23000-33-1Relevant academic research and scientific papers
Dual Role of Oxoaldehydes: Divergent Synthesis of 3-Aryl- and 3-Aroylcoumarins
Moazzam, Ali,Khodadadi, Meysam,Jafarpour, Farnaz,Ghandi, Mehdi
, p. 3630 - 3637 (2022/02/16)
A facile and efficient synthetic approach to various valuable 3-aryl- and 3-aroylcoumarins by the direct arylation and aroylation of coumarins with glyoxals in a metal-free manner is presented. The aryl glyoxal is for the first time recognized to serve as an aryl surrogate in addition to its role as an aroyl transfer reagent via a simple switch in reaction conditions. The approach accommodates a broad substrate scope and high yields of the two types of cross-coupling reactions starting from identical starting materials.
Bulky Selenium Ligand Stabilized Trans-Palladium Dichloride Complexes as Catalyst for Silver-Free Decarboxylative Coupling of Coumarin-3-Carboxylic Acids
Meena, Neha,Kumar, Sunil,Shinde, Vikki N.,Reddy, S. Rajagopala,Himanshi,Bhuvanesh, Nattamai,Kumar, Anil,Joshi, Hemant
supporting information, (2022/01/11)
This report describes the syntheses of three new trans-palladium dichloride complexes of bulky selenium ligands. These complexes possess a Cl?Pd?Cl rotor spoke attached to a Se?Pd?Se axle. The new ligands and palladium complexes (C1?C3) were characterized with the help of NMR, HRMS, UV-Vis., IR, and elemental analysis. The single-crystal structure of metal complex C2 confirmed a square planar geometry of complex with trans-orientation. The X-ray structure revealed intramolecular secondary interactions (SeCH—Cl) between chlorine of PdCl2 and CH2 proton of selenium ligand. Variable-temperature NMR data shows coalescence of diastereotopic protons, which indicates pyramidal inversion of selenium atom at elevated temperature. The relaxed potential energy scan of C2 suggests a rotational barrier of ~12.5 kcal/mol for rotation of chlorine atom through Cl?Pd?Cl rotor. The complex C3 possesses dual intramolecular secondary interactions (OCH2—Cl and SeCH2—Cl) with stator ligand. Molecular rotor C2 was found to be a most efficient catalyst for the decarboxylative Heck-coupling under mild reaction conditions. The protocol is applicable to a broad range of substrates with large functional group tolerance and low catalyst loading (2.5 mol %). The mechanism of decarboxylative Heck-coupling reaction was investigated through experimental and computational studies. Importantly the reaction works under silver-free conditions which reduces the cost of overall protocol. Further, the catalyst also worked for decarboxylative arylation and decarboxylative Suzuki-Miyaura coupling reactions with good yields of the coupled products.
Chlorophyll-catalyzed photochemical regioselective coumarin C-H arylation with diazonium salts
Moazzam, Ali,Jafarpour, Farnaz
supporting information, p. 16692 - 16696 (2020/10/27)
This communication describes the development of a mild method for the cross-coupling of the C3-position of coumarin with an array of diazonium salts mediated by chlorophyll as a biocatalyst via visible light catalysis. A natural pigment such as chlorophyll is used as a green photosensitizer and environmentally benign catalyst. This general and easy procedure provides a transition-metal-free alternative for the formation of 3-aryl coumarin derivatives at room temperature with good to excellent yields. This journal is
Facile one-pot synthetic access to libraries of diversely substituted 3-aryl (Alkyl)-coumarins using ionic liquid (IL) or conventional base/solvent, and an IL-mediated approach to novel coumarin-bearing diaryl-ethynes
Kalkhambkar, Rajesh G.,Laali, Kenneth K.,Malunavar, Shruti S.,Prabhala, Pavankumar,Savanur, Hemantkumar M.,Sutar, Suraj M.
, (2020/04/08)
The in-situ formed carbonylimidazole derivatives of Ar(alkyl)-CH2COOH react at r.t. with substituted salicylaldehydes in [BMIM][PF6] or [BMIM][BF4] as solvent, and [PAIM][NTf2] as basic-IL, to produce libraries of 3-aryl(alkyl)coumarins. Whereas these reactions can also be performed with similar efficiency in THF by employing DBU, the IL approach offers easier work-up and recycling of the IL solvent. An IL-mediated approach to the synthesis of novel coumarin-bearing diaryl-ethynes by the Sonogshira reaction is also reported, and the potential for recycling/reuse of the IL solvent is shown.
