2216-67-3Relevant academic research and scientific papers
Additive-freeN-methylation of amines with methanol over supported iridium catalyst
Liu, Xiang,Loh, Teck-Peng,Qiang, Wenwen,Wang, Jing,Ye, Sen,Zhu, Longfei
, p. 3364 - 3375 (2021/06/06)
An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-freeN-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOxand ZnO support also promoted its high reactivity. The selectivity of this catalyticN-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation ofN,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production ofN-methylated amines. With optimal flow rates and amine concentrations, a variety ofN-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production ofN-methylamines with this cost-effective chemical process.
A Metal-Free Direct Arene C?H Amination
Wang, Tao,Hoffmann, Marvin,Dreuw, Andreas,Hasagi?, Edina,Hu, Chao,Stein, Philipp M.,Witzel, Sina,Shi, Hongwei,Yang, Yangyang,Rudolph, Matthias,Stuck, Fabian,Rominger, Frank,Kerscher, Marion,Comba, Peter,Hashmi, A. Stephen K.
supporting information, p. 2783 - 2795 (2021/04/05)
The synthesis of aryl amines via the formation of a C?N bond is an essential tool for the preparation of functional materials, active pharmaceutical ingredients and bioactive products. Usually, this chemical connection is only possible by transition metal-catalyzed reactions, photochemistry or electrochemistry. Here, we report a metal-free arene C?H amination using hydroxylamine derivatives under benign conditions. A charge transfer interaction between the aminating reagents TsONHR and the arene substrates enables the chemoselective amination of the arene, even in the presence of various functional groups. Oxygen was crucial for an effective conversion and its accelerating role for the electron transfer step was proven experimentally. In addition, this was rationalized by a theoretical study which indicated the involvement of a dioxygen-bridged complex with a “Sandwich-like” arrangement of the aromatic starting materials and the aminating agents at the dioxygen molecule. (Figure presented.).
Direct ortho-Selective Amination of 2-Naphthol and Its Analogues with Hydrazines
Jia, Lei,Tang, Qiang,Luo, Meiming,Zeng, Xiaoming
, p. 5082 - 5091 (2018/05/15)
Described herein is a regioselective ortho-amination of 2-naphthol and its analogues with substituted hydrazines. It provides a direct methodology for the synthesis of N-arylaminated naphthol derivatives without the formation of related 1,1′-biaryl-2,2′-diamine or carbazole byproducts. Specifically, using N,N-disubstituted hydrazine precursors, N-unsubstituted ortho-aminated derivatives and related secondary amines can be formed in ethylene glycol in moderate to excellent yields. Variation of substrates to N,N′-diarylhydrazines and N-methyl-N,N′-diarylhydrazines led to N-aryl-1-amino-2-naphthol compounds. It is noted that biologically interesting indazole motifs can be facilely created by the reaction of N,N′-dialkylhydrazines with 2-naphthols. These ortho-amination reactions have the advantage of one-pot operation without the use of transition metal catalysts.
A new method for N-N bond cleavage of N,N-disubstituted hydrazines to secondary amines and direct ortho amination of naphthol and its analogues
Tang, Qiang,Zhang, Chao,Luo, Meiming
, p. 5840 - 5841 (2008/09/19)
An unexpected reaction of N,N-disubstituted hydrazine with naphthol and its analogues under simply thermal conditions has been disclosed. 2-Naphthol reacted with various N,N-disubstituted hydrazines under argon to afford 1-amino-2-naphthol and the corresponding secondary amines in excellent yields. Ortho amination of 2-naphthols, hydroxyquinoline, and naphthalenamine occurred when they reacted with N-methyl-N-phenylhydrazine. Copyright
AMINODEMETHOXYLATION IN QUINOLINES AND NAPHTHALENES
Terenin, V. I.,Gerasimenko, V. A.,Nikishova, N. G.,Kurts, A. L.,Afanas'eva, T. A.,Bundel', Yu. G.
, p. 1890 - 1896 (2007/10/02)
Substitution of the methoxy group in inactivated aromatic and heterocyclic substrates by alkylamines takes place by bimolecular nucleophilic substitution at a saturated carbon atom with the formation of phenolic intermediates and subsequent substitution of the hydroxyl group by the alkylamino group.In the temperature range between 150 and 200 deg C in the presence of ammonium chloride the substitution of the hydroxy group in 1- and 2-hydroxynaphthalenes and 6-, 7-, and 8-hydroxyquinolines, and of the methoxy group in 1- and 2-methoxynaphthalenes and 6-, 7-, and 8-methoxyquinolines takes place almost quantitatively.
ONE-POT CHEMOSELECTIVE REDUCTIVE ALKYLATION OF NITROARENES: A NEW GENERAL METHOD OF SYNTHESIS OF ALKYLANILINES.
Bartoli, Giuseppe,Bosco, Marcella,Pozzo, Renato Dal,Petrini, Marino
, p. 4221 - 4226 (2007/10/02)
A New facile and general synthesis of alkylanilines by one-pot reductive alkylation of nitroarenes is reported.This method is based on the "in situ" reduction by hydrides (LiAlH4 or NaBH4) in the presence of catalytic amounts of Pd/C, of nitronate adducts arising from the conjugate addition of Grignard reagents to mononitroarenes.LiAlH4 showed to be a more efficient but less selective reducing agent than NaBH4.The reaction can be successfully applied to mono, homo and hetero bicyclic systems and allows to introduce a large variety of alkyl chains without isomerisation phenomena.
Recyclization of 3-Alkyl- and 1,3-Dialkylisoquinolinium Salts to Naphthylamines
Kost, A. N.,Terenin, V. I.,Yudin, L. G.,Sagitullin, R. S.
, p. 965 - 969 (2007/10/02)
3-Methyl- and 3-benzylisoquinolinium salts undergo rearrangement to 2-alkylaminonaphthalenes under the influence of alcohol solutions of alkylamines.The rearrangement of 1,3-dimethyl- and 1-methyl-3-benzylisoquinolinium salts leads to both 1- and 2-alkylaminonaphthalenes with predominance of the former.
Electrochemical Reactions. Part 23. Intramolecular Radical Substitution during the Reduction of 2-Halogeno-N-methyl-N-naphthylbenzamides
Grimshaw, James,Haslett, Reginald J.
, p. 657 - 660 (2007/10/02)
Phenyl radical intermediates formed by the reductive cleavage of the carbon-halogen bond in 2-halogeno-N-methyl-N-(1-naphthyl)benzamides undergo intramolecular substitution to give N-methyl-2-(1-naphthyl)benzamide, and no N-methylbenzophenanthridone is formed.Reduction of 2-halogeno-N-methyl-N-(2-naphthyl)benzamides gives N-methyl-2-(2-naphthyl)benzamide, N-methylbenzophenanthridone, and N-methylbenzophenanthridone.These results complete our comparison of this electrochemical reaction with related radical Pschorr cyclisations.Further reduction of these initial reaction products occurs that only qualitative conclusions can be drawn from the product yields.
