- Electrocatalytic hydrogenation of benzoic acids in a proton-exchange membrane reactor
-
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
-
supporting information
p. 7363 - 7368
(2021/09/08)
-
- Polysilane-Immobilized Rh-Pt Bimetallic Nanoparticles as Powerful Arene Hydrogenation Catalysts: Synthesis, Reactions under Batch and Flow Conditions and Reaction Mechanism
-
Hydrogenation of arenes is an important reaction not only for hydrogen storage and transport but also for the synthesis of functional molecules such as pharmaceuticals and biologically active compounds. Here, we describe the development of heterogeneous Rh-Pt bimetallic nanoparticle catalysts for the hydrogenation of arenes with inexpensive polysilane as support. The catalysts could be used in both batch and continuous-flow systems with high performance under mild conditions and showed wide substrate generality. In the continuous-flow system, the product could be obtained by simply passing the substrate and 1 atm H2 through a column packed with the catalyst. Remarkably, much higher catalytic performance was observed in the flow system than in the batch system, and extremely strong durability under continuous-flow conditions was demonstrated (>50 days continuous run; turnover number >3.4 × 105). Furthermore, details of the reaction mechanisms and the origin of different kinetics in batch and flow were studied, and the obtained knowledge was applied to develop completely selective arene hydrogenation of compounds containing two aromatic rings toward the synthesis of an active pharmaceutical ingredient.
- Miyamura, Hiroyuki,Suzuki, Aya,Yasukawa, Tomohiro,Kobayashi, Shu
-
supporting information
p. 11325 - 11334
(2018/09/06)
-
- Epimerization of 2- or 4- substituted cyclohexanecarboxylic acids
-
The present invention relates to a new method for obtaining a purity of about 93% to 100% of the trans form of 2- or 4-substituted cyclohexanecarboxylic acid or reactive derivatives thereof from the cis form or a mixture of the cis and trans forms by a single step, particularly, to a method for obtaining a purity of substantially 100% of the trans form of 4-substituted cyclohexanecarboxylic acid.
- -
-
-
- Separation of cis/trans-cyclohexanecarboxylates by enzymatic hydrolysis: Preference for diequatorial isomers
-
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.
-
p. 9029 - 9032
(2007/10/03)
-
- N-(Cyclohexylcarbonyl)-D-phenylalanines and related compounds. A new class of oral hypoglycemic agents. 2
-
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
-
p. 1436 - 1441
(2007/10/02)
-