- Electrocatalytic hydrogenation of benzoic acids in a proton-exchange membrane reactor
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The highly efficient chemoselective electrocatalytic hydrogenation of benzoic acids (BAs) to cyclohexanecarboxylic acids (CCAs) was carried out in a proton-exchange membrane reactor under mild conditions without hydrogenation of the carboxyl group. Among the investigated catalysts, the PtRu alloy catalyst was found to be the most suitable for achieving high current efficiencies for production of CCAs. An electrochemical spillover mechanism on the PtRu alloy catalyst was also proposed.
- Atobe, Mahito,Fukazawa, Atsushi,Shida, Naoki,Shimizu, Yugo
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supporting information
p. 7363 - 7368
(2021/09/08)
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- Nickel- and cobalt-catalyzed direct alkylation of azoles with N-tosylhydrazones bearing unactivated alkyl groups
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A matter of catalyst: Azole compounds can be directly alkylated with N-tosylhydrazones that bear unactivated alkyl groups (see scheme; phen=1,10-phenanthroline, Ts=p-toluenesulfonyl). Nickel catalysis enables the introduction of simple secondary alkyl chains into benzoxazole compounds, whereas the alkylation of 5-aryloxazoles and benzothiazole is possible by using a cobalt catalyst. Copyright
- Yao, Tomoyuki,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; experimental part
p. 775 - 779
(2012/02/06)
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- 5-ETHYL-IMIDAZO (5,1-F) (1,2,4,) TRIAZIN-4 (3H) -ONES AS PHOSPHODIESTERASE INHIBITORS
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The invention relates to novel 5-ethyl-imidazotriazinones, processes for their preparation and their use in medicaments, esp. for the treatment and/or prophylaxis of inflammatory processes and/or immune diseases.
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Page/Page column 35-36
(2010/02/07)
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- Separation of cis/trans-cyclohexanecarboxylates by enzymatic hydrolysis: Preference for diequatorial isomers
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4-Substituted cis/trans-cyclohexanecarboxylates have been separated into the isomers by enzymatic hydrolysis with lipase from Candida rugosa with very good selectivity. The enzyme preferentially recognizes diequatorial conformations. Copyright (C) 1996 Elsevier Science Ltd.
- Koenigsberger, Kurt,Luna, Hector,Prasad, Kapa,Repic, Oljan,Blacklock, Thomas J.
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p. 9029 - 9032
(2007/10/03)
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- Pd-Catalyzed Regio- and Stereo-selective Carboxylation of Cycloalkanes with CO
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The reactions of cycloalkanes with CO via the C-H bond activation by Pd(OAc)2 catalyst have been found to proceed regio- and stereo-selectively to give corresponding carboxylic acids.The reactivity of C-H bonds of cycloalkanes decreases in the order: tert- > sec- > prim-carbon, and the stereochemistry of the substitutents on the main products is all equatorial.
- Satoh, Ko-ichi,Watanabe, Jun,Takaki, Ken,Fujiwara, Yuzo
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p. 1433 - 1436
(2007/10/02)
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- N-(Cyclohexylcarbonyl)-D-phenylalanines and related compounds. A new class of oral hypoglycemic agents. 2
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A series of analogues of N-(cyclohexylcarbonyl)-D-phenylalanine (5) have been synthesized and evaluated for their hypoglycemic activity. Relationships were studied between the activity and the three-dimensional structure of the acyl moiety, which was characterized by high-resolution 1H NMR spectroscopy and MNDO calculations. The role of the carboxyl group of the phenylalanine moiety was also studied by comparing the activities of the enantiomers, the decarboxyl derivative, the esters, and the amides of the phenylalanine derivatives. Thus, the structural requirements for possessing hypoglycemic activity was elucidated and a highly active compound, N-[(trans-4-isopropylcyclohexyl)carbonyl]-D-phenylalanine (13) was obtained, which showed a 20% blood glucose decrease at an oral dose of 1.6 mg/kg in fasted normal mice.
