- Cercosporin-photocatalyzed sp3 (C-H) activation for the synthesis of pyrrolo[3,4-: C] quinolones
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We reported a new method that visible light along with cercosporin, one of the naturally occurring perylenequinonoid pigments with excellent properties of photosensitization, photocatalyzed sp3 (C-H) activation for the synthesis of pyrrolo[3,4-
- Li, Jia,Bao, Wenhao,Zhang, Yan,Rao, Yijian
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supporting information
p. 8958 - 8962
(2019/10/28)
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- Eco-friendly acetylcholine-carboxylate bio-ionic liquids for controllable: N-methylation and N-formylation using ambient CO2 at low temperatures
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Catalytic fixation of CO2 to produce valuable fine chemicals is of great significance to develop a green and sustainable circulation of excessive carbon in the environment. Herein, a series of non-toxic, biodegradable and recyclable acetylcholine-carboxylate bio-ionic liquids with different cations and anions were simply synthesized for producing formamides and methylamines using atmospheric CO2 as a carbon source, and phenylsilane as a hydrogen donor. The selectivity toward products was tuned by altering the reaction temperature under solvent or solvent-free conditions. N-Methylamines (ca. 96% yield) were obtained in acetonitrile at 50 °C, while N-formamides (ca. 99% yield) were attained without a solvent at 30 °C. The established bio-ionic liquid catalytic system found a wide range of applicability in substrates and possessed a high potentiality in scale-up to gram-grade production. The developed catalytic system was fairly stable, which could be easily reused without an apparent loss of reactivity, possibly due to the strong electrostatic interactions between the cation and anion. The combination of experimental and computational results explicitly elucidated the reaction mechanism: PhSiH3 activated by a bio-IL was favorable for the formation of silyl formate from hydrosilylation of CO2, followed by a reaction with an amine to give an N-formamide, while an N-methylamine was formed by further hydrosilylation of the N-formamide.
- Zhao, Wenfeng,Chi, Xiaoping,Li, Hu,He, Jian,Long, Jingxuan,Xu, Yufei,Yang, Song
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supporting information
p. 567 - 577
(2019/02/14)
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- Oxidative Cyclization Synthesis of Tetrahydroquinolines and Reductive Hydrogenation of Maleimides under Redox-Neutral Conditions
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A redox-neutral reaction without using any external oxidant and reductant in one pot is described. By combining a Ru(bpy)32+ photocatalyst and cobaloxime catalyst, a number of tertiary anilines can be oxidized by Ru(bpy)3
- Yang, Xiu-Long,Guo, Jia-Dong,Lei, Tao,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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supporting information
p. 2916 - 2920
(2018/05/29)
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- Metal-Free Geminal Difunctionalization of Diazocarbonyl Compounds: A One-Pot Multicomponent Strategy for the Construction of α,β-Diamino Carbonyl Derivatives
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An unprecedented three-component domino oxidative coupling of diazocompounds for the efficient synthesis of α-azido-β-amino esters with non-activated dimethylamino compounds and simple TMSN3 was achieved. The main features of this method include metal-free catalysis, satisfactory functional group tolerance, general applicability in complex molecule architectures, and excellent diastereoselectivity in the presence of chiral auxiliaries. In addition, several related control experiments have been conducted to investigate the reaction mechanism.
- Zhu, Dan,Yao, Yuan,Zhao, Rong,Liu, Yang,Shi, Lei
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supporting information
p. 4805 - 4809
(2018/03/21)
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- N-Mannich Bases of Aromatic Heterocyclic Amides: Synthesis via Copper-Catalyzed Aerobic Cross-Dehydrogenative Coupling under Ambient Conditions
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An efficient and facile method to synthesize N-Mannich bases has been developed using an inexpensive copper(I) bromide/air catalyst system at ambient temperature. A cross-dehydrogenative coupling of N,N-dimethylarylamines occurs efficiently with aromatic heterocyclic amides (oxindoles, isatins), cyclic amides (lactams), simple amides (benzamide), as well as imides (succinimide, phthalimide) to furnish the corresponding amidated/imidated derivatives in good to excellent yields. Preliminary mechanistic and isotope-labeling studies suggest the reaction follows a radical pathway and involves an iminium ion intermediate.
