- Silver/manganese dioxide nanorod catalyzed hydrogen-borrowing reactions and tert-butyl ester synthesis
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Silver/manganese dioxide (Ag@MnO2) nanorods are synthesized and characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy. It was discovered that Ag@MnO2 nanorods can realize hydrogen-borrowing reactions in high yields and are also effective for the synthesis of tert-butyl esters from aryl cyanides and tert-butyl hydroperoxide in a short period of time. Mechanistic experiments revealed that this catalytic system acts as a Lewis acid in hydrogen-borrowing reactions, while the synthesis of tert-butyl esters occurs through a radical pathway. This is the first report on the excellent catalytic activity of Ag@MnO2 nanorods as a catalyst.
- Luo, Huanhuan,Wang, Dawei,Xu, Zhaojun,Yang, Bobin,Yang, Yike
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p. 708 - 715
(2021/03/03)
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- A Zirconium Indazole Carboxylate Coordination Polymer as an Efficient Catalyst for Dehydrogenation-Cyclization and Oxidative Coupling Reactions
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Rational ligand design is crucial for achieving widespread applications of coordination polymers. The preparation, structural characterisation, and catalytic applications of zirconium (IV) coordination polymer (Zr-IDA), which was derived from 1-(carboxymethyl)-1H-indazole-5-carboxylic acid are reported. The Zr-IDA catalyst contains porous and highly crystalline particles with a quasi-spherical morphology around 100 nm in size, and Zr was coordinated with both O and N as shown by FT-IR and XPS measurements. Importantly, the Zr-IDA catalyst shows great activity, selectivity and stability in the oxidative coupling of benzyl cyanides with tert-butyl hydroperoxide to afford tert-butyl peresters, and the dehydrogenation cyclization of o-phenylenediamines with aromatic alcohols to afford 1,2-disubstituted benzimidazole derivatives. Mechanistic investigations were carried out to study these reactions and the developed catalytic system in more detail.
- Sang, Xinxin,Hu, Xinyu,Tao, Rong,Zhang, Yilin,Zhu, Haiyan,Wang, Dawei
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p. 123 - 129
(2020/02/21)
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- Highly Active Manganese-Mediated Acylation of Alcohols with Acid Chlorides or Anhydrides
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To explore further the practical uses of highly active manganese (Mn?), a variety of alcohols were treated with Mn?, and the resulting complexes were coupled with acid chlorides and/or acetic anhydride in the absence of any extra catalyst. The subsequent reactions took place smoothly under mild conditions, providing the corresponding O-acylation products in good to excellent isolated yields.
- Joo, Seong-Ryu,Youn, Young-Jin,Hwang, Young-Ran,Kim, Seung-Hoi
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p. 2665 - 2669
(2017/10/07)
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- The application of N,N′dibromo-N,N′-1,2-ethanediyl bis(P-toluenesulfonamide) as a powerful reagent for conversion of carboxylic acids into esters and amides with triphenylphosphine
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In the presence of equivalent amounts of triphenylphenylphosphine and N,N′-dibromo-N,N′-1,2-ethanediylbis(p-toluenesulphonamide) ester and amide compounds can be generated in high yields from the corresponding carboxylic acid and alcohols or amines.
- Khazaei, Ardeshir,Mallakpour, Shadpour,Zolfigol, Mohammad Ali,Ghorbani-Vaghei, Ramin,Kolvari, Eskandar
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p. 1715 - 1721
(2007/10/03)
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- Convenient preparations of t-butyl esters and ethers from t-butanol
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A one-pot preparation of t-butyl esters and ethers is described that proceeds from the carboxylic acid or alcohol and t-butanol using only anhydrous magnesium sulfate and catalytic sulfuric acid as additional reagents. The method affords t-butyl esters and ethers in good yields and is applicable to a variety of substrates.
- Wright, Stephen W.,Hageman, David L.,Wright, Ann S.,McClure, Lester D.
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p. 7345 - 7348
(2007/10/03)
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- ANOMALOUS ORIENTATION EFFECTS DURING BENZOYLOXYLATIONS BY "SILVER BROMIDE DIBENZOATE"
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The solid complex formed from bromine and silver benzoate reacts with both arenes and alkenes to form aryl and alkyl benzoates, respectively.Highly unusual substituent effects are observed in the benzoyloxylations of arenes.Electron-withdrawing groups (e.g. -NO2, -CN,-CO-) on the aromatic ring facilitate reaction though directing the attacking reagent exclusively to the meta position.In alkanes, tertiary positions are most prone to attack.
- Bryce-Smith, Derek,Isaacs, Neil S.,Tumi, Seddeg O.
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p. 1471 - 1472
(2007/10/02)
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- ACTIVATION OF REDUCING AGENTS. SODIUM HYDRIDE CONTAINING COMPLEX REDUCING AGENTS. XIV. NaCoCO4 AS AN SRN1 NUCLEOPHILE IN THE CARBONYLATION OF ARYL HALIDES BY CoCRACO AT ATMOSPHERIC PRESSURE. NEW PREPARATION OF NaCoCO4 BY NaH REDUCTION OF DICOBALT OCTACARBONYL
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The only detectable cobalt carbonyl species present in CoCRACO (NaH/t-AmONa/Co(OAc)2/CO) (t-Am = tert-amyl) is NaCoCO4.The simultaneous presence of NaH, t-AmONa, NaCoCO4 and some soluble, non-carbonyl, cobalt species allows highly catalytic carbonylation of C6H5Br under very mild conditions, while NaCoCO4 alone can carbonylate C6H5Br under irradiation (350 nm).In the presence of t-AmONa, the reaction is highly catalytic with respect to cobalt.These results strongly suggest a SRN1 mechanism.It is suggested that catalytic carbonylations with CoCRACO take place by a SRN1, electron-initiated, reaction.A new, very convenient method of preparation of NaCoCO4 by quantitative reduction of Co2CO8 with NaH is also described.
- Brunet, Jean-Jacques,Sidot, Christian,Caubere, Paul
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p. 229 - 241
(2007/10/02)
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