17377-95-6Relevant academic research and scientific papers
Helquats as Promoters of the Povarov Reaction: Synthesis of 1,2,3,4-Tetrahydroquinoline Scaffolds Catalyzed by Helicene-Viologen Hybrids
?aman, David,?vec, Pavel,Amatov, Tynchtyk T.,Císa?ová, Ivana,Pohl, Radek,Pospí?il, Lubomír,Reyes-Gutiérrez, Paul E.,Teply, Filip
, (2020)
Helquats (HQs) are structurally linked to helicenes and viologens, and they represent an attractive field of research in chemistry and medicinal chemistry. In the present work they were used as catalysts for the synthesis of 1,2,3,4-tetrahydroquinolines in good yields by the Povarov reaction. The substrate scope and the capability of different helquats to promote Povarov reactions are demonstrated. Studies to elucidate mechanistic details revealed that helquats act as single-electron transfer oxidants through a cation-radical mechanism. The screening of the catalytic activity of HQs confirmed that an active HQ must have a LUMO energy below ?8.67 eV and the standard redox potential higher (less negative) than ?1.2 V vs. the ferrocene/ferrocenium redox couple.
Spectroscopic evidence of a free-radical mechanism in the reduction of Schiff bases by formic acid
Bianchini, Roberta,Forte, Claudia,Musumarra, Giuseppe,Pinzino, Calogero,Sergi, Caterina
, p. 6907 - 6916 (1997)
The unprecedented direct detection of the free radical intermediate 7 in the reduction of Schiff bases 2 to the corresponding amines by formic acid using the EPR technique is reported. Monitoring the same reaction by NMR, line broadenings and signal shift
Sulfonated multiwalled carbon nanotubes (MWCNTs) as a new, efficient, and recyclable heterogeneous nanocatalyst for the synthesis of amines
Doroodmand, M. M.,Sobhani, S.,Ashoori, A.
, p. 701 - 707,7 (2012)
Sulfonated multiwalled carbon nanotubes (MWCNTs) were synthesized by chemical vapor deposition (CVD) as a new and facile one-pot method using acetylene (as the CNT precursor), thiophene (as the sulfur precursor), and ferrocene (for in situ liberation of metal nanoparticles as the CNT nanocatalyst). A low catalytic amount of the resulting sulfonated MWCNTs with a turnover number (TON) up to 980 and a turnover frequency (TOF) up to 11 160 h-1 was utilized as a new and recyclable heterogeneous nanocatalyst for the efficient one-pot synthesis of various amines (secondary and tertiary) by direct reductive amination of aldehydes and ketones using NaBH4. The catalyst was easily isolated from the reaction mixture by simple filtration and reused at least five times without significant degradation in activity.
REDUCTION OF IMINES BY CLUSTER (fE4s4(SR)4)3-
Mashino, Tadahiko,Nagano, Tetsuo,Hirobe, Masaaki
, p. 5113 - 5116 (1983)
The clusters (Fe4S4(sr)4)n- (n=3) generated electrochemically reduced imines to amines in a CH3CN/CH3OH solution.The correlations between the redox potentials of imines and the yields of the reductions were examined.
C-N bond formation between alcohols and amines using an iron cyclopentadienone catalyst
Rawlings, Andrew J.,Diorazio, Louis J.,Wills, Martin
, p. 1086 - 1089 (2015)
An iron-tetraphenylcyclopentadienone tricarbonyl complex is demonstrated to act as a precursor of a catalyst for the formation of C-N bonds through a "hydrogen-borrowing" reaction between amines and alcohols.
Samarium-induced iodine-catalyzed reduction of imines: Synthesis of amine derivatives
Banik, Bimal K.,Zegrocka, Oliwia,Banik, Indrani,Hackfeld, Linda,Becker, Frederick F.
, p. 6731 - 6734 (1999)
Samarium metal induced iodine-catalyzed reduction of the imines towards the synthesis of secondary amines was investigated. The imines derived from aromatic amines produced monoamines whereas imines from arylalkyl amines gave diamines in good yield.