- Shinkai,Nishikawa,Sato,Toi,Kumashiro,Seto,Fukama,Dan,Toyoshoma
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p. 1436 - 1441
(2007/10/02)
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- Antiprotozoal compounds
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1,4-Naphthoquinones of formula (I), methods for their preparation, veterinary formulations thereof, and the use thereof in animal therapy are disclosed. STR1 Particularly preferred compounds of formula (I) are, 2-[trans-(4-t-butylcyclohexyl)methyl]-3-hydroxy-1,4-naphthoquinone, and 2-[trans-(4-t-pentyl cyclohexyl)methyl]3-hydroxy-1,4-naphthoquinone. The compounds are of value as anti-protozoal agents, in particular as anti-theilerial agents.
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- Stereoelectronic Effects in Hydrogen-atom Transfer Reactions of Substituted Cyclohexyl Radicals
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Thermolysis of the peroxyoxalates (1)-(7) and the diacyl peroxides (8)-(11) in cyclohexane at 100 deg C gives cycloalkenes and cycloalkanes by hydrogen-atom transfer reactions of the initially formed conformationally biased 4-t-butyl-, 4-t-butyl-cis,cis-2,6-dimethyl-, 4-t-butyl-cis,trans-2,6-dimethyl-, 4-t-butyl-cis-2-methyl-, 4-t-butyl-trans-2-methyl-, and 5-t-butyl-cis-2-methylcyclohexyl radicals (12)-(17).The composition of the product mixtures indicates that transfer of axial β-hydrogen atoms occurs more rapidly than does transfer of equatorial β-hydrogen atoms.These results support the hypothesis that homolytic fission of a C-H bond is favoured when it lies chlose to the plane of an adjacent semi-occupied orbital.
- Beckwith, Athelstan L. J.,Easton, Christopher J.
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p. 661 - 668
(2007/10/02)
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- Hydrogenolyse en phase liquide des epoxydes du t-butyl-4 methylene-cyclohexane sur divers catalyseurs metalliques supportes
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Epoxides of 4-t-butylmethylenecyclohexane have been hydrogenolised on various supported metal catalysts: Pd, Pt, Rh, Ni, at ordinary temperature and 1 atm pressure in various solvents.All these catalysts present a good regioselectivity, leading to preferential cleavage of the more substituted C-O bond.In the isomerisation process the order of reactivity is Ni Pt Pd = Rh with a yield in aldehydes of 60 percent for Pd and 80 percent for Rh and an important percentage of configuration inversion.The reaction could be used as a good method for preparing cis or trans 4-t-butylcyclohexanecarboxaldehyde.On Pt and Ni, hydrogenolysis yields primary alcohols with cleavage of the oxiran ring by trans or cis addition of hydrogen.
- Accrombessi, Georges,Geneste, Patrick,Olive, Jean-Louis,Pavia, Andre Armand
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- Stereochemistry of Alkylation of Carboxylic Acid Salt and Ester α Anions Derived from Cyclic Systems.
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A stereochemical study of the alkylation of α-lithiated carboxylate salts and esters has been performed.The α anions derived from the bicyclic acids exo-1, endo-1, and 7 (R=H) and the esters 4 and 7 (R=CH3) yield predominantly exo alkylation.As an example, the α anion derived from ester 7 (R=CH3) on treatment with CH3I yields exo-8 (R=R'=CH3) and endo-9 (R=R'=CH3) in a 97:3 ratio, a highly stereoselective reaction.Addition of TMEDA to the reactions involving the α anions derived from exo- or endo-1 did not change the stereochemical alkylation results.The α anions derived from the substituted cyclohexanecarboxylic acids 10, 13, 16, 19, or 22 (where R=H in each case) on methylation yield more axial methylation (axial/equatorial ratios of 0.4-2.7) than the α anions derived from the methyl esters corresponding to these acids.The α anions from the esters yield predominantly equatorial methylated products (e/a ratios varying from 4 to 9).The reasons for the different stereochemical results are discussed.
- Krapcho, A.Paul,Dundulis, Edward A.
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p. 3236 - 3245
(2007/10/02)
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