of linear α-olefin trimerisation pre-catalysts is presented. The R3TACCr(OTf)3 (R3TAC = 1,3,5-trialkyl-1,3,5-triazacyclohexane) complexes produce an active system after facile activation with less than 10 equivalents of trialkylaluminium. Isomerisation was observed in many cases, which is proposed to occur via the π-allyl complex mechanism, though this was minimised by optimisation of the reaction conditions. The pre-catalysts can be synthesised from R3TACCrCl3 in neat TfOH or by addition of R3TAC to Cr(OTf)3 or better Cr(OTf)3(THF)3, the synthesis and structure of which is presented here. The use of this highly defined system allowed the identification of 2-methyl-1-hexene as a side product of activation with AlMe3, in agreement with the proposed metallacyclic mechanism. Isomer distribution of the trimer product is similar to R3TACCrCl3/MAO activated systems and depends mostly on the ligand substituent R. ESI mass spectrometry of an ortho-difluorobenzene solution of the activated catalyst was analysed at different stages of reaction. A series of signals was observed that matched those expected for cationic chromium species predicted by the metallacyclic mechanism. In particular, [R3TACCrMe2]+ was observed to form immediately after alkylation with AlMe3, while [R3TACCr(olefin)n]+ (n = 0, 1, 2, 3, 4 and olefin = 1-hexene or 1-octene) formed after addition of 1-hexene. Absence of any detected tetramer and observation of [R3TACCr(olefin)4]+ leads to the conclusion that a metallacycloheptane-olefin complex may lead to β-H abstraction rather than insertion and may even be required to avoid formation of [R3TACCr(olefin)1]+ which is observed in only very small amounts indicating a low stability. Chromium(I) complexes [R3TACCr(arene)]+ with the arene solvent can also be observed and their signal intensity indicate a relative stability of o-C6H4F2 cymene benzene PhF, toluene p-xylene.
- K?hn, Randolf D.,Coxon, Alexander G.N.,Chunawat, Samaphon,Heron, Callum,Mihan, Shahram,Lyall, Catherine L.,Reeksting, Shaun B.,Kociok-K?hn, Gabriele
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- Synthesis of new N-glycosides based on Valproic acid analogs tetrazole derivatives
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New N-glycosides based on valproic acid analogs tetrazole derivatives were synthesized. The bis-tetrazole derived from 1,6-hexandiol was also connected to acetylated glucose and formed bis-N-glycoside. Structures characterizations have been performed using FT IR, 1H and 13C NMR spectroscopy.
- Noroozi Pesyan, Nader,Ebrahimi, Marziyeh
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p. 1059 - 1067
(2017/03/11)
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- Antiviral Agents
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A compound of formula (I) and pharmaceutically acceptable salts thereof; compositions containing it and its use in medicine, particularly for the treatment or inhibition of HCV infections, and processes for making it are disclosed.
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Page/Page column 17-18
(2010/06/22)
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- Method for producing organic compounds by substituting halogen atoms
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The invention pertains to a method in which a halogen atom of an organic compound is replaced with a group derived from a nucleophilic agent, at high yield and high efficiency, by the following method which includes a step of reacting the nucleophilic agent with an organic material having a halogen atom bonded to a carbon atom having four σ bonds, more specifically: a method for producing an organic compound having Q, the method including a step of reacting a compound represented by general formula (2) with an organic starting material having at least one halogen atom bonded to a carbon atom having four σ bonds so as to replace the halogen atom in the organic starting material with Q:MQa (wherein M represents an alkali metal atom, an alkali earth metal atom, or a rare earth metal atom; Q represents a moiety of an inorganic acid or an active hydrogen compound derived by eliminating a proton, wherein Q is a halogen atom different from the halogen atom in the organic starting material having the halogen atom bonded to the carbon atom having the four σ bonds; and a represents an integer of 1 to 3) in the presence of a compound represented by general formula (1) (wherein Z- represents an anion derived by eliminating a proton from an inorganic acid or an active hydrogen compound; R2 is the same or different; R2 each independently represent a C1-C10 hydrocarbon group or two R2 on the same nitrogen atom may be bonded with each other to form a ring with the nitrogen atom).
