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Upstream product

• 1008-89-5 2-phenylpyridine 
• 1571-08-0 methyl 4-formylbenzoate 
• 619-42-1 4-methoxycarbonylphenyl bromide 
• 34040-64-7 p-methyloxycarbonylbenzyl chloride 
• 1126-46-1 Methyl 4-chlorobenzoate 

Relevant academic research and scientific papers

Ruthenium-Catalyzed C-H Bond Activation/Arylation Accelerated by Biomass-Derived Ligands

A variety of ligands are being explored extensively to achieve enhanced performance for ligand assisted C-H bond activation/functionalization reactions. We explored here several readily available biomass-derived ligands as effective additives to significantly enhance the catalytic activity of arene-Ru(II) dimer for ortho C-H bond arylation in a water-based catalytic reaction. We achieved almost 7-fold enhancement in the catalytic activity with [(η6-p-cymene)RuCl2]2 catalyst in the presence of levulinic acid ligand at 80 °C. Mass investigations revealed the in-situ formation of a ruthenium-levulinate complex, which presumably plays a crucial role in the formation of the important cycloruthenated intermediate by facilitating the initial activation of ortho C-H bond of 2-phenylpyridine. Density functional theoretical studies also inferred that the ligand assisted route is energetically more favorable, where the acetyl group is found to be involved in the deprotonation step.

Ligand-Tuned C–H Bond Activation/Arylation of 2-Arylpyridines over Pyridine-Based N,O/N,N Ligated Ruthenium–Arene Complexes

Water-soluble ruthenium(II)–arene complexes [(η6-arene)Ru(κ2-L)]n+ (n = 0, 1) ([Ru]-1–[Ru]-10) containing pyridine-based bischelating N,O/N,N donor ligands (L1–L5) are synthesized and employed for the catalytic C–H bond activation/arylation of a wide range of 2-phenylpyridines and aryl halides in water, affording the corresponding mono- and biarylated products. Exploring the reactivity of the synthesized complexes, our investigations, including time-dependent 1H NMR spectroscopic studies with ruthenium–arene catalysts, demonstrate a remarkable structure–activity relationship for the ligand-tuned C–H activation/arylation of 2-phenylpyridine, where the complexes with bischelating N,O donor-based ligands (acteylpyridine and picolinate) outperform those with N,N donor ligands (iminopyridine). Moreover, among the N,O donor ligands, a distinct effect of the nature of the coordinating oxygen donor on the catalytic activity is also observed, where ruthenium–arene complexes having N,O donor ligands (acetylpyridine) with neutral oxygen-donor atoms exhibit enhanced catalytic activity over those with anionic oxygen-donor atoms (picolinate). The observed trend in the catalytic activity is attributed to the ligand-promoted facile deprotonation and coordination–decoordination interconversion behavior. In addition, molecular structures for a few of the representative complexes ([Ru]-2, [Ru]-4, and [Ru]-5) are authenticated by single-crystal X-ray diffraction studies.

C?H Bond Activation/Arylation Catalyzed by Arene–Ruthenium–Aniline Complexes in Water

Water-soluble arene–ruthenium complexes coordinated with readily available aniline-based ligands were successfully employed as highly active catalysts in the C?H bond activation and arylation of 2-phenylpyridine with aryl halides in water. A variety of (hetero)aryl halides were also used for the ortho-C?H bond arylation of 2-phenylpyridine to afford the corresponding ortho- monoarylated products as major products in moderate to good yields. Our investigations, including time-scaled NMR spectroscopy and mass spectrometry studies, evidenced that the coordinating aniline-based ligands, having varying electronic and steric properties, had a significant influence on the catalytic activity of the resulting arene–ruthenium–aniline-based complexes. Moreover, mass spectrometry identification of the cycloruthenated species, {(η6-arene)Ru(κ2-C,N-phenylpyridine)}+, and several ligand-coordinated cycloruthenated species, such as [(η6-arene)Ru(4-methylaniline)(κ2-C,N-phenylpyridine)]+, found during the reaction of 2-phenylpyridine with the arene–ruthenium–aniline complexes further authenticated the crucial roles of these species in the observed highly active and tuned catalyst. At last, the structures of a few of the active catalysts were also confirmed by single-crystal X-ray diffraction studies.

Efficient catalytic system for Ru-catalyzed C-H arylation and application to a practical synthesis of a pharmaceutical

A series of K salts of sulfonic acids have been tested as a cocatalyst for Ru-catalyzed C-H arylation. Among them, K 2, 4, 6-trimethylbenzenesulfonate (TMBSK) was found to be most active, and generality of the reaction was confirmed for a variety of nitrogen-containing heterocycles to give corresponding functionalized biaryls in high yields. The present methodology was applied to a practical synthesis of Candesartan Cilexetil.

Rhodium-catalyzed oxidative C-H arylation of 2-arylpyridine derivatives via decarbonylation of aromatic aldehydes

A new concept for aryl-aryl coupling that involves oxidative decarbonylative coupling of aryl C-H bonds and readily available aldehydes has been developed, achieving the aryl-aryl union with complete control of reaction sites.