1989-33-9Relevant academic research and scientific papers
Fixation of Carbon Dioxide with Diphenylcarbodiimide as a Model of Biotin Enzyme Active Site and a Weak Base: The Carboxylation of Fluorene under Mild Conditions
Chiba, Koji,Tagaya, Hideyuki,Karasu, Masa,Ono, Tsuyoyuki,Saito, Masaru,Ashikagaya, Atsushi
, p. 3738 - 3740 (1991)
Carbon dioxide was directly fixed into fluorene in the presence of diphenylcarbodiimide (DPC) as a model of a biotin enzyme active site and potassium hydrogencarbonate.It was considered that not only carbon dioxide but also the hydrogencarbonate ion were the carbon source in the presence of DPC.Weak bases such as potassium acetate, potassium propionate, and potassium formate were also effective for carboxylation.
Flash photolysis of 10-diazo-9(10H)-phenanthrenone in aqueous solution. Hydration of fluorenylideneketene and the fluorene-9-carboxylic acid keto-enol system
Andraos,Chiang,Kresge,Popik
, p. 8417 - 8424 (1997)
Flash photolysis of 10-diazo-9(10H)-phenanthrenone in aqueous solution was found to give two successively formed transient species and to produce fluorene-9-carboxylic acid as the major reaction product. These transients were identified, through solvent isotope effects and the form of acid-base catalysis, as fluorenylideneketene, formed by photo-Wolff reaction of the diazophenanthrenone, and fluorene-9-carboxylic acid enol, formed by hydration of this ketene. Analysis of the rate profile of the enol ketonization reaction produced the first and second ionization constants for the enol ionizing as an oxygen acid, pQ(a)(E) = 2.01 and pQ'(a)(E) = 9.61, respectively. The rate of enolization of fluorene-9-carboxylic acid was also determined, by bromine scavenging, and that, coupled with a literature value of the acidity constant of this acid, allowed evaluation of the two keto-enol equilibrium constants (pK(E) = 9.67 for interconverting un-ionized carboxylic acid and enol and pK'(E) = 8.24 for interconverting singly ionized acid and enol), and it also allowed evaluation of the two carbon acid acidity constants (pQ(a)(K) = 11.67 for ionization of the un-ionized carboxylic acid as a carbon acid and pQ'(a)(K) = 17.85 for ionization of its carboxylate ion as a carbon acid). (All acidity constants are concentration quotients applicable at ionic strength 0.10 M.) These keto-enol equilibrium constants and acid dissociation constants are large because of the enol and enolate ion stabilizing effects of the cyclopentadienyl ring of the fluorenyl group; this ring also makes fluorenylideneketene an unusually reactive substance.
Electrogenerated Sm(II)-Catalyzed CO2 Activation for Carboxylation of Benzyl Halides
Bazzi, Sakna,Schulz, Emmanuelle,Mellah, Mohamed
supporting information, p. 10033 - 10037 (2019/12/24)
Sm(II)-catalyzed carboxylation of benzyl halides is reported through the electrochemical reduction of CO2. The transformation proceeds under mild reaction conditions to afford the corresponding phenylacetic acids in good to excellent yields. This user-friendly and operationally simple protocol represents an alternative to traditional strategies, which usually proceeds through the C(sp3)-halide activation pathway.
CATALYST COMPONENT FOR OLEFIN POLYMERIZATION AND CATALYST CONTAINING CATALYST COMPONENT AND USE THEREOF
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Paragraph 0068, (2017/04/21)
A catalyst component for olefin polymerization, comprising Mg, Ti, a halogen and an electron donor, wherein the electron donor is at least one unsaturated ring-substituted diacid ester compound. Also provided is a catalyst containing the catalyst component and the use of the catalyst in an olefin polymerization, e.g., propylene polymerization.
CATALYST COMPONENT FOR OLEFIN POLYMERIZATION AND APPLICATION THEREOF
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Paragraph 0096, (2017/10/17)
Provided is a solid catalyst component for olefin polymerization, which comprises Mg, Ti, a halogen and an electron donor. The electron donor is selected from at least one of ring-substituted ether-acid ester compounds of the general formula (I). Also provided are a catalyst containing the solid catalyst component and the application of the catalyst in reactions of olefin polymerization, particularly in the reaction of propylene polymerization.
