- Nickel Complexes Bearing N,N,O-Tridentate Salicylaldiminato Ligand: Efficient Catalysts for Imines Formation via Dehydrogenative Coupling of Primary Alcohols with Amines
-
Treatment of salicylaldiminato ligand L1H-L2H (L1H = 2,4-di-tert-butyl-6-((quinolin-8-ylimino)methyl)phenol; L2H = 2,4-di-tert-butyl-6-(((2-(diethylamino)ethyl)imino)methyl)phenol) with Ni(OAc)2·4H2O in refluxing ethanol afforded nickel complexes [(L1)Ni(OAc)] (1) and [(L2)Ni(OAc)] (2), respectively. Reaction of L3H (L3H = (2,4-di-tert-butyl-6-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenol)) with Ni(OAc)2·4H2O in the presence of excess triethylanmine gave the dual ligands coordinated nickel complex [(L2)2Ni] (3). Complexes 1-3 were well characterized by high-resolution mass spectrometry, infrared spectroscopy, elemental analysis, and X-ray diffraction analysis. All the three Ni(II) complexes exhibited efficient activity and good selectivity in the acceptorless dehydrogenative coupling of alcohols and amines to produce imines and diimines. The present protocol provides an atom-economical and sustainable route for the synthesis of various imine derivatives by employing an earth-abundant nickel salt and easily prepared salicylaldiminato ligands.
- Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Lu, Guo-Liang,Zhang, Junhua,Zhang, Xiaoying
-
p. 3843 - 3853
(2021/11/18)
-
- Switchable Imine and Amine Synthesis Catalyzed by a Well-Defined Cobalt Complex
-
Switchable imine and amine synthesis catalyzed by a tripodal ligand-supported well-defined cobalt complex is presented herein. A large variety of primary alcohols and amines were selectively converted to imines or amines in good to excellent yields. It is discovered that the base plays a crucial role on the selectivity. A catalytic amount of base leads to the imine formation, while an excess loading of base results in the amine product. This strategy on product selectivity also strongly depends on the organometallic catalysts in use. We expect that the present study could provide useful insights toward selective organic synthesis and catalyst design.
- Paudel, Keshav,Xu, Shi,Hietsoi, Oleksandr,Pandey, Bedraj,Onuh, Chuka,Ding, Keying
-
supporting information
p. 418 - 426
(2021/02/01)
-
- Base-mediated cascade amidination/: N -alkylation of amines by alcohols
-
A base-mediated cascade amidination/N-alkylation reaction of amines by alcohols has been developed. For the first time, nitriles have been identified as an efficient and benign water acceptor reagent in N-alkylation. Notably, the procedure tolerates a series of functional groups, such as methoxyl, halo, vinyl and hetero groups, providing a convenient method to construct different substituted diamino compounds, 15N labeled amine and could be scaled up to 1 mol scale offering 138.7 g of the desired product in good yield in one-pot. Mechanistic studies provided strong evidence for the amidination of amines with nitriles facilitated by t-BuOK.
- Hu, Mao-Lin,Jia, Xiaofei,Liang, Zuyu,Lu, Fenghong,Zhang, Chunyan,Zhang, Guoying
-
supporting information
p. 10489 - 10492
(2020/10/02)
-
- Direct access to: N -alkylated amines and imines via acceptorless dehydrogenative coupling catalyzed by a cobalt(ii)-NNN pincer complex
-
A simple, phosphine-free Co(ii)-NNN pincer complex catalyzed direct N-alkylation of anilines with alcohols via hydrogen auto-transfer (HA) and selective acceptorless dehydrogenative coupling (ADC) of benzylamines with alcohols affording imines with the liberation of molecular hydrogen and water is reported.
- Midya, Siba P.,Pitchaimani, Jayaraman,Landge, Vinod G.,Madhu, Vedichi,Balaraman, Ekambaram
-
p. 3469 - 3473
(2018/07/29)
-
- Site-Selective Conversion of Azido Groups at Carbonyl α-Positions to Diazo Groups in Diazido and Triazido Compounds
-
This paper reports on the selective conversion of alkyl azido groups at the carbonyl α-position to diazo compounds. Through β-elimination of dinitrogen, followed by hydrazone formation/decomposition, α-azidocarbonyl moieties were transformed into α-diazo carbonyl groups in one step. As these reaction conditions do not involve aryl or general alkyl azides, site-selective conversions of di- and triazides were achieved. Through this method, the successive site-selective conjugation of the triazido molecule with three different components is demonstrated.
