138-56-7Relevant articles and documents
Near-Ambient-Temperature Dehydrogenative Synthesis of the Amide Bond: Mechanistic Insight and Applications
Kar, Sayan,Xie, Yinjun,Zhou, Quan Quan,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
, p. 7383 - 7393 (2021/06/30)
The current existing methods for the amide bond synthesis via acceptorless dehydrogenative coupling of amines and alcohols all require high reaction temperatures for effective catalysis, typically involving reflux in toluene, limiting their potential practical applications. Herein, we report a system for this reaction that proceeds under mild conditions (reflux in diethyl ether, boiling point 34.6 °C) using ruthenium PNNH complexes. The low-temperature activity stems from the ability of Ru-PNNH complexes to activate alcohol and hemiaminals at near-ambient temperatures through the assistance of the terminal N-H proton. Mechanistic studies reveal the presence of an unexpected aldehyde-bound ruthenium species during the reaction, which is also the catalytic resting state. We further utilize the low-temperature activity to synthesize several simple amide bond-containing commercially available pharmaceutical drugs from the corresponding amines and alcohols via the dehydrogenative coupling method.
Nickel-Catalyzed Phosphine Free Direct N-Alkylation of Amides with Alcohols
Das, Jagadish,Banerjee, Debasis
, p. 3378 - 3384 (2018/03/26)
Herein, we developed an operational simple, practical, and selective Ni-catalyzed synthesis of secondary amides. Application of renewable alcohols, earth-abundant and nonprecious nickel catalyst facilitates the transformations, releasing water as byproduct. The catalytic system is tolerant to a variety of functional groups including nitrile, allylic ether, and alkene and could be extended to the synthesis of bis-amide, antiemetic drug Tigan, and dopamine D2 receptor antagonist Itopride. Preliminary mechanistic studies revealed the participation of a benzylic C-H bond in the rate-determining step.
Efficient fluoride-catalyzed conversion of CO2 to CO at room temperature
Lescot, Camille,Nielsen, Dennis U.,Makarov, Ilya S.,Lindhardt, Anders T.,Daasbjerg, Kim,Skrydstrup, Troels
supporting information, p. 6142 - 6147 (2014/05/20)
A protocol for the efficient and selective reduction of carbon dioxide to carbon monoxide has been developed. Remarkably, this oxygen abstraction step can be performed with only the presence of catalytic cesium fluoride and a stoichiometric amount of a disilane in DMSO at room temperature. Rapid reduction of CO2 to CO could be achieved in only 2 h, which was observed by pressure measurements. To quantify the amount of CO produced, the reduction was coupled to an aminocarbonylation reaction using the two-chamber system, COware. The reduction was not limited to a specific disilane, since (Ph 2MeSi)2 as well as (PhMe2Si)2 and (Me3Si)3SiH exhibited similar reactivity. Moreover, at a slightly elevated temperature, other fluoride salts were able to efficiently catalyze the CO2 to CO reduction. Employing a nonhygroscopic fluoride source, KHF2, omitted the need for an inert atmosphere. Substituting the disilane with silylborane, (pinacolato)BSiMe2Ph, maintained the high activity of the system, whereas the structurally related bis(pinacolato)diboron could not be activated with this fluoride methodology. Furthermore, this chemistry could be adapted to 13C-isotope labeling of six pharmaceutically relevant compounds starting from Ba13CO 3 in a newly developed three-chamber system.
