2216-67-3Relevant articles and documents
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.
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.
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.