- Yokoi, Taiki,Tanimoto, Hiroki,Ueda, Tomomi,Morimoto, Tsumoru,Kakiuchi, Kiyomi
-
p. 12103 - 12121
(2018/10/09)
-
- Hemilabile N-heterocyclic carbene (NHC)-nitrogen-phosphine mediated Ru (II)-catalyzed N-alkylation of aromatic amine with alcohol efficiently
-
Based on the hemilability, a novel N-heterocyclic carbene (NHC)-nitrogen-phosphine ligand (1) was synthesized, and the combination of it with [Ru(COD)Cl2]n showed the high activity and selectivity with a low Ru loading of 0.1% for the N-alkylation of amine with alcohol. Especially, for these substrates with pyridine backbone, even if the catalyst loading was as low as 0.01%, good yields (81–95%) of the desired products were achieved.
- Yu, Xiao-Jun,He, Hai-Yu,Yang, Lei,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua,Li, Rui-Xiang
-
-
- Cobalt-Catalyzed N-Alkylation of Amines with Alcohols
-
A well-defined nonprecious metal cobalt(II) catalyst based on a pincer PNP ligand has been employed for the efficient N-alkylation of both aromatic and aliphatic amines with alcohols. A subtle change of reaction conditions (simply adding 4 ? molecular sieves) was observed to readily switch the resulting products (amines vs imines) with high chemoselectivity. A range of alcohols and amines including both aromatic and aliphatic substrates were efficiently converted to secondary amines in good-to-excellent yields when 2 mol % cobalt catalyst was used. Additional experiments indicate that a hydrogen-borrowing mechanism is responsible for the tandem acceptorless dehydrogenation/condensation/hydrogenation process.
- Zhang, Guoqi,Yin, Zhiwei,Zheng, Shengping
-
supporting information
p. 300 - 303
(2016/02/03)
-
- Ruthenium(II) carbonyl complexes designed with arsine and PNO/PNS ligands as catalysts for N-alkylation of amines via hydrogen autotransfer process
-
A series of phosphine-functionalized hydrazone/thiosemicarbazone ligands and their corresponding ruthenium(II) carbonyl complexes of the type [RuCl(CO)(AsPh3)(L)] (1-5) [L = 2-(2-(diphenylphosphino)benzylidene)benzoic acid hydrazone (PNO-BHy), 2-(2-(diphenylphosphino)benzylidene)nicotinic acid hydrazone (PNO-NHy), 2-(2-(diphenylphosphino)benzylidene)-2-furoic hydrazone (PNO-FHy), 2-(2-(diphenylphosphino)benzylidene)-4-ethyl-3-thiosemicarbazone (PNS-EtTs), 2-(2-(diphenylphosphino)benzylidene)-4-cyclohexyl-3-thiosemicarbazone (PNS-CyTs)] have been synthesized based on the ligands with different electronic and steric effects. These complexes were characterized by elemental analyses and various spectral methods. The solid-state structure of the complex 4 was determined by single-crystal X-ray diffraction method. In all of the complexes, the ligand was bound to the Ru(II) center via the PNO/PNS donor atoms. All the ruthenium(II) complexes were demonstrated as highly efficient catalysts for the synthesis of secondary amines/amides by the coupling of primary amines/amides with alcohols at low catalyst loading, and the maximum yield was obtained up to 98%. The N-alkylation reaction can be readily carried out under moderate conditions, and release of water is the sole byproduct. In addition, the effects of substituents on the ligand, solvents, base and catalyst loading on the catalytic activity of the complexes have been investigated. Advantageously, only one equivalent of the alcohol was consumed in the process.
- Ramachandran, Rangasamy,Prakash, Govindan,Nirmala, Muthukumaran,Viswanathamurthi, Periasamy,Malecki, Jan Grzegorz
-
supporting information
p. 130 - 140
(2015/06/22)
-
- Cobalt-Catalyzed Alkylation of Aromatic Amines by Alcohols
-
The implementation of inexpensive, Earth-abundant metals in typical noble-metal-mediated chemistry is a major goal in homogeneous catalysis. A sustainable or green reaction that has received a lot of attention in recent years and is preferentially catalyzed by Ir or Ru complexes is the alkylation of amines by alcohols. It is based on the borrowing hydrogen or hydrogen autotransfer concept. Herein, we report on the Co-catalyzed alkylation of aromatic amines by alcohols. The reaction proceeds under mild conditions, and selectively generates monoalkylated amines. The observed selectivity allows the synthesis of unsymmetrically substituted diamines. A novel Co complex stabilized by a PN5P ligand catalyzes the reactions most efficiently. Sustainable C-N bond formation: An easily accessible Co complex efficiently catalyzes the alkylation of aromatic amines by alcohols. The mild reaction conditions permit the use of sensitive functional groups (I, Br) and the observed selective monoalkylation allows the synthesis of unsymmetrically alkylated diamines.
- R?sler, Sina,Ertl, Michael,Irrgang, Torsten,Kempe, Rhett
-
supporting information
p. 15046 - 15050
(2016/01/25)
-
- Room temperature and solvent-free iridium-catalyzed selective alkylation of anilines with alcohols
-
A bidentate iridium NHC-phosphine complex has been developed and applied to the N-monoalkylation of aromatic amines with a wide range of primary alcohols and to the N-heterocyclization of amino alcohols. This reaction resulted in high isolated product yields, even at room temperature and under solvent-free conditions. The Royal Society of Chemistry 2013.
