• Title, Summary, Keyword: carbonylation

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Catalytic Activity of Supported Rhodium(I) Complex for the Carbonylation of Nitrobenzene: Mechanism for Carbamate Formation

  • Kim, Jin-Hyung;Kim, Dae-Won;Cheong, Min-Serk;Kim, Hoon-Sik;Mukherjee, Deb Kumar
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1621-1627
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    • 2010
  • The investigation of the catalytic activity of supported rhodium(I) complex [Rh(P-S)$(CO)_2$] (P-S; polymer anchored salicylic acid) toward the reductive carbonylation of nitrobenzene in DMF medium has been reported. Use of basic cocatalysts in the reaction medium enhanced the percentage of more useful phenyl carbamates. Spectroscopic studies indicate that the reaction proceeds through a dimer species [Rh(HS)(CO)(C(O)$OCH_3$)(${\mu}-OCH_3)]_2$ and phenyl isocyanate is formed as an intermediate. A plausible reaction mechanism based on the identification of reactive intermediates from the soluble rhodium variety has been proposed for the carbonylation process.

Carbonylation of 1-Bromo-2,6-bis(bromomethyl)benzene Catalyzed by Cobalt Carbonyl

  • Sang Chul Shim;Shin Ae Chae;Dong Yeob Lee;Young Zoo Youn;Jae Goo Shim;Chil Hoon Doh
    • Bulletin of the Korean Chemical Society
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    • v.14 no.4
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    • pp.481-485
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    • 1993
  • Dialkyl 1-bromobenzene-2,6-diacetates were easily prepared by the carbonylation of the moiety of benzylic bromide in 1-bromo-2,6-bis(bromomethyl)benzene with alcohol in the presence of NaOAc< TEX>${\cdot}$3H$_2$O and a catalytic amount of Co$_2$(CO)$_8$under the atmospheric pressure of carbon monoxide at room temperature in excellent yield. Alkyl 2,6-bis(alkoxymethyl)benzoates were obtained by the carbonylation of the moiety of aryl bromide in 1-bromo-2,6-bis(alkoxymethyl)-benzene, which derived from 1-bromo-2,6-bis(bromomethyl)benzene, alcohol, NaOR, and CH$_3$I under the same conditions. Alkyl 2,6-bis(carboxymethyl)benzoate was also obtained in a trace amount for 24 hrs at room temperature.

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Carbonylation of Bromo(Bromomethyl)Benzenes to Alkyl Carboalkoxyphenylacetates Catalyzed by Cobalt Carbonyl

  • Shim, Sang-Chul;Doh, Chil-Hoon;Lee, Dong-Yub;Youn, Young-Zoo;Lee, Seung-Yub;Chae, Shin-Ae;Oh, Dae-Hee;Oh, Hun-Seung
    • Bulletin of the Korean Chemical Society
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    • v.13 no.1
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    • pp.45-48
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    • 1992
  • A synthetic method for bis-carbonylation of bromo(bromomethyl)benzenes was described. Alkyl carboalkoxyphenylacetates were easily prepared by the carbonylation of benzylic and arylic bromide moieties in bromo(bromomethyl)benzenes with alcohols in the presence of $K_2CO_3,\;CH_3I$, and a catalytic amount of cobalt carbonyl under the atmospheric pressure of carbon monoxide at room temperature in good to excellent yields. The base played a decisive role in the selectivity of product and $K_2CO_3$ was the best one among bases used.

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Carbonylation of Benzyl Alcohols and Benzyl Bromide to Phenylacetic Acids with Rhodium(Ⅰ) and Iridium(Ⅰ) Complexes

  • Chin Chong Shik;Jung Ho Jin;Hong Seung-gweon
    • Bulletin of the Korean Chemical Society
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    • v.13 no.4
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    • pp.391-395
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    • 1992
  • Rhodium(I) and iridium(II) complexes, M(Cl$O_4$)(CO)$(PPh_3)_2$ and [M(CO)$(PPh_3)_3$]Cl$O_4$ (M = Rh, Ir), and RhX(CO)$(PPh_3)_2$ (X = Cl, Br, OH) catalyze the carbonylation of benzyl alcohols to produce phenylacetic acids under 6 atm of CO at $110^{\circ}C$ in deuterated chloroform. Benzyl alcohols initially undergo dehydration to give dibenzyl ethers which are then carbonylated to benzyl phenylacetates, and the hydrolysis of benzyl phenylacetate produces phenylacetic acids and benzyl alcohols. The carbonylation is accompanied with dehydrogenation followed by hydrogenolysis of benzyl alcohols giving benzaldehydes and methylbenzenes which are also produced by CO2 elimination of phenylacetic acids. Phenylacetic acid is also produced in the reactions of benzyl bromide with CO catalytically in the presence of Rh(Cl$O_4$)(CO)$(PPh_3)_2$ and $H_2O$, and stoichiometrically with Rh(OH)(CO)$(PPh_3)_2$ in the absence of $H_2O$.

