62984-53-6Relevant articles and documents
(η5-Pentamethylcyclopentadienyl)iridium Complex Catalyzed Imine Reductions Utilizing the Biomimetic 1,4-NAD(P)H Cofactor and N-Benzyl-1,4-dihydronicotinamide as the Hydride-Transfer Agent
Soetens, Mathieu,Drouet, Fleur,Riant, Olivier
, p. 929 - 933 (2017/03/27)
The interaction between synthetic organometallic complexes and metabolic cofactors has proven to be a newly emerging topic in bioorganometallic chemistry. Thus, the first cationic Cp*Ir-catalyzed (Cp=η5-pentamethylcyclopentadienyl) imine reduction in neutral buffered aqueous medium was examined. The reaction was found to proceed through hydride transfer from NADH as the hydride source at room temperature in air. Cationic Cp*Ir complexes proved to be the most efficient catalysts for this transformation. We also highlighted that the choice of the proton source was essential. The method was subsequently applied to cyclic and noncyclic imines. Eventually, the concept was extended to the reductive alkylation of one amine.
Synthesis of trisubstituted ureas by a multistep sequence utilizing recyclable magnetic reagents and scavengers
Kainz, Quirin M.,Zeltner, Martin,Rossier, Michael,Stark, Wendelin J.,Reiser, Oliver
, p. 10038 - 10045 (2013/08/23)
Unprecedented magnetic borohydride exchange (mBER), magnetic Wang aldehyde (mWang) and magnetic amine resins were prepared from highly magnetic polymer-coated cobalt or iron nanoparticles. Microwave irradiation was used to obtain excellent degrees of functionalization (>95 %) and loadings (up to 3.0 mmol g-1) in short reaction times of 15 min or less. A small library of ureas and thioureas was synthesized by the exclusive application of these magnetic resins. As a first step, a reductive amination of aromatic and aliphatic aldehydes was carried out with mBER. The excess of primary amine needed to complete the reaction was subsequently scavenged selectively by mWang. Simple magnetic decantation from the resins resulted in secondary amines in good to excellent yields and purities. The used magnetic resins were efficiently regenerated and reused for the next run. In a second step, the secondary amines were converted to trisubstituted (thio)ureas in excellent yields and purities by stirring with an excess of iso(thio)cyanate, which was scavenged by addition of the magnetic amine resin after completion of the reaction. The whole reaction sequence is carried out without any purification apart from magnetic decantation; moreover, conventional magnetic stirring can be used as opposed to the vortexing required for polystyrene resins. Do it magnetically! A small library of trisubstituted ureas and thioureas was synthesized in high yields and purities by a multistep sequence exclusively applying magnetic reagents and scavengers. No purification steps were necessary apart from magnetic decantation, and the resins were recycled if possible. The novel resins were conveniently and efficiently prepared starting from polymer-coated magnetic Co/C or Fe/C nanobeads by microwave protocols. Copyright
