Herein we disclose a mild protocol for the reductive functionalisation of quinolinium and isoquinolinium salts. The reaction proceeds under transition-metal-free conditions as well as under rhodium catalysis with very low catalyst loadings (0.01 mol %) and uses inexpensive formic acid as the terminal reductant. A wide range of electrophiles, including enones, imides, unsaturated esters and sulfones, β-nitro styrenes and aldehydes are intercepted by the in situ formed enamine species forming a large variety of substituted tetrahydro(iso)quinolines. Electrophiles are incorporated at the C-3 and C-4 position for quinolines and isoquinolines respectively, providing access to substitution patterns which are not favoured in electrophilic or nucleophilic aromatic substitution. Finally, this reactivity was exploited to facilitate three types of annulation reactions, giving rise to complex polycyclic products of a formal [3+3] or [4+2] cycloaddition.
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http://dx.doi.org/10.1002/anie.202204682 | DOI Listing |
Nat Commun
January 2025
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, China.
(Hetero)polyaryl amines are extensively prevalent in pharmaceuticals, fine chemicals, and materials but the intricate and varied nature of their structures severely restricts their synthesis. Here, we present a selective multicomponent cycloaromatization of structurally and functionally diverse amine substrates for the general and modular synthesis of (hetero)polyaryl amines through copper(I)-catalysis. This strategy directly constructs a remarkable range of amino group-functionalized (hetero)polyaryl frameworks (194 examples), including naphthalene, binaphthalene, phenanthren, benzothiophene, dibenzothiophene, benzofuran, dibenzofuran, quinoline, isoquinoline, quinazoline, and others, which are challenging or impossible to obtain using alternative methods.
View Article and Find Full Text PDFJ Mol Recognit
January 2025
Biopolymer Modeling and Protein Chemistry Laboratory, Centre for Advanced Studies in Crystallography and Biophysics, University of Madras, Chennai, India.
Bovine serum albumin (BSA) plays a crucial role as a carrier protein in plasma, binding various ligands, including drugs. Understanding the interaction between BSA and saquinavir, an antiretroviral drug, is essential for predicting its pharmacokinetics and pharmacodynamics. We employed spectroscopic approaches, including circular dichroism spectrometry and fluorescence spectroscopy, to investigate the binding of saquinavir to BSA.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
November 2024
College of Pharmacy, Guangxi University of Chinese Medicine Nanning 530200, China.
The plants of Rutaceae, with wide distribution in China, have a long history of medicinal use. They contain a wide variety of alkaloids, which include isoquinolines, quinolines, acridones, carbazoles, and indoles. Pharmacological studies have shown that most of these alkaloids have antitumor, anti-inflammatory, antiviral, antidiabetic and other activities.
View Article and Find Full Text PDFOrg Lett
December 2024
School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea.
The synthesis of (iso)quinoline-indole hybrids by reacting (iso)quinoline -oxides with -alkynylanilines in the presence of a combination of copper(II) catalyst and a bidentate 2,2'-bipyridine ligand is described. The utility of this method was demonstrated through site-selective functionalization of the synthesized products. A plausible reaction pathway for site-selective amination followed by annulative indole formation was elucidated by a series of mechanistic investigations.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
The homogeneous catalytic hydrogenation of benzo-fused heteroarenes generally provides partially hydrogenated products wherein the heteroaryl ring is preferentially reduced, such as quinoline hydrogenation, leading to 1,2,3,4-tetrahydroquinoline. Herein, we report a carbocycle-selective hydrogenation of fused -heteroarenes (quinoline, isoquinoline, quinoxaline, etc.) using the Ru complex of a chiral spiroketal-based diphosphine (SKP) as the catalyst, affording the corresponding 5,6,7,8-tetrahydro products in high chemoselectivities.
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