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- Deprotonation-alkylation of alkyl cyanides under sonochemical conditions
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Deprotonation-alkylation of n-alkyl cyanides can be readily effected by an alkyl halide in the presence of sodium in a one pot procedure. Yields are generally better than in the usual methods, and the overall reaction conditions have important advantages
- Berlan,Delmas,Duee,Luche,Vuiglio
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p. 1253 - 1260
(2007/10/02)
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- Phase-Transfer Catalyzed Formation of α-Cyano Ketones from Ketone Aroylhydrazones in NaCN(aq)-Inert Organic Solvent System
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α-Cyanoalkyl aryl ketones can be obtained from ketone aroylhydrazones by heterogeneous reaction with aqueous sodium cyanide, an inert organic solvent, and acetic acid in the presence of air and a catalytic amount of a quaternary ammonium salt.The initiall
- Chiba, Toshiro,Okimoto, Mitsuhiro
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p. 6163 - 6166
(2007/10/02)
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- Process for introducing alkyl radicals into carbon chains having a functional group and compounds prepared by said process
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Process for introducing a substituent selected from branched- or straight-chain alkyl radicals having from 1 to 12 carbon atoms, aralkyl or cycloalkyl radicals in which the alkyl moiety has from 1 to 4 carbon atoms, into a carbon chain bearing a stable functional group the said carbon chain having at least one proton in α-position in relation to this functional group, process whereby, in a first step, this carbon chain is reacted with a complex base comprising a mixture of alkali metal amide and alkali metal alcoholate suspended in an anhydrous organic solvent to provide temporarily a carbanion, then in a second step this carbanion is reacted in an anhydrous organic solvent with an alkyl, aralkyl or cycloalkyl halide corresponding to the substituent to be introduced.
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- The Conversion of Aldehydes and Ketones via their 2,4,6-Tri-isopropylbenzenesulphonyl Hydrazones into Nitriles containing One Additional Carbon Atom
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2,4,6-Tri-isopropylbenzenesulphonyl hydrazones of aliphatic and alicyclic aldehydes and ketones react readily with potassium cyanide in boiling methanol solution to give the corresponding nitriles (containing one more carbon atom than the original aldehyde or ketone) in satisfactory yield. Under the same conditions, benzaldehyde 2,4,6-tri-isopropylbenzenesulphonyl hydrazone gives phenylacetonitrile in very low yield.In some cases, the arenesulphonyl hydrazones may be generated in situ, in methanol solution, from the carbonyl compounds and 2,4,6-tri-isopropylbenzenesulphonohydrazide (11a), thereby constituting a one-pot preparation or the nitriles.
- Jiricny, Josef,Orere, Daniel M.,Reese, Colin B.
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p. 1487 - 1492
(2007/10/02)
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- Process for the preparation of acetic acid derivatives
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Process for the preparation of di-n-propyl acetic acid of formula: STR1 and its non-toxic alkali and alkaline earth metal salts whereby in a single stage, sodium n-propylate in n-propanol medium is added to a reaction medium formed of a cyanacetic ester of general formula: STR2 in which R represents an alkyl radical having from 1 to 4 carbon atoms, and n-propyl bromide or iodide, the alkylation reaction taking place under reflux, the crude ester obtained is saponified with a 10 to 20% solution of sodium or potassium hydroxide, the salt thus obtained is acidified with a strong acid, to give the crude di-n-propyl cyanacetic acid, which is decarboxylated by heating at a temperature between 140° and 190° C, to provide the di-n-propyl acetonitrile, the di-n-propyl acetonitrile obtained is hydrolysed by means of an aqueous solution of 75 to 80% sulphuric acid at a temperature of 80°-140° C to give the crude di-n-propyl acetamide, which is hydrolyzed by means of an aqueous solution of 75-80% sulphuric acid at a temperature of 40°-80° C in the presence of sodium nitrite, to provide di-n-propyl acetic acid, which is caused to react, if so desired, with an alkali metal hydroxide or alkaline earth metal oxide in order to obtain the corresponding salt.
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- Some O alkylaminoalkyl thioester analogs of adiphenine and related esters
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Syntheses of nine O alkylaminoalkyl thioester analogs of the adiphenine molecule: preliminary studies of their spasmolytic activity and of their action against the state of tremor caused by oxotremorine in the mouse are described.
- Reynaud,Richard,Menard,et al.
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p. 262 - 267
(2007/10/05)
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