38729-11-2Relevant articles and documents
Separation of Closely Boiling Isomers and Identically Boiling Isotopomers via Electron-Transfer-Assisted Extraction
Stevenson, Cheryl D.,McElheny, Daniel J.,Kage, David E.,Ciszewski, James T.,Reiter, Richard C.
, p. 3880 - 3885 (1998)
Mixtures of isotopomers with identical molecular weights (ethyl-d5-benzene + ethylbenzene-d5 and tert-butyl-d9-biphenyl + tert-butylbiphenyl-d9) have been partially resolved by making use of their differing solu
Room temperature iron catalyzed transfer hydrogenation usingn-butanol and poly(methylhydrosiloxane)
Coles, Nathan T.,Linford-Wood, Thomas G.,Webster, Ruth L.
supporting information, p. 2703 - 2709 (2021/04/21)
Reduction of carbon-carbon double bonds is reported using a three-coordinate iron(ii) β-diketiminate pre-catalyst. The reaction is believed to proceedviaa formal transfer hydrogenation using poly(methylhydrosiloxane), PMHS, as the hydride donor and a bio-alcohol as the proton source. The reaction proceeds well usingn-butanol and ethanol, withn-butanol being used for substrate scoping studies. Allyl arene substrates, styrenes and aliphatic substrates all undergo reduction at room temperature. Unfortunately, clean transfer of a deuterium atom usingd-alcohol does not take place, indicating a complex catalytic mechanism. However, changing the deuterium source tod-aniline gives close to complete regioselectivity for mono-deuteration of the terminal position of the double bond. Finally, we demonstrate that efficient dehydrocoupling of alcohol and PMHS can be undertaken using the same pre-catalyst, giving high yields of H2within 30 minutes at room temperature.
Photocatalytic transfer hydrogenolysis of aromatic ketones using alcohols
Gao, Zhuyan,Han, Jianyu,Hong, Feng,Lei, Lijun,Li, Hongji,Liu, Huifang,Luo, Nengchao,Wang, Feng
, p. 3802 - 3808 (2020/07/09)
A mild method of photocatalytic deoxygenation of aromatic ketones to alkyl arenes was developed, which utilized alcohols as green hydrogen donors. No hydrogen evolution during this transformation suggested a mechanism of direct hydrogen transfer from alcohols. Control experiments with additives indicated the role of acid in transfer hydrogenolysis, and catalyst characterization confirmed a larger number of Lewis acidic sites on the optimal Pd/TiO2 photocatalyst. Hence, a combination of hydrogen transfer sites and acidic sites may be responsible for efficient deoxygenation without additives. The photocatalyst showed reusability and achieved selective reduction in a variety of aromatic ketones.
Chain-selective and regioselective ethylene and styrene dimerization reactions catalyzed by a well-defined cationic ruthenium hydride complex: New insights on the styrene dimerization mechanism
Lee, Do W.,Yi, Chae S.
body text, p. 3413 - 3417 (2010/09/17)
The cationic ruthenium hydride complex [(η6-C 6H6)(PCy3)(CO)RuH]+BF 4- was found to be a highly regioselective catalyst for the ethylene dimerization reaction to give 2-butene products (TOF = 1910 h -1, >95% selectivity for 2-butenes). The dimerization of styrene exclusively produced the head-to-tail dimer (E)-PhCH(CH3)CH=CHPh at an initial turnover rate of 2300 h-1. A rapid and extensive H/D exchange between the vinyl hydrogens of styrene-d8 and 4-methoxystyrene was observed within 10 min without forming the dimer products at room temperature. The inverse deuterium isotope effect of k H/kD = 0.77 ± 0.10 was measured from the first-order plots on the dimerization reaction of styrene and styrene-d 8 in chlorobenzene at 70 °C. The pronounced carbon isotope effect on both vinyl carbons of styrene as measured by using Singletons method ( 13C(recovered)/13C(virgin) at C1 = 1.096 and C2 = 1.042) indicates that the C-C bond formation is the rate-limiting step for the dimerization reaction. The Eyring plot of the dimerization of styrene in the temperature range of 50-90 °C led to ΔH? = 3.3(6) kcal/mol and ΔS? = -35.5(7) eu. An electrophilic addition mechanism has been proposed for the dimerization of styrene.
Synthesis of Some Deuterated Aromatic Mesomorphic Compounds Used in Broad-Line 2H-NMR Studies
Neubert, Mary E.
, p. 327 - 374 (2007/10/02)
Twenty-one deuterated mesogens of the following types: HOAB (perdeuterated chains), 4-alkoxybenzoic acids (perdeuterated chain and acid deuteron), 7S5 and 8S5 (perdeuterated alkoxy chain), 4-alkoxybenzylidene-4'-alkylanilines (2 or 4 deuterons in the aniline ring, 2-α-deuterons on the alkyl chain and perdeuterated alkyl or alkoxy chain) and TBBA (perdeuterated alkyl chains or anil deuterons) were prepared for use in broad-line 2H-NMR by using standard literature methods.The required 4-alkoxybenzoic acids, aldehydes and anilines with perdeuterated chains were prepared by alkylation of the appropriate 4-substituted phenol.The acid proton in the 4-alkoxybenzoic acids were replaced with a deuteron either by basic hydrolysis of the ester or acid chloride or by base-catalyzed exchange on the acid.Two deuterons were incorporated into the aniline ring ortho to the amino group by exchange in dilute H2SO4.Four ring deuterons, two α-chain deuterons or a perdeuterated chain were incorporated into 4-alkylanilines by the following sequence of steps: Friedel-Crafts acylation of benzene with an acid chloride, catalytic reduction, Friedel-Crafts acylation with oxalyl chloride, hydrolysis in base and a Schmidt rearrangement in H2SO4.New deuteration equipment was designed for the catalytic reduction using deuterium.IR NMR and MS were used to determine the deuterium content of these compounds.Small differences in mesophase transition temperatures were observed for mesogens containing perdeuterated alkyl or alkoxy chains.
