77314-38-6Relevant articles and documents
Heterogenizing a Homogeneous Nickel Catalyst Using Nanoconfined Strategy for Selective Synthesis of Mono- And 1,2-Disubstituted Benzimidazoles
Shadab,Dey, Gargi,Sk, Motahar,Banerjee, Debasis,Aijaz, Arshad
supporting information, p. 16042 - 16047 (2021/11/04)
A homogeneous Ni-phenanthroline catalyst was successfully immobilized into the cavities of a metal-organic framework, ZIF-8. The as-synthesized heterogeneous catalyst, Ni-Phen@ZIF, represents the first MOF based catalyst that enables dehydrogenative coupling of alcohols with aromatic diamines for selective synthesis of both mono- and 1,2-disubstituted benzimidazoles. The catalyst survived under harsh basic conditions, characterized by SEM, TEM, BET, PXRD, and EDX elemental mappings. The presence of the nanoconfined Ni-phenanthroline complex and the formation of extra Lewis acid sites during catalysis in the Ni-Phen@ZIF structure, confirmed by TPD analysis and kinetic experiments, might be responsible for higher activity and selectivity.
Tunable Triazole-Phosphine-Copper Catalysts for the Synthesis of 2-Aryl-1H-benzo[d]imidazoles from Benzyl Alcohols and Diamines by Acceptorless Dehydrogenation and Borrowing Hydrogen Reactions
Xu, Zhaojun,Wang, Duo-Sheng,Yu, Xiaoli,Yang, Yongchun,Wang, Dawei
supporting information, p. 3332 - 3340 (2017/10/06)
Triazole-phosphine-copper complexes (TAP?Cu) have been synthesized and applied as tunable and efficient catalysts for the selective synthesis of fluoro-substituted 2-aryl-1H-benzo[d]imidazole and 1-benzyl-2-aryl-1H-benzo[d]imidazole derivatives from simple alcohols in only one step. TAP?Cu exhibited excellent and tunable catalytic activity for both dehydrogenation and borrowing hydrogen reactions with more than 80 examples being demonstrated for the first time. It was observed that the ligand played a critical role in catalyst activity. Mechanistic studies and deuterium labeling experiments indicated that the reactions proceeded by an initial and reversible alcohol dehydrogenation resulting in a copper hydride intermediate. This was also supported by the direct observation of a diagnostic copper hydride signal by solid-state infrared spectroscopy. The TAP?Cu-H complex showed absorptions at 912 cm?1 that could be assigned to copper?hydride stretches. Furthermore, the direct trapping of an intermediate bisimine was also successfully performed. (Figure presented.).
Pyrolysis of N1,N3-Disubstituted 5-Methyl- and 5-Chlorobenzimidazolines
Chalapathi Rao, C. V.,Kondal Reddy, K.,Rao, N. V. Subba
, p. 967 - 969 (2007/10/02)
The pyrolysis of 2-aryl-1-benzyl-3,5-dimethyl(I)-, 5-chloro-3-methyl(II)-, 3-substituted-benzyl-5-methyl(III)- and 3-substituted-benzyl-5-chloro-(IV)-benzimidazolines has been carried out to study the orientation of their elimination reactions.The benzyl group is eliminated in preference to methyl in benzimidazolines of the types (I) and (II) irrespective of the nature of the substituent in phenylene and aryl moieties.The course of the elimination reaction in compounds of the types (III) and (IV) appears to be determined by the relative stabilities of benzyl and substituted benzyl radicals.The structures of the pyrolysis products have been established on the basis of spectral and chemical evidences.
