N,N-Dialkylation of Acyl Hydrazides with Alcohols Catalyzed by Amidato Iridium Complexes via Borrowing Hydrogen

Abstract

Direct N,N-dialkylation of acyl hydrazide catalyzed by a series of amidato iridium complexes bearing an electron-donating group in the ligand using methanol or ethanol as the alkyl reagent under weak base conditions (10 mol % KHCO 3 ) is described. A wide range of acyl hydrazide derivatives are converted to the corresponding N,N-dialkylated products in excellent yields (38 examples, yields of ≤96%). On the basis of the control experiments and nuclear magnetic resonance studies, a plausible mechanism was proposed. The experimental results indicate that ortho electron-donating groups on the phenyl moiety of the picolinamide ligand play a crucial role in catalytic activity.

Interweaved needle‐shaped α‐Ni(OH)2 nanoparticles adorned on graphene oxide: A new class of heterogeneous catalysts for α‐alkylation of ketones and synthesis of azines

“…45 Another possibility is the formation of mono-/di-alkylated-N products. 46 Only a few reports are available on the synthesis of azines from 1 alcohols and hydrazine hydrates. 39,[47][48][49] Therefore, there is a pursuit for the design of cheap, green, and sustainable catalysts for these reactions.…”

Half-sandwich ruthenium complexes with acylhydrazone ligands: synthesis and catalytic activity in the N-alkylation of hydrazides

“…22 Other types of catalysts were also reported in succession, but these catalysts typically required a high catalytic temperature and long catalytic time, which are not conducive to large-scale industrial use (Scheme 2a). 23 Based on the stability, and high and diverse catalytic activities of half-sandwich transition metal complexes, which have been widely employed in many organic conversions under mild conditions, such as the oxidation coupling of amines, catalytic hydrogenation of carbonyl substrates, and cyanosilylation of aldehydes and nitrile hydration. 23 Herein, we report a new type of half-sandwich ruthenium complex catalyst with an arylhydrazone ligand, which exhibited high catalytic efficiency for the N-alkylation of acyl hydrazides using alcohols as a coupling partner.…”

“…23 Based on the stability, and high and diverse catalytic activities of half-sandwich transition metal complexes, which have been widely employed in many organic conversions under mild conditions, such as the oxidation coupling of amines, catalytic hydrogenation of carbonyl substrates, and cyanosilylation of aldehydes and nitrile hydration. 23 Herein, we report a new type of half-sandwich ruthenium complex catalyst with an arylhydrazone ligand, which exhibited high catalytic efficiency for the N-alkylation of acyl hydrazides using alcohols as a coupling partner. A variety of N-alkylated hydrazides were prepared in good yields under mild conditions.…”

“…22 Other types of catalysts were also reported in succession, but these catalysts typically required a high catalytic temperature and long catalytic time, which are not conducive to large-scale industrial use (Scheme 2a). 23…”

Synthesis and catalytic activity of half‐sandwich iridium complexes with acylhydrazone ligands for N‐alkylation of hydrazides under mild conditions

“…Subsequently, different categories of catalysts have been reported, but they necessitate high temperatures and extended reaction time, which are not suitable for industrial-scale applications (Scheme 2a). 23 Iridium metal has found widespread applications in the field of synthetic catalysts because of its exceptional chemical properties, abundant resources, superior catalytic activity, and tunability. 18,24 The pyrrolyl hydrazine ligand, characterized by its rigid molecular structure and multiple coordination sites, forms a strong coordination interaction with iridium ions, significantly enhancing the stability of the resulting complex.…”