- Li, Jia-Qi,Andersson, Pher G.
-
p. 6131 - 6133
(2013/07/26)
-
- Solvent-free preparation of N, N ′-dialkylbenzenediamines
-
A diiridium complex, stabilized by a bis(N-heterocyclic carbene) ligand, was found to be an effective precatalyst for the N,N′-dialkylation of o-, m-, and p-benzenediamine in excellent yields. Benzyl and primary aliphatic alcohols were used as alkylating reagents. Furthermore, the reactions were carried out without using any organic solvent, offering an environmentally benign process.
- Kuo, Hsin-Ya,Liao, Bei-Sih,Liu, Shiuh-Tzung
-
supporting information
p. 189 - 192
(2013/03/13)
-
- The iridium-catalyzed synthesis of symmetrically and unsymmetrically alkylated diamines under mild reaction conditions
-
An iridium catalyst - stabilized by an anionic P,N ligand - was used for the symmetrical and unsymmetrical monoalkylation of para-, meta-, and ortho-benzenediamines. Benzyl and aliphatic alcohols were used as alkylating reagents. 28 derivatives were synthesized. 14 of them are new compounds. Furthermore, the alkylation of the pharmacological important diamine Dapson (dapsone) is described. 14 dapsone derivatives were synthesized among them 9 new compounds. Copyright
- Michlik, Stefan,Hille, Toni,Kempe, Rhett
-
experimental part
p. 847 - 862
(2012/05/04)
-
- N,N′-dialkylation catalyzed by bimetallic iridium complexes containing a saturated bis-N-heterocyclic carbene (NHC) ligand
-
Reaction of the bis-aminophosphinimine [m-C6H 4(HNCH2CH2N=PPh3)] with W(CO) 6 afforded [m-C6H4{(CNCH2CH 2NH)W(CO)5}2] (2), which underwent N-alkylation with benzyl bromide to yield [m-C6H4{(CNCH 2CH2NCH2Ph)W(CO)5}2] (3). A carbene transfer reaction from W(0) to Ir(I) proceeded smoothly via the reaction of 3 with [Ir(COD)Cl]2 under mild conditions to give the diiridium(I) carbene complex [m-C6H4{(CNCH 2CH2NH)Ir(CO)2Cl}2] (4). Ligand substitution of 4 with an excess of PPh3 produced the phosphine complex 5. All complexes have been characterized by spectroscopic and elemental analyses. Complexes 2 and 5 were further confirmed by X-ray diffraction studies. Complex 4 is an efficient catalyst for the reductive N,N′-dialkylation of phenylenediamines with alcohols. The mechanistic pathway of the catalysis involving the possible synergistic effect between two metal centers is discussed.
- Kuo, Hsin-Ya,Liu, Yi-Hong,Peng, Shie-Ming,Liu, Shiuh-Tzung
-
p. 7248 - 7255,8
(2020/09/02)
-
- Synthesis of N,N′-bis-[3-alkoxy-4-(hydroxy, alkoxy, acyloxy)-phenylmethylene- and -Phenylmethyl]-1,3-phenylenediamines
-
Starting with the vanillin series aldehydes, by reaction with 1,3-phenylenediamine in absolute methanol E,E-N,N′-bis-[3-alkoxy-4- (hydroxy-, alkoxy-, acyloxy)phenylme-thylene]-1,3-phenyl-enediamines (Shiff bases) are synthesized from reduction with Na[BH(
- Dikusar,Potkin,Kozlov,Yuvchenko
-
experimental part
p. 258 - 263
(2009/08/14)
-
- Novel potassium channels modulators
-
The invention relates to compounds having the Formula (I) or a salt, or a physiologically functional derivative, or a prodrug thereof, wherein the amine substituent is in the meta or para-position to the amine moiety of the compound of Formula (I); (A) and (B) each independently represent an aromatic hydrocarbon group which optionally contains one or more heteroatoms selected from the group consisting of S, O and N, wherein the heteroatom N is optionally substituted with R5, and/or the heteroatom S is optionally bonded to ═O or (═O)2;
- -
-
-
- A selective reductive amination of aldehydes by the use of Hantzsch dihydropyridines as reductant
-
Direct reductive amination of an aldehyde was carried out using a Hantzsch dihydropyridine as the reductant in the presence of a catalytic amount of scandium triflate. The reaction was highly selective towards aldehydes over ketones, and other reducible functional groups did not affect the reaction.
- Itoh, Takashi,Nagata, Kazuhiro,Miyazaki, Michiko,Ishikawa, Hiroyuki,Kurihara, Ayako,Ohsawa, Akio
-
p. 6649 - 6655
(2007/10/03)
-