107175-80-4Relevant articles and documents
Cycloamidination of Aminoalkenes with Nitriles: Synthesis of Substituted 2-Imidazolines and Tetrahydropyrimidines
Huang, Shujian,Shao, Yinlin,Zhang, Lixin,Zhou, Xigeng
, p. 14452 - 14456 (2015)
The first catalytic cycloamidination of aminoalkenes with nitriles has been achieved by using rare-earth complexes. This reaction is equivalent to the desired intramolecular hydroamination of alkenylamidines, and allows a new direct access to substituted 2-imidazolines and tetrahydropyrimidines in high yields under operationally simple reaction conditions. Moreover, the methodology is also efficient for synthesis of symmetric and unsymmetric bridged diimidazolines. Compared with the traditional stepwise-mediated synthetic approaches, the present method avoids the use of additives and harsh reaction conditions, and thus leads to a completely different product distribution. Mechanistic data suggest that the reaction involves the initial NH activation by lanthanide complex followed by nitrile insertion into a Ln-N bond to form an amidinate lanthanide intermediate which undergoes the cyclization.
A proton-responsive annulated mesoionic carbene (MIC) scaffold on IR complex for proton/hydride shuttle: An experimental and computational investigation on reductive amination of aldehyde
Bera, Jitendra K.,Daw, Prosenjit,Din Reshi, Noor U.,Ehmann, Kira R.,H?lscher, Markus,Leitner, Walter,Pandey, Pragati
, p. 3849 - 3863 (2020/11/23)
A Cp*Ir(III) complex (1) bearing a proton-responsive hydroxy unit on an annulated imidazo[1,2-a][1,8]naphthyridine based mesoionic carbene scaffold was synthesized by two different synthetic routes. The molecular structure of 1 revealed an anionic lactam form of the ligand. The acid?base equilibrium between the lactam-lactim tautomers on the ligand scaffold was examined by 1H NMR and UV?vis spectra. The pKa of the appendage ?OH group in the lactim form of 1 was estimated to assess the proton transfer property of the catalyst. The catalytic efficacy of 1 for reductive amination of aldehyde was evaluated by utilizing three different hydrogen sources: molecular H2iPrOH/KOtBu combination, and HCOOH/Et3N (5:2) azeotropic mixture. The HCOOH/Et3N (5:2) azeotropic mixture rotocol was found to be the best amon the three different h dro enation methods. Catalyst 1 hydrogenates imines chemoselectively over carbonyls under the reaction conditions. A range of aldehydes was reductively aminated to the corresponding secondary amines using the HCOOH/Et3N (5:2) azeotropic mixture. Further, catalyst 1 showed high efficiency for the reduction of a wide variety of N-heterocyclic imine derivatives. The lactam-lactim tautomerization of the ligand system is proposed for direct hydrogenation, whereas only the lactam form operates in the strongly basic medium (iPrOH/KOtBu). Under HCOOH/Et3N (5:2) conditions, the lactam scaffold is not protonated; rather, an outer-sphere hydride transfer from formate to the Ir is proposed, which is supported by 1H NMR and DFT calculations. Finally, ligand-promoted hydride transfer from metal-hydride to the protonated imine affords the corresponding amine. A close agreement between the experimentally estimated and computed thermodynamic/kinetic parameters gives credence to the metal-ligand cooperative mechanism for the imine hydrogenation reaction using the HCOOH/Et3N (5:2) azeotropic mixture.
Synthesis of N?H Bearing Imidazolidinones and Dihydroimidazolones Using Aza-Heck Cyclizations
Xu, Feiyang,Shuler, Scott A.,Watson, Donald A.
supporting information, p. 12081 - 12085 (2018/09/11)
The synthesis of unsaturated, unprotected imidazolidinones via an aza-Heck reaction is described. This palladium-catalyzed process allows for the cyclization of N-phenoxy ureas onto pendant alkenes. The reaction has broad functional group tolerance, can b
