Benzimidazol-2-ylidene ruthenium complexes for C-N bond formation through alcohol dehydrogenation

TURKISH JOURNAL OF CHEMISTRY, Год журнала: 2023, Номер 47(5), С. 1209 - 1223

Опубликована: Окт. 31, 2023

A low temperature hydrogen borrowing approach to generate secondary amines using benzimidazole-based N-heterocyclic carbene (BNHC) ruthenium complexes is reported. series of the piano-stool type [(η6 -p-cymene)(BNHC)RuCl2 ] (1a-g) were synthesized via one-pot reaction NHC salt precursor, Ag2 O, and [RuCl2 (p-cymene)]2 characterized conventional spectroscopic techniques. The geometry two precursors, -p-cymene)(Me4BnMe2 BNHCCH2OxMe)RuCl2 (1f) -p-cymene)(Me5BnMe2 (1g), was studied by single crystal X-ray diffraction. These catalysts found dehydrogenate alcohols efficiently at temperatures as 50 °C allow Schiff-base condensation subsequent imine hydrogenation afford amines. Notably, this ruthenium-based procedure enables N-alkylation aromatic heteroaromatic primary with a wide range in excellent yields up 98%. present methodology green water liberated sole byproduct.

Язык: Английский

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Nickel complexes bearing quinoline derived NNS donor ligands as catalytic activators for N‐alkylation of anilines with alcohols

Chemistry - An Asian Journal, Год журнала: 2024, Номер unknown

Опубликована: Июль 12, 2024

Abstract Herein, we have reported a new series of NNS‐donor ligands coordinated Ni(II) complexes and utilized them as catalytic activator to synthesize N ‐alkylated amines 1,2‐disubstituted benzimidazoles. The reaction thiophenol/4‐chlorothiophenol/4‐methylthiophenol/4‐methoxythiophenol with 2‐bromo‐ ‐quinolin‐8‐yl‐acetamide in presence sodium hydroxide ethanol at 80 °C gave [C 9 H 6 N‐NH−C(O)−CH 2 ‐S−Ar] [Ar=C 5 ( L1 ); C 4 Cl‐4 (L2 Me‐4 (L3 ) ‐OMe‐4 (L4 )], respectively. corresponding ‐ L4 Ni(OAc) methanol for 3 hours resulted octahedral nickel [( ‐H) Ni] C1 ), L2 C2 L3 C3 C4 All compounds been characterized by micro spectroscopic analysis. molecular structure – has also determined single crystal X‐ray diffraction data. utility were evaluated the ‐alkylation aniline benzyl alcohols, benzimidazoles synthesis. obtained results indicate that complex showed better activity both alcohols [catalyst loading: 2.0 mol %; Yield up 92 %], derivatives 94 %)]. mechanistic studies suggested works through hydrogen borrowing from alcohol its subsequent utilization situ reduction imine. experimentally observed reactivity patterns found good agreement HOMO‐LUMO energy gaps DFT analysis complexes.

Язык: Английский

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Unsymmetrical pyrenyl‐thiophene‐benzothiazole iridium complexes supported on reduced graphene oxide as an efficient catalyst for N‐alkylation of amides with alcohols

ChemistrySelect, Год журнала: 2023, Номер 8(45)

Опубликована: Дек. 1, 2023

Abstract An iridium complex based on the unsymmetrical pyrenyl‐thiophene‐benzothiazole ligand was synthesized, and supported reduced graphene oxide successfully. The developed catalyst PTB‐Ir@rGO characterized through SEM, TEM, XPS, EDS. Meanwhile, we found that this heterogeneous had high catalytic activity in N‐alkylation of benzamide with alcohols via borrowing hydrogen strategy. Moreover, several control reactions preliminary mechanism explorations were carried out to study transformation. Finally, recycling experiment showed could be reused at least five times without a significant decrease activity.

Язык: Английский

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