The NMR Spectra of the Porphyrins 17. Metalloporphyrins as Diamagnetic Shift Reagents, Structural and Specificity Studies
Abraham, Raymond J.,Bedford, Geoffrey R.,Wright, Brian
, p. 45 - 52 (1982)
The nature of the metalloporphyrin-ligand complexes produced by zinc, magnesium and cobalt porphyrins with basic ligands has been investigated using the diamagnetic ring current shifts of the porphyrin on the ligand protons.The metal to nitrogen bond lengths in some metallo-meso-tetraphenylporphyrin (pyridine) complexes have been determined and compared with the data of the crystalline complexes.The geometry of the Zn meso-tetraphenylporphyrin complexes with 2-picoline, quinoline and isoquinoline has been investigated.Steric interactions between the ligand and the porphyrin in 2-picoline and quinoline produce a dramatic increase in the Zn-N bond length when compared to the unstrained analogues pyridine and isoquinoline.This large increase is associated with comparatively minor angle distortions in the complex.The specificity of the Zn meso-tetraphenylporphyrin complexation shifts has been determined for a range of benzyl and butyl compounds.The complexation shift is linearly related to the basicity of the ligand for a wide range of basicities.
Ruthenium(II) complexes of pyridine-carboxamide ligands bearing appended benzothiazole/benzimidazole rings: Structural diversity and catalysis
Vijayan, Paranthaman,Yadav, Samanta,Yadav, Sunil,Gupta, Rajeev
, (2020)
A series of ruthenium(II) complexes (1–6) of pyridine-carboxamide ligands, HLBT/BI (HLBT = N-(benzo[d]thiazol-2-yl)picolinamide and HLBI = N-(1H-benzo[d]imidazol-2-yl)picolinamide), have been synthesized. All Ru(II) complexes have been characterized by using various spectroscopic techniques (FTIR, UV–Visible, 1H, 13C, 31P NMR and ESI-MS), conductivity and elemental analyses. The solid-state structures of all Ru(II) complexes, except 2, were substantiated by the single crystal X-ray diffraction technique that revealed versatile coordination modes of two bidentate ligands varying between N–N and N–O modes. All Ru(II) complexes exhibited a distorted octahedral geometry with a bidentate ligand while other coordination sites are occupied by either anionic Cl? or neutral co-ligands (CO, PPh3, CH3CN or (CH3)2SO). These well-defined ruthenium(II) complexes have been utilized as the homogeneous catalysts for the alkylation of amines using alcohols ensuing hydrogen borrowing strategy. Out of six complexes, 1 and 2 were found highly effective catalysts towards the N-alkylation of different amines with assorted alcohols. The alkylated products were obtained in excellent yields with good tolerance to a large variety of functional groups. To evaluate the role of putative Ru-hydride species as the intermediate during the catalytic cycle, the respective Ru-H complexes (7 and 8) were synthesized by the reaction of complexes 1 and 2 with NaBH4. Both Ru-H complexes were characterized using different spectroscopic techniques and crystallography. Importantly, both Ru-H complexes, 7 and 8, were directly able to alkylate imine using alcohol thus confirming the involvement of Ru-hydride species as the intermediates during the proposed catalytic cycle.
Selective C-C bonds formation, N-alkylation and benzo[d]imidazoles synthesis by a recyclable zinc composite
Zhu, Guanxin,Duan, Zheng-Chao,Zhu, Haiyan,Ye, Dongdong,Wang, Dawei
supporting information, p. 266 - 270 (2021/08/06)
Earth abundant metals are much less expensive, promising, valuable metals and could be served as catalysts for the borrowing hydrogen reaction, dehydrogenation and heterocycles synthesis, instead of noble metals. The uniformly dispersed zinc composites were designed, synthesized and carefully characterized by means of XPS, EDS, TEM and XRD. The resulting zinc composite showed good catalytic activity for the N-alkylation of amines with amines, ketones with alcohols in water under base-free conditions, while unsaturated carbonyl compounds could also be synthesized by tuning the reaction conditions. Importantly, it was the first time to realize the synthesis of 2-aryl-1H-benzo[d]imidazole derivatives by using this zinc composite under green conditions. Meanwhile, this zinc catalyst could be easily recovered and reused for at least five times.
Cu-Catalyzed Intermolecular-Site C-H Amination of Cyclohexenone Derivatives: The Benefit of Bifunctional Ligands
Chen, Zi-Sheng,Ji, Kegong,Yang, Fang,Zhao, Xin,Zhou, Qian-Qian,Zou, Shao-Yu
, p. 1732 - 1741 (2022/01/28)
Utilizing 1,10-phenanthroline-Type bifunctional ligands, an efficient Cu-catalyzed intermolecular site-selective remote C-H amination using cyclohexenone derivatives and anilines was realized. The amide group installed on the bifunctional ligand played a