- Singh, Shailendra K.,Chandna, Nisha,Jain, Nidhi
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supporting information
p. 1322 - 1325
(2017/03/23)
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- Ruthenium-catalyzed alkylation of indoles with tertiary amines by oxidation of a sp3 CH bond and lewis acid catalysis
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Ruthenium porphyrins (particularly [Ru(2,6-Cl2tpp)CO]; tpp = tetraphenylporphinato) and RuCl3 can act as oxidation and/or Lewis acid catalysts for direct C-3 alkylation of indoles, giving the desired products in high yields (up to 82
- Wang, Ming-Zhong,Zhou, Cong-Ying,Wong, Man-Kin,Che, Chi-Ming
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supporting information; experimental part
p. 5723 - 5735
(2010/08/20)
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- Stereochemistry of β-deuterium isotope effects on amine basicity
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Secondary β-deuterium isotope effects on amine basicities are measured using a remarkably precise NMR titration method. Deuteration is found to increase the basicity of methylamine, dimethylamine, benzylamine, N,N-dimethylaniline, 2-methyl-2-azanorbornane, and pyrrolizidine. The increase in dimethylamine arises entirely from enthalpy, contrary to a previous report. The method permits a determination of intramolecular isotope effects in 1-benzyl-4-methylpiperidine and 2-benzyl-2-azanorbornane. It is found that deuteration has a larger isotope effect when either antiperiplanar or synperiplanar to a lone pair, but the synperiplanar effect is smaller, as confirmed by computations. The isotope effect is attributed to a lowered zero-point energy of a C-H bond adjacent to an amine nitrogen, arising from delocalization of either a syn or an anti lone pair, and with no detectable angle-independent inductive effect.
- Perrin, Charles L.,Ohta, Brian K.,Kuperman, Joshua,Liberman, Jordan,Erdelyi, Mate
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p. 9641 - 9647
(2007/10/03)
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- β-deuterium Isotope Effects on Amine Basicity, Inductive and Stereochemical
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Secondary β deuterium isotope effects on acidity constants of ammonium ions are measured using a remarkably precise NMR titration method. Deuteration is found to increase the basicity of methylamine, dimethylamine, benzylamine, and N,N-dimethylaniline. The effect is attributed to a lowered zero-point energy of a CH bond adjacent to an amine nitrogen. The method permits a determination of the stereochemical dependence of the isotope effect in a locked piperidine, and it is found that deuteration is more effective when antiperiplanar to a lone pair. The values are consistent with a cos2 dependence on dihedral angle, with no detectable angle-independent inductive effect. Copyright
- Perrin, Charles L.,Ohta, Brian K.,Kuperman, Joshua
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p. 15008 - 15009
(2007/10/03)
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- On isotope effects for the cytochrome P-450 oxidation of substituted N,N-dimethylanilines
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Isotope effects were determined for the oxidative demethylation of the substituted N-methyl-N-(trideuteriomethyl)anilines 1a-d, and the corresponding N,N-bis(dideuteriomethyl)anilines 2a-d, by microsomal cytochrome P-450. The pairs of p-cyano- and p-nitro
- Dinnocenzo,Karki,Jones
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p. 7111 - 7116
(2007/10/02)
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- THE CONFORMATION OF N-NITROSO-N-METHYLANILINE FROM MICROWAVE SPECTROSCOPY
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The low resolution microwave spectrum of N-nitroso-N-methylaniline shows only one series of μa R-branch bands.The value of B + C = 1584.6 MHz is consistent with this being the rotamer in which the benzene ring is exo to the nitroso group.The high resolution microwave spectra of the normal, CD3 and two meta-D species show conclusively that this rotamer has a non-planar heavy atom skeleton.The rotational constants, the quantity Δc (= Ia + Ib - Ic) and the substitution coordinates are well reproduced by a molecular model based on the structures of aniline and N,N-dimethylnitrosamine in which the plane of the benzene ring is twisted by 30 deg relative to the heavy atom plane of the rest of the molecule.
- Caminati, W.,Giumanini, A. G.
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p. 255 - 262
(2007/10/02)
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- N-DEMETHYLATION OF N,N-DIMETHYLANILINES BY PHOTOEXCITED 3-NITROCHLOROBENZENE
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The title reaction proceeds via initial electron transfer (rather than hydrogen atom transfer) from the amine to the photoexcited nitro compound, as demonstrated by methoxy substitution in the substrate and absence of CH3/CD3-discrimination.
- Doepp, Dietrich,Heufer, Joerg
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p. 1553 - 1556
(2007/10/02)
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