Supported Gold Nanoparticles for Efficient α‐Oxygenation of Secondary and Tertiary Amines into Amides

Jin, Xiongjie; Kataoka, Kengo; Yatabe, Takafumi; Yamaguchi, Kazuya; Mizuno, Noritaka

doi:10.1002/anie.201602695

Cited by 82 publications

(49 citation statements)

References 47 publications

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“…Ther eaction proceeded smoothly when N,N-dimethylbenzylamine derivatives with electron-donating groups were used as the substrates,a nd the corresponding formamides were obtained in high yields (Table 3b, 15 and 16). Although N,N-dimethylbenzylamine derivatives with electron-withdrawing groups were less effective,the oxygenation was almost complete when the reaction time was increased to 24 h ( Table 3b, [17][18][19][20][21][22]. They ields of formamides were unsatisfactory with some kinds of N,N-dimethylamines,s uch as N,N-dimethylisopropylamine and N,N-dimethylbutylamine,u nder the standard conditions.F or these substrates, the corresponding formamides were obtained in good yields by using 2,4,4-trimethyl-2-oxazoline and increasing the amount of catalyst as with 1-methylpyrrolidine (Table 3b, 23 and 24).…”

Section: Angewandte Chemiementioning

confidence: 99%

“…[20] ii)Iminium cation intermediates produced by oxidation at the amethyl groups are thermodynamically unstable compared with the multi-substituted iminium cations.P reviously,w e reported that cyclic and linear a-methylene positions are selectively oxygenated in aerobic a-oxygenation of tertiary amines catalyzed by supported gold nanoparticles. [21] iii)Unlike cross-dehydrogenative coupling, a-oxygenation requires additional oxidation of hemiaminal intermediates,p roduced by hydration of the iminium cations.Wepreviously developed regioselective a-cyanation and a-alkynylation at N-methyl positions of tertiary amines by MnO 2 -based catalysts. [6,7] However,aMnO 2 -catalyzed methyl-selective a-oxygenation strategy failed because of the poor catalytic activity of MnO 2 for the hemiaminal oxidation.…”

Section: Introductionmentioning

confidence: 99%

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Methyl‐Selective α‐Oxygenation of Tertiary Amines to Formamides by Employing Copper/Moderately Hindered Nitroxyl Radical (DMN‐AZADO or 1‐Me‐AZADO)

et al. 2019

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Methyl‐selective α‐oxygenation of tertiary amines is a highly attractive approach for synthesizing formamides while preserving the amine substrate skeletons. Therefore, the development of efficient catalysts that can advance regioselective α‐oxygenation at the N‐methyl positions using molecular oxygen (O2) as the terminal oxidant is an important subject. In this study, we successfully developed a highly regioselective and efficient aerobic methyl‐selective α‐oxygenation of tertiary amines by employing a Cu/nitroxyl radical catalyst system. The use of moderately hindered nitroxyl radicals, such as 1,5‐dimethyl‐9‐azanoradamantane N‐oxyl (DMN‐AZADO) and 1‐methyl‐2‐azaadamanane N‐oxyl (1‐Me‐AZADO), was very important to promote the oxygenation effectively mainly because these N‐oxyls have longer life‐times than less hindered N‐oxyls. Various types of tertiary N‐methylamines were selectively converted to the corresponding formamides. A plausible reaction mechanism is also discussed on the basis of experimental evidence, together with DFT calculations. The high regioselectivity of this catalyst system stems from steric restriction of the amine‐N‐oxyl interactions.

