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A series of α-diazo carbonyl compounds tethered to cyclopentanone/cyclohexanone/1-tetralone units have been synthesized using a diazomethane solution to construct various fused cyclooctane ring sys...

Heterogenized cluster complex [Pt3(CO)6]52− and reduced platinum metal have catalyzed cyclooctane dehydrogenation at comparable rates, whereas dehydrogeno-aromatization of ethylcyclohexane proceeded predominantly with the latter. Active-site ensembles for the formation of cyclooctene, bicyclooctane and aromatics were discussed on reference to the appropriate stretch of platinum metal atoms.

Three isomeric cyclooctadienes (1,5-, 1,4-, and 1,3-COD) were hydrogenated with phenylacetaldehyde (PAA)- or carbon monoxide (CO)-treated palladium black in tetrahydrofuran at 25 °C and atmospheric pressure of hydrogen. A complete depression of the hydrogenation of cyclooctene (COE) to cyclooctane (COA) was attained with both of the poisoned catalysts. By PAA the hydrogenation of 1,5-COD to COE was not hindered and the isomerization of 1,5-COD to 1,4-COD was greatly promoted, while the rate of hydrogenation of 1,4- and 1,3-COD decreased in the presence of PAA. By CO the hydrogenation and isomerization of 1,5-COD, as well as the hydrogenation of 1,4- and 1,3-COD, was suppressed. In the hydrogenation of 1,5-COD the PAA-treated palladium was more active and selective than was the CO-treated palladium for the formation of COE. The differences in the effects of these catalyst poisons are discussed on the basis of kinetic data concerning the individual and competitive hydrogenation of the three isomeric cyclooc...

Heterogenized ruthenium cluster, prepared thermally from Ru3(CO)12 and high-surface active carbon in cyclohexane, exhibited catalytic activity for cyclooctane dehydrogenation under boiling and refluxing conditions (13.6 turnovers/Ru-metal (24 h)). A half of the CO ligands was resided as [Ru(CO)2X2]n according to IR spectroscopy. The catalytic role of the trinuclear cluster dispersed on the carbon support is discussed on reference to fitness of its molecular size with the micropore diameter.

The complex formation of α-, β-, and γ-cyclodextrins (CyDs, hosts) with five cycloalkanes (guests), cyclo(pentane, hexane, heptane, octane, and decane), has been studied in aqueous media at 25°C by making use of the volatilization rate of guest molecules from the aqueous into gas phase. In the excess of the host, α-CyD forms both 1 : 1 and 2 : 1 (host: guest) complexes, while β- and γ-CyDs form 1 : 1 complexes with an exception that β-CyD forms a 2 : 1 complex with cylodecane. The 2 : 1 complex formation constants of α-CyD with cyclo(hexane, heptane, octane, and decane), particularly with cyclooctane, are extremely large compared with their 1 : 1 formation constants. The host–guest spatial fitting models are proposed.

Under boiling and refluxing conditions, cyclooctane has been dehydrogenated to cyclooctene and molecular hydrogen selectively with carbon- and alumina-supported Pd, Ph, and Ru catalysts. The activity order among these metal catalysts was Pd>Rh>Ru. The most active carbon-supported Pd catalyst was least sensitive to the rate retardation caused by cyclooctene adsorption. Desorption of molecular hydrogen from the Pd catalyst surface was deduced to proceed rapidly after the rate-determining step.

High conversions are achieved in photo-assisted dehydrogenation of alkane catalyzed by RhCl(CO)(PMe3)2 using bulky hydrocarbons like 2,2,5,5-tetramethylhexane and 1,3,5-tri-t-butylbenzene as inert solvents. Main by-product in cyclooctane dehydrogenation at a high conversion is 1,3-cyclooctadiene.

Cyclopentane, cyclohexane, cycloheptane, and cyclooctane were reacted in a radiofrequency plasma containing oxygen to give mixtures of the corresponding cycloalkanones and cycloalkanols. Tetralin was also oxidized to 1-tetralone and 1-tetralol. Based on the effects of reaction variables on the oxidation rate, the reaction scheme involving the autoxidation of cycloalkyl radicals was proposed.

α-Methylene-γ-lactone fused to cycloheptane ring was synthesized by intramolecular cyclization of 8-(ethoxycarbonyl)- or 8-(acetoxymethyl)-9-(trimethylsilyl)non-7-enoyl chloride followed by lactonization. α-Methylene-γ-lactone fused to cyclooctane and cyclotetradecane ring were also synthesized from 9-(acetoxymethyl)-10-(trimethylsilyl)dec-8-enoyl chloride and 15-(acetoxymethyl)-16-(trimethylsilyl)hexadec-14-enoyl chloride, respectively.

Photoirradiation on an A-frame dinuclear complex Ir2(μ-S)(CO)2(dppm)2 caused catalytic dehydrogenation of cyclooctane, where effectiveness was proved for all the absorption bands in the visible region (λmax: 360, 418, and 520 nm).

Alkanes are catalytically dehydrogenated to alkenes with RhCl(CH2=CH2)(PMe3)2 (λmax 416 nm) under visible light irradiation in the presence of ethylene. The reaction proceeds smoothly even at room temperature; the quantum yield of cyclooctane dehydrogenation was 0. 10 at 25 °C.

Aldehydes are effectively reduced to corresponding alcohols at room temperature using alkane as a hydrogen donor by the catalysis of RhCl(CO)(PMe3)2 under irradiation. Chemoselective reduction of aldehyde in the presence of ketone is achieved.

Heating of a solution of uracils containing diacyl peroxides such as benzoyl peroxide, lauroyl peroxide, and 2,4-dichlorobenzoyl peroxide in 1,4-dioxane at 80 °C under nitrogen atmosphere yielded 5-(2,5-dioxanyl)uracils. Similar treatments of uracils in cyclohexane, cyclooctane, ethyl acetate, 1,2-diacetoxyethane, tert-butyl acetate, and acetonitrile gave the corresponding 5-alkyluracils.

The titled catalyst systems were found to be active and convenient for the hydrogenation of olefins and to be selective toward 1,3-COD. The catalyst was transformed to some extent during the hydrogenation of 1,3-COD: cyclooctene was formed preferentially and thereafter was hydrogenated to cyclooctane successfully.

シクロアルカン類は光の存在下で塩化ニトロシルと反応して相当するシクロアルカノンオキシム塩酸塩を与えるが,このような光ニトロソ化反応におけるシクロヘキサン,シクロオクタン,シクロドデカンの反応挙動を比較検討した。シクロドデカンの場合は適当な溶媒の選択が重要であるが,シクロヘキサン(あるいはシクロオクタン)を溶媒として両者の混合反応を行なうことにより良好な結果を得た。また,これらの混合反応においてオキシム生成量の比を求めてシクロアルカンの反応性を比較した。(C8>C6≧C12)。

The title complex, [Cu(daco)2](NO3)2, was newly obtained, and found to show a characteristic reversible thermochromism. Its color changes from orange to violet on heating at 90°C, and becomes orange again on cooling. The mechanism of this thermochromism is suggested on the basis of the UV-visible reflectance spectra, and IR and TG-DTA data.