Ni-catalyzed carboxylation of C(sp2)- and C(sp3)-O bonds with CO2
Correa, Arkaitz,Leon, Thierry,Martin, Ruben
supporting information, p. 1062 - 1069 (2014/02/14)
In recent years a significant progress has been made for the carboxylation of aryl and benzyl halides with CO2, becoming convenient alternatives to the use of stoichiometric amounts of well-defined metal species. Still, however, most of these processes require the use of pyrophoric and air-sensitive reagents and the current methods are mostly restricted to organic halides. Therefore, the discovery of a mild, operationally simple alternate carboxylation that occurs with a wide substrate scope employing readily available coupling partners will be highly desirable. Herein, we report a new protocol that deals with the development of a synergistic activation of CO2 and a rather challenging activation of inert C(sp2)-O and C(sp3)-O bonds derived from simple and cheap alcohols, a previously unrecognized opportunity in this field. This unprecedented carboxylation event is characterized by its simplicity, mild reaction conditions, remarkable selectivity pattern and an excellent chemoselectivity profile using air-, moisture-insensitive and easy-to-handle nickel precatalysts. Our results render our method a powerful alternative, practicality and novelty aside, to commonly used organic halides as counterparts in carboxylation protocols. Furthermore, this study shows, for the first time, that traceless directing groups allow for the reductive coupling of substrates without extended π-systems, a typical requisite in many C-O bond-cleavage reactions. Taking into consideration the limited knowledge in catalytic carboxylative reductive events, and the prospective impact of providing a new tool for accessing valuable carboxylic acids, we believe this work opens up new vistas and allows new tactics in reductive coupling events.
Ni-catalyzed direct carboxylation of benzyl halides with CO2
León, Thierry,Correa, Arkaitz,Martin, Ruben
supporting information, p. 1221 - 1224 (2013/03/14)
A novel Ni-catalyzed carboxylation of benzyl halides with CO2 has been developed. The described carboxylation reaction proceeds under mild conditions (atmospheric CO2 pressure) at room temperature. Unlike other routes for similar means, our method does not require well-defined and sensitive organometallic reagents and thus is a user-friendly and operationally simple protocol for assembling phenylacetic acids.
The epimetallation and carbonation of carbonyl and imino derivatives: Epivanadation route to 2-amino and 2-hydroxy acids
Eisch, John J.,Fregene, Paul O.,Gitua, John N.
, p. 4647 - 4653 (2008/03/12)
The feasibility of hydrocarboxylating carbonyl and imino derivatives by the two-step process of epimetallation and carbonation has been demonstrated with the model substrates of 9-fluorenone and 9-fluorenone anil. With lithium vanadium dihydride as the epimetallating agent, such hydrocarboxylation has led to a 75% yield of 9-hydroxy-9-fluorenecarboxylic acid and a 65% yield of 9-(N-phenylamino)-9-fluorenecarboxylic acid, respectively. Some initial success in extending the scope of this reaction to other substrates, such as benzophenone, has been achieved by using other epimetallating agents, like the presumed LiV(CH3)2 and Ti(OPri)2. A brief review of the processes and organic synthetic applications of epimetallation and transfer epimetallation of C-C π-bonds is offered as background.
Simultaneous pH-rate profiles applied to the two step consecutive sequence A→B→C: A theoretical analysis and experimental verification
Andraos, John,Lathioor, Edward C.,Leigh, William J.
, p. 365 - 373 (2007/10/03)
The absorbance extremum method introduced to resolve the rate constant-reaction step ambiguity problem in two step consecutive reactions is applied to cases where the rate constant in each step is pseudo first order and dependent on catalyst concentration. In particular, acid and base catalyzed reactions of substrates in aqueous solution are examined. Resultant simultaneous pH-rate profile functions are treated in the context of the ambiguity problem and a detailed account of the possible interactions between pH-rate profiles is also given. The merits of this method include its general scope, its applicability to reactions for which it may be experimentally difficult to resolve the ambiguity assignment by other means, and its use of rate data acquired from original kinetic traces without requiring additional information. The theoretical analysis is verified and tested experimentally for the hydration of fluorenylideneketene in dilute aqueous perchloric acid solutions.
NITRATION OR CARBOXYLATION CATALYSTS
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, (2008/06/13)
In the presence of an imide compound (e.g., N-hydroxyphthalimide) shown by the following formula (1): ???wherein R1and R2represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group and a cycloalkyl group, and R1and R2may bond together to form a double bond, or an aromatic or non-aromatic ring, and Y is an O or OH, and n denotes 1 to 3;, a substrate is allowed to contact with at least one reactant selected from (i) a nitrogen oxide and (ii) a mixture of carbon monoxide and oxygen to be introduced with at least one functional group selected from a nitro group and a carboxyl group. The nitrogen oxide includes, for example, a compound represented by the formula NxOy(e.g., N2O3, NO2). The substrate includes, for example, a compound having a methine carbon atom (e.g., adamantane), a compound having a methyl group or a methylene group at an adjacent moiety of an aromatic ring. According to such reaction, the substrate can be efficiently nitrated or carboxylated even in a mild or moderate condition.