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Section: Angewandte Chemiementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Methyl‐Selective α‐Oxygenation of Tertiary Amines to Formamides by Employing Copper/Moderately Hindered Nitroxyl Radical (DMN‐AZADO or 1‐Me‐AZADO)

et al. 2019

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“…以 1a (10 g, 50.7 mmol)作底物, 氟硼酸锌水合物(1.7 g, 5.0 mmol, 10 mol%)为催化剂, 乙腈(100 mL)作为溶剂, 100 ℃回流反与已报道的锌催化酮与盐酸羟胺的一步法反应体系相比 [20,22] , 本体系反应条件较温和、催化剂廉价易得、产物收率高, 为酮与盐酸羟胺的一步法贝克曼重排反应提供了一种"锌"方法. [23] 、 1b [25] 、 1c [25] 、 1d [26] 、1e [23] 、1f [23] 、1g [23] 、1h [23] 、1i [23] [28] 、2b [25] 、2c [25] 、2e [29] 、2f [30] 、2g [30] 、2h [30] 、 2i [31] 、2j [32] 均与文献报道中核磁数据相符. …”

Section: G 级贝克曼重排反应unclassified

Zn-Catalyzed Beckmann Rearrangement Reaction

Sun¹,

Yao²,

Zhang³

et al. 2018

Chin. J. Org. Chem.

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The Beckmann rearrangement reactions generally require strong acids, and always suffer from harsh conditions and serious environmental pollutions which go against the principle of green chemistry. Base on the green zinc catalyst, highly efficient catalytic reaction of ketoxime by Beckmann rearrangement was developed. The acid-additives-free reactions proceed under mild conditions, and show broad functional-group compatibility. Moreover, through this highly active and available zinc catalyst, the Beckmann rearrangement reaction is further extended to a one-pot protocol using ketone and hydroxylamine hydrochloride as reactive materials. Featuring high atom-economy and broad substrate scopes, this novel method provided an attractive route for the Beckmann rearrangement reactions.

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“…15,40,41 Tertiary amine is the hydrophilic head group of MDH. Therefore, it is likely that MLP delivery of siPLK1 would increase uptake of siPLK1 by tumor cells.…”

Section: Intracellular Uptake Of Mlp/sirna By C6 Cellsmentioning

confidence: 99%

Hypoxia-responsive ionizable liposome delivery siRNA for glioma therapy

Liu¹,

Zhang²,

Xie³

et al. 2017

IJN

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Here, we report the hypoxia-responsive ionizable liposomes to deliver small interference RNA (siRNA) anticancer drugs, which can selectively enhance cellular uptake of the siRNA under hypoxic and low-pH conditions to cure glioma. For this purpose, malate dehydrogenase lipid molecules were synthesized, which contain nitroimidazole groups that impart hypoxia sensitivity and specificity as hydrophobic tails, and tertiary amines as hydrophilic head groups. These malate dehydrogenase molecules, together with DSPE-PEG2000 and cholesterol, were self-assembled into O′ 1 ,O 1 -(3-(dimethylamino)propane-1,2-diyl) 16-bis(2-(2-methyl-5-nitro-1 H -imidazol-1-yl)ethyl) di(hexadecanedioate) liposomes (MLP) to encapsulate siRNA through electrostatic interaction. Our study showed that the MLP could deliver polo-like kinase 1 siRNA (siPLK1) into glioma cells and effectively enhance the cellular uptake of MLP/siPLK1 because of increased positive charges induced by hypoxia and low pH. Moreover, MLP/siPLK1 was shown to be very effective in inhibiting the growth of glioma cells both in vitro and in vivo. Therefore, the MLP is a promising siRNA delivery system for tumor therapy.

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Supported Gold Nanoparticles for Efficient α‐Oxygenation of Secondary and Tertiary Amines into Amides

Cited by 82 publications

References 47 publications

Methyl‐Selective α‐Oxygenation of Tertiary Amines to Formamides by Employing Copper/Moderately Hindered Nitroxyl Radical (DMN‐AZADO or 1‐Me‐AZADO)

Methyl‐Selective α‐Oxygenation of Tertiary Amines to Formamides by Employing Copper/Moderately Hindered Nitroxyl Radical (DMN‐AZADO or 1‐Me‐AZADO)

Zn-Catalyzed Beckmann Rearrangement Reaction

Hypoxia-responsive ionizable liposome delivery siRNA for glioma therapy

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