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Synthesis of N,N-Dimethylacetamide from Carbonylation of Trimethylamine by Rhodium(I) Complex Under Anhydrous Condition

  • Hong, Jang-Hwan
    • Journal of the Chosun Natural Science
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    • v.8 no.4
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    • pp.235-243
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    • 2015
  • Rhodium(I)-complex of $[Rh(CO)_2I_2{^-}]$ catalyzed carbonylation of anhydrous-trimethylamine in the presence of methyl iodide to give DMAC (N,N-dimethylacetamide) in no solvent. The catalyst had been reused 20 times, the analyses and distillation of collected products showed that the yields of DMAC, MAA (N-methylacetamide), and DMF (N,N-dimethylformamide) were 82.3%, 12.6%, and 4.4%. The conversion rate of trimethylamine was 99 % and the selectivity of DMAC was 82.3% with TON (Turnover Number) of 700. Stepwise procedure of inner-sphere reductive elimination for the formation of DMAC was suggested instead of acyl iodide intermediate.

Effects of chronic caloric restriction on kidney and heart redox status and antioxidant enzyme activities in Wistar rats

  • Dutra, Marcio Ferreira;Bristot, Ivi Juliana;Batassini, Cristiane;Cunha, Nubia Broetto;Vizuete, Adriana Fernanda Kuckartz;Souza, Daniela Fraga De;Moreira, Jose Claudio Fonseca;Goncalves, Carlos-Alberto
    • BMB Reports
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    • v.45 no.11
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    • pp.671-676
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    • 2012
  • Caloric restriction (CR) has been associated with health benefits and these effects have been attributed, in part, to modulation of oxidative status by CR; however, data are still controversial. Here, we investigate the effects of seventeen weeks of chronic CR on parameters of oxidative damage/modification of proteins and on antioxidant enzyme activities in cardiac and kidney tissues. Our results demonstrate that CR induced an increase in protein carbonylation in the heart without changing the content of sulfhydryl groups or the activities of superoxide dismutase and catalase (CAT). Moreover, CR caused an increase in CAT activity in kidney, without changing other parameters. Protein carbonylation has been associated with oxidative damage and functional impairment; however, we cannot exclude the possibility that, under our conditions, this alteration indicates a different functional meaning in the heart tissue. In addition, we reinforce the idea that CR can increase CAT activity in the kidney. Moreover, CR caused an increase in CAT activity in kidney, without changing other parameters. Protein carbonylation has been associated with oxidative damage and functional impairment; however, we cannot exclude the possibility that, under our conditions, this alteration indicates a different functional meaning in the heart tissue. In addition, we reinforce the idea that CR can increase CAT activity in the kidney.

Syntheses of Amide Bonds and Activations of N-C(sp3) Bonds

  • Hong, Jang-Hwan
    • Journal of the Chosun Natural Science
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    • v.10 no.4
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    • pp.175-191
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    • 2017
  • In organic chemistry amide synthesis is performed through condensation of a carboxylic acid and an amine with releasing one equivalent of water via the corresponding ammonium carboxylate salt. This method is suffering from tedious processes and poor atom-economy due to the adverse thermodynamics of the equilibrium and the high activation barrier for direct coupling of a carboxylic acid and an amine. Most of the chemical approaches to amides formations have been therefore being developed, they are mainly focused on secondary amides. Direct carbonylations of tertiary amines to amides have been an exotic field unresolved, in particular direct carbonylation of trimethylamine in lack of commercial need has been attracted much interests due to the versatile product of N,N-dimethylacetamide in chemical industries and the activation of robust N-C($sp^3$) bond in tertiary amine academically. This review is focused mainly on carbonylation of trimethylamine as one of the typical tertiary amines by transition metals of cobalt, rhodium, platinum, and palladium including the role of methyl iodide as a promoter, the intermediate formation of acyl iodide, the coordination ability of trimethylamine to transition metal catalysts, and any possibility of CO insertion into the bond of Me-N in trimethylamine. In addition reactions of acyl halides as an activated form of acetic acid with amines are reviewed in brief since acyl iodide is suggested as a critical intermediate in those carbonylations of trimethylamine.