4169-04-4Relevant academic research and scientific papers
Development of effective bidentate diphosphine ligands of ruthenium catalysts toward practical hydrogenation of carboxylic acids
Saito, Susumu,Wen, Ke,Yoshioka, Shota
, p. 1510 - 1524 (2021/06/18)
Hydrogenation of carboxylic acids (CAs) to alcohols represents one of the most ideal reduction methods for utilizing abundant CAs as alternative carbon and energy sources. However, systematic studies on the effects of metal-to-ligand relationships on the catalytic activity of metal complex catalysts are scarce. We previously demonstrated a rational methodology for CA hydrogenation, in which CA-derived cationic metal carboxylate [(PP)M(OCOR)]+ (M = Ru and Re; P = one P coordination) served as the catalyst prototype for CA self-induced CA hydrogenation. Herein, we report systematic trial- and-error studies on how we could achieve higher catalytic activity by modifying the structure of bidentate diphosphine (PP) ligands of molecular Ru catalysts. Carbon chains connecting two P atoms as well as Ar groups substituted on the P atoms of PP ligands were intensively varied, and the induction of active Ru catalysts from precatalyst Ru(acac)3 was surveyed extensively. As a result, the activity and durability of the (PP)Ru catalyst substantially increased compared to those of other molecular Ru catalyst systems, including our original Ru catalysts. The results validate our approach for improving the catalyst performance, which would benefit further advancement of CA self-induced CA hydrogenation.
TiO2-Supported Re as a General and Chemoselective Heterogeneous Catalyst for Hydrogenation of Carboxylic Acids to Alcohols
Toyao, Takashi,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Morita, Yoshitsugu,Kamachi, Takashi,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
, p. 1001 - 1006 (2017/02/05)
TiO2-supported Re, Re/TiO2, was found to promote selective hydrogenation of carboxylic acids having aromatic and aliphatic moieties to the corresponding alcohols. Re/TiO2showed superior results compared to other transition-metal-loaded TiO2and supported Re catalysts for selective hydrogenation of 3-phenylpropionic acid. 3-phenylpropanol was produced in 97 % yield under mild conditions (5 MPa H2at 140 °C). Contrary to typical heterogeneous catalysts, Re/TiO2does not lead to the formation of dearomatized byproducts. The catalyst is recyclable and shows a wide substrate scope in the synthesis of alcohols (22 examples; up to 97 % isolated yield).
Highly Enantioselective Hydrogenation of Amides via Dynamic Kinetic Resolution Under Low Pressure and Room Temperature
Rasu, Loorthuraja,John, Jeremy M.,Stephenson, Elanna,Endean, Riley,Kalapugama, Suneth,Clément, Roxanne,Bergens, Steven H.
, p. 3065 - 3071 (2017/03/11)
High-throughput screening and lab-scale optimization were combined to develop the catalytic system trans-RuCl2((S,S)-skewphos)((R,R)-dpen), 2-PrONa, and 2-PrOH. This system hydrogenates functionalized α-phenoxy and related amides at room temperature under 4 atm H2 pressure to give chiral alcohols with up to 99% yield and in greater than 99% enantiomeric excess via dynamic kinetic resolution.
CATALYSTS AND PROCESSES FOR THE HYDROGENATION OF AMIDES
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Paragraph 0280; 0281, (2014/06/24)
There is provided a process for the reduction of one or more amide moieties in a compound comprising contacting the compound with hydrogen gas and a transition metal catalyst in the presence or absence of a base under conditions for the reduction an amide bond. The presently described processes can be performed at low catalyst loading using relatively mild temperature and pressures, and optionally, in the presence or absence of a base or high catalyst loadings using low temperatures and pressures and high loadings of base to effect dynamic kinetic resolution of achiral amides.
An efficient catalyst for ring opening of epoxides with phenol and thiophenol under solvent-free conditions
Lu, Hong-Fei,Zhou, Jun-Tao,Cheng, He-Long,Sun, Lei-Lei,Yang, Fei-Fei,Wu, Run-Ze,Gao, Yu-Hua,Luo, Zhi-Bin
, p. 11174 - 11184 (2014/01/06)
An efficient and rapid procedure for ring opening reaction of various epoxides with phenol and thiophenol derivatives was developed. The procedure can be obtained at room temperature under solvent-free condition in presence of (C4H12N2)2[BiCl6] Cl·H2O (1 mol %). This catalyst can be reused several times without significant loss of activity.
