- Palladium-Catalyzed Butoxycarbonylation of Polybromo(hetero)arenes: A Practical Method for the Preparation of (Hetero)arenepolycarboxylates and -carboxylic Acids
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The palladium-catalyzed alkoxycarbonylation of polybromo (hetero)arenes was investigated systematically. The results show that cheap and readily available in situ Pd(OAc) 2/ rac -BINAP catalyst can catalyze the butoxycarbonylation of various polybromo(hetero)arenes efficiently, and gave (hetero)arenepolycarboxylates with moderate to high yield (59-94%). Using this method, two new compounds, 4,4'-bis(butoxycarbonyl)-1,1'-bi-2-naphthol and dibutyl [2,2'-bipyrimidine]-5,5'-dicarboxylate, are reported for the first time. In addition, the gram-scale preparation of carboxylate and carboxylic acids was successful performed by butoxycarbonylation followed by hydrolysis. This shows the wide scope of substrates and practical applications of the Pd(OAc) 2/ rac -BINAP catalytic system. Moreover, these carboxylic acids and carboxylates can be used as ligands or structural units to construct MOFs, metal complexes, and COFs etc.
- Ji, Baoming,Jing, Yongkang,Liang, Rong,Lu, Zhiqiang,Wu, Weilong,Yan, Xianghe,Zhang, Deyi
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- Synthesis, spectroscopic characterization and density functional studies of a bis-benzimidazole derivative and of its complexes with palladium(II) halides
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The 2,6-bis(benzimidazol-2′-ylthiomethyl)pyridine (L) ligand and its palladium(II) complexes [Pd(L)X]X (X = Cl, Br, and I) have been synthesized and characterized by spectroscopic data acquisition. The ligand (L) was prepared by conventional heating as well as by microwave irradiation. Microwave irradiation shows additional features, including an easy workup, a much faster reaction and higher yields. The molar conductivity data reveal that the complexes form a 1:1 electrolyte in DMSO. The geometries, ground-state energetics and vibrational spectra of (L) and of its complexes have been elucidated, in terms of quantum chemical calculations. In the mononuclear complexes, the palladium atom is coordinated to three nitrogen atoms and one terminal halogen atom in a slightly distorted square planar arrangement. The present elemental analyses, FT-IR (mid, far), 1H and 13C NMR spectra are in good accordance with the square planar geometry around the Pd ion. The thermal behaviors of the complexes have been assessed by thermal gravimetric and differential thermal analyses.
- Aghatabay, Naz Mohammed,Altun, Ahmet,Gürbüz, Mustafa Ulvi,Türkyilmaz, Murat
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p. 905 - 912
(2014/08/18)
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- Transesterification of various methyl esters under mild conditions catalyzed by tetranuclear zinc cluster
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(Chemical Equation Presented) A new catalytic transesterification promoted by a tetranuclear zinc cluster was developed. The mild reaction conditions enabled the reactions of various functionalized substrates to proceed in good to high yield. A large-scale reaction under solvent-free conditions proceeded with a low E-factor value (0.66), indicating the high environmental and economical advantage of the present catalysis.
- Iwasaki, Takanori,Maegawa, Yusuke,Hayashi, Yukiko,Ohshima, Takashi,Mashima, Kazushi
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p. 5147 - 5150
(2008/09/21)
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- Facile synthesis of polypyridine esters: A route to functionalized aldehydes
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A wide range of ester-substituted oligopyridines, based on pyridine, 1,8-naphthyridine, 1,10-phenanthroline, 2,2'-bipyridine, and 2,2':6',6-terpyridine units, has been synthesized and fully characterized. The principal reaction involves the palladium(0)-catalyzed carboalkoxylation of the bromo-, chloro- or triflate-substituted pyridine unit with carbon monoxide in the presence of a primary alcohol as nucleophile and a tertiary amine as base. Monofunctionalization of disubstituted compounds is realized by reaction in ethanol under mild conditions (70 °C, 1 atm CO). Stepwise reduction of selected esters with sodium borohydride, followed by Swern oxidation, affords the corresponding carbaldehydes in good yield. Several products are reported for the first time. The synthetic methods reported herein represent a valuable approach to the large-scale preparation of ester-functionalized oligopyridines that can be subsequently transformed to the corresponding alcohols or acids. These procedures also provide a practical methodology to the rational design of ligands bearing different kinds of functionalities.
- El-Ghayoury,Ziessel
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p. 7757 - 7763
(2007/10/03)
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- Process for the preparation of 2,6-pyridinedicarboxylic acid esters
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A process for the preparation of 2,6-pyridinedicarboxylic acid esters of the general formula: STR1 wherein R1 is a C1 -C6 -alkyl group, a C3 -C6 -cycloalkyl group, an aryl group or an arylalkyl group, and R2 and R3 independently of one another are hydrogen or chlorine and R4 is hydrogen, a C1 -C6 -alkyl group, a C1 -C6 -alkoxy group or fluorine. The 2,6-pyridinedicarboxylic acid esters are obtained by reaction of the corresponding halopyridines with carbon monoxide and an alcohol of the general formula: wherein R1 has the abovementioned meaning, in the presence of a base and of a complex of palladium with a bis-diphenylphosphine. 2,6-Pyridinedicarboxylic acid esters are intermediates for the preparation of compounds having anti-inflammatory action.
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- The preparation of pyridinecarboxylates from chloropyridines by the palladium-catalyzed alkoxycarbonylation
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The preparation of pyridinecarboxylates and pyridinedicarboxylates by alkoxycarbonylation of chloropyridines with carbon monoxide in the presence of palladium acetate and 1,1'-bis(diphenylphosphino)ferrocene is described. The process uses readily available starting materials and affords pyridinecarboxylates in good to very good yields.
- Bessard, Yves,Crettaz, Roger
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p. 2589 - 2602
(2007/10/03)
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- A convenient synthetic route to polypyridine-esters by palladium- promoted carboalkoxylation
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Pyridine and oligopyridines bearing halide or triflate groups react smoothly with CO (1 atm) and n-butanol in the presence of a tertiary amine and a catalytic amount of bis(triphenylphosphine)palladium dichloride to afford the corresponding esters. When ethanol and a disubstituted substrate are used under milder conditions, selective mono-carboalkoxylation occurs. Amidation is effected using a primary amine as nucleophile.
- El-ghayoury, Abdelkrim,Ziessel, Raymond
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p. 4473 - 4476
(2007/10/03)
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