Looking for new xanthine oxidase inhibitors: 3-Phenylcoumarins versus 2-phenylbenzofurans
Borges, Fernanda,Delogu, Giovanna L.,Era, Benedetta,Fais, Antonella,Gatto, Gianluca,Kumar, Amit,Matos, Maria J.,Pintus, Francesca,Uriarte, Eugenio
, p. 774 - 780 (2020/07/07)
Overproduction of uric acid in the body leads to hyperuricemia, which is also closely related to gout. Uric acid production can be lowered by xanthine oxidase (XO) inhibitors. Inhibition of XO has also been proposed as a mechanism for improving cardiovascular health. Therefore, the search for new efficient XO inhibitors is an interesting topic in drug discovery. 3-Phenylcoumarins and 2-phenylbenzofurans are privileged scaffolds in medicinal chemistry. Their structural similarity makes them interesting molecules for a comparative study. Methoxy and nitro substituents were introduced in both scaffolds. The current study gives some insights into the synthesis and biological activity of these molecules against this important target. For the best compound of the series, the 3-(4-methoxyphenyl)-6-nitrocoumarin (4), the IC50 value, type of inhibition, cytotoxicity on B16F10 cells and ADME theoretical properties, were determined. Docking studies were also performed in order to better understand the interactions of this molecule with the XO binding pocket. This work is a preliminary screening for further design and synthesis of new non-purinergic derivatives as potential compounds involved in the inflammatory suppression, specially related to gout.
Zn(II)-Catalyzed One-Pot Synthesis of Coumarins from Ynamides and Salicylaldehydes
Yoo, Huen Ji,Youn, So Won
, p. 3422 - 3426 (2019/05/10)
A highly efficient and straightforward synthesis of diversely substituted coumarins from ynamides and salicylaldehydes in the presence of Zn(II) catalyst has been developed. The sulfonamide moiety of ynamides was successfully recycled in this process, serving as an effective traceless directing group for high regioselectivity in the bond-forming event. The advantages of this protocol are good functional group tolerance, broad substrate scope, simple and high-yielding reaction, recovery/reuse of the sulfonamides, low catalyst loading of inexpensive catalyst, and, by these merits, a more cost-effective and greener process.
Decarboxylation of α,β-unsaturated aromatic lactones: Synthesis of: E-ortho -hydroxystilbenes from 3-arylcoumarins or isoaurones
Huang, Xihua,Liu, Jie,Sheng, Jianfei,Song, Xianheng,Du, Zhibo,Li, Mingkang,Zhang, Xuejing,Zou, Yong
supporting information, p. 804 - 808 (2018/03/06)
A simple and environmentally friendly strategy for the synthesis of E-ortho-hydroxystilbenes has been established. Two kinds of α,β-unsaturated aromatic lactones, i.e. the 3-arylcoumarins and the isoaurones, could both readily undergo a cascade hydrolyzation/decarboxylation reaction in the presence of KOH in ethylene glycol to afford the desired E-ortho-hydroxystilbenes in moderate to high yields.
Pd-catalysed carbonylative annulation of salicylaldehydes with benzyl chlorides using N-formylsaccharin as a CO surrogate
Yadav, Vinod K.,Srivastava, Vishnu P.,Yadav, Lal Dhar S.
supporting information, p. 16281 - 16286 (2018/10/04)
A convenient and highly efficient Pd-catalysed carbonylative annulation of salicylaldehydes with benzyl chlorides to afford the corresponding 3-arylcoumarins in good to excellent yields has been developed. Importantly, the protocol utilizes a commercially available, low cost, solid and easy to handle N-formylsaccharin as an alternative to the highly toxic CO gas.
Ph3P/I2-Mediated Synthesis of 3-Aryl-Substituted and 3,4-Disubstituted Coumarins
Phakhodee, Wong,Duangkamol, Chuthamat,Yamano, Dolnapa,Pattarawarapan, Mookda
, p. 825 - 830 (2017/04/06)
Ph3P/I2-Et3N-mediated one-pot two-step esterification-cyclization toward 3-aryl coumarins and 3-aryl-4-methylcoumarins is reported. The reaction of a variety of aryl acetic acids containing steric or reactive group with 2-
Synthesis of 2,2-Difluorinated 4-Isoflavanols/4-Thioisoflavanols via a Base-Catalyzed [4 + 2] Annulation Reaction of gem-Difluoroolefins
Li, Jiaheng,Xu, Cong,Wei, Na,Wang, Mang
, p. 11348 - 11357 (2017/11/10)
DBU-catalyzed sequential intermolecular and intramolecular nucleophilic addition reactions between gem-difluoroolefins and o-hydroxy/mercapto benzaldehydes have been developed to provide a [4 + 2] annulation strategy for facile synthesis of gem-difluorinated isoflavanol derivatives. The competitive addition-elimination reaction of gem-difluoroolefins with nucleophiles was avoided under mild conditions, affording 2,2-difluorinated 4-isoflavanols or 2,2-difluoriated 4-thioisoflavanols in good to excellent yields.