Straightforward heterogeneous palladium catalyzed synthesis of aryl ethers and aryl amines via a solvent free aerobic and non-aerobic dehydrogenative arylation
Sutter, Marc,Sotto, Nicolas,Raoul, Yann,Metay, Estelle,Lemaire, Marc
supporting information, p. 347 - 352 (2013/03/28)
Aryl ethers have been prepared from cyclohexanone derivatives and various alcohols in the presence of a catalytic amount of palladium on charcoal. The formation of an enol ether followed by an aerobic or non-aerobic dehydrogenation reaction, seem to be the key steps of this transformation. In addition, this new method was also adapted for the synthesis of arylamines.
Heterogeneous palladium-catalyzed synthesis of aromatic ethers by solvent-free dehydrogenative aromatization: Mechanism, scope, and limitations under aerobic and non-aerobic conditions
Sutter, Marc,Lafon, Romain,Raoul, Yann,Metay, Estelle,Lemaire, Marc
supporting information, p. 5902 - 5916 (2013/09/23)
Starting from cyclohexanone derivatives and alcohols, both non-aromatic precursors, aryl ethers could be synthesized in good yields and with good selectivities in the presence of a catalytic amount of Pd/C, in one step, without added solvent, in a reaction vessel open to air. For less reactive substrates, the addition of 1-octene in a closed system under non-aerobic conditions improved the conversion. In addition, the catalyst could be recycled several times with no decrease in the yield of the aryl ether. The process was also used with tetralone derivatives and polyols. Several reactions were performed to propose a mechanism for this transformation. The formation of an enol ether followed by a dehydrogenation reaction seem to be the key steps of this reaction. Aryl ethers were prepared in good yields and with good selectivities in a solvent-free and heterogeneous catalytic dehydrogenative alkylation of cyclohexanones with various alcohols. Three different complementary routes were used, and for the first time, non-aerobic, safe conditions could be used. Moreover, the catalyst could be recycled several times with no decrease in the yield of the aryl ether. Copyright
One-pot synthesis of aryloxypropanediols from glycerol: Towards valuable chemicals from renewable sources
Truscello, Ada M.,Gambarotti, Cristian,Lauria, Mirvana,Auricchio, Sergio,Leonardi, Gabriella,Shisodia, Suresh U.,Citterio, Attilio
supporting information, p. 625 - 628 (2013/03/29)
Glycerol offers an easy and green route for the synthesis of aryloxypropanediols of known pharmacological activity. Glycerol is selectively converted to aryloxypropanediols in a one-pot reaction, through in situ formed glycerol carbonate, under benign and solvent-free conditions. Catalyst and unreacted reagent can be recycled.
α-Aroyloxyaldehydes: Scope and limitations as alternatives to α-haloaldehydes for NHC-catalysed redox transformations
Ling, Kenneth B.,Smith, Andrew D.
experimental part, p. 373 - 375 (2011/02/24)
α-Aroyloxyaldehydes are readily prepared bench stable synthetic intermediates. Their ability to act as α-haloaldehyde surrogates for NHC-promoted redox esterifications and in [4+2] cycloadditions is described.
Design, synthesis, and pharmacological effects of structurally simple ligands for MT1 and MT2 melatonin receptors
Carocci, Alessia,Catalano, Alessia,Lovece, Angelo,Lentini, Giovanni,Duranti, Andrea,Lucini, Valeria,Pannacci, Marilou,Scaglione, Francesco,Franchini, Carlo
experimental part, p. 6496 - 6511 (2010/10/02)
A series of phenoxyalkyl and phenylthioalkyl amides were prepared as melatoninergic ligands. Modulation of affinity of the newly synthesized compound by applying SARs around the terminal amide moiety, the alkyl chain, and the methoxy group on the aromatic ring provides compounds with nanomolar affinity for both melatonin receptor subtypes. Affinity towards MT1 and MT2 receptors were modulated also exploiting chirality. The investigation of intrinsic activity revealed that all the tested compounds behave as full or partial agonists.
