607-71-6Relevant academic research and scientific papers
A tandem palladium-catalyzed Heck-lactonization through the reaction of ortho-iodophenols with β-substituted acrylates: synthesis of 4,6-substituted coumarins
Fernandes, Talita de A.,Carvalho, Rita de C.C.,Gon?alves, Tatiana M.D.,da Silva, Alcides J.M.,Costa, Paulo R.R.
, p. 3322 - 3325 (2008)
Coumarins were obtained in one pot through a palladium-catalyzed Heck-lactonization reaction involving ortho-iodophenols and methyl crotonate or a Z-enoate derived from d-mannitol. These reactions were investigated under different conditions and palladium sources. In the more interesting cases, coumarins were prepared in water, using triethylamine as base and 1 mol % of PdCl2 as catalyst.
Immobilized ionic liquid on the zeolite: its characterization and catalytic activity in the synthesis of coumarins via Pechmann reaction
Zendehdel, Mojgan,Khaghaninejad, Soheila,Tavakoli, Fatemeh,Ganji, Shiva
, p. 2555 - 2565 (2020)
In this work, in the first step, the 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium chloride ([MTMSPIm]Cl) is immobilized on HY and NaY zeolites as an acidic catalyst. The synthesized catalysts were well characterized by different methods such as FTIR, TGA, XRD, BET, SEM, EDX and ICP. The characterizations of catalysts indeed show the ionic liquid supported on amine-functionalized zeolites. Also, the result shows the micro-/mesoporous structure for catalysts which have been emerged as an important class of catalytic materials. The micro-/mesocatalyst ([MTMSPIm]Cl@zeolite) was used as an acidic catalyst to synthesize coumarins via Pechmann reaction in solvent-free condition. The effect of different factors such as catalyst amount, solvent and time was investigated. Finally, catalyst can be easily separated and reused for the next reactions at least for five runs without any significant changes in yield and structure of the catalyst. Comparison of modified zeolite with [MTMSPIm]Cl shows higher yield and selectivity and mild condition related to other works.
Iridium-catalyzed enantioselective direct vinylogous allylic alkylation of coumarins
Sarkar, Rahul,Mitra, Sankash,Mukherjee, Santanu
, p. 5767 - 5772 (2018)
The first iridium-catalyzed enantioselective vinylogous allylic alkylation of coumarins is presented. Using easily accessible linear allylic carbonates as the allylic electrophile, this reaction installs unfunctionalized allyl groups at the γ-position of
Coumarin derivatives solvent-free synthesis under microwave irradiation over heterogeneous solid catalysts
Bouasla, Souad,Amaro-Gahete, Juan,Esquivel, Dolores,López, M Isabel,Jiménez-Sanchidrián, César,Teguiche, Mabrouk,Romero-Salguero, Francisco J
, (2017)
A suitable methodology of synthesis of coumarin derivatives by Pechmann reaction over heterogeneous solid acid catalysts in a free solvent media under microwave irradiation is described. Resorcinol, phenol and ethyl acetoacetate were selected as model reactants in the Pechmann condensation. The catalytic activity of several materials—Amberlyst-15, zeolite β and sulfonic acid functionalized hybrid silica—in solvent-free microwave-assisted synthesis of the corresponding coumarin derivatives has been investigated in detail. 7-Hydroxy-4-methylcoumarin and 4-methylcoumarin were obtained in 97% and 43% yields, respectively, over Amberlyst-15. This was the most active catalyst in the Pechmann reaction under studied conditions.
Shape-, size-, and functional group-selective binding of small organic guests in a paramagnetic coordination cage
Turega, Simon,Whitehead, Martina,Hall, Benjamin R.,Meijer, Anthony J. H. M.,Hunter, Christopher A.,Ward, Michael D.
, p. 1122 - 1132 (2013)
The host-guest chemistry of the octanuclear cubic coordination cage [Co8L12]16+ (where L is a bridging ligand containing two chelating pyrazolyl-pyridine units connected to a central naphthalene-1,5-diyl spacer via methylene "hinges") has been investigated in detail by 1H NMR spectroscopy. The cage encloses a cavity of volume of ca. 400 A3, which is accessible through 4 A diameter portals in the centers of the cube faces. The paramagnetism of the cage eliminates overlap of NMR signals by dispersing them over a range of ca. 200 ppm, making changes of specific signals easy to observe, and also results in large complexation-induced shifts of bound guests. The cage, in CD3CN solution, acts as a remarkably size-and shape-selective host for small organic guests such as coumarin (K = 78 M-1) and other bicyclic molecules of comparable size and shape such as isoquinoline-N-oxide (K = 2100 M-1). Binding arises from two independent recognition elements, which have been separately quantified. These are (i) a polar component arising from interaction of the H-bond accepting O atom of the guest with a convergent group of CH protons inside the cavity that lie close to a fac tris-chelate metal center and are therefore in a region of high electrostatic potential; and (ii) an additional component arising from the second aromatic ring (aromatic/van der Waals interactions with the interior surface of the cage and/or solvophobic interactions). The strength of the first component varies linearly with the H-bond-accepting ability of the guest; the second component is fixed at approximately 10 kJ mol-1. We have also used 1H-1H exchange spectroscopy (EXSY) experiments to analyze semiquantitatively two distinct dynamic processes, viz. movement of the guest into and out of the cavity and tumbling of the guest inside the host cavity. Depending on the size of the guest and the position of substituents, the rates of these processes can vary substantially, and the rates of processes that afford observable cross-peaks in EXSY spectra (e.g., between free and bound guest in some cases; between different conformers of a specific host·guest complex in others) can be narrowed down to a specific time window. Overall, the paramagnetism of the host cage has allowed an exceptionally detailed analysis of the kinetics and thermodynamics of its host-guest behavior.
Intramolecular Cyclization of ortho-Iodophenyl 3-Butenoate to 4-Methylcoumarin: Catalysis by Palladium Complexes
Catellani, Marta,Chiusoli, Gian Paolo,Fagnola, Maria Chiara,Solari, Giovanna
, p. 5919 - 5922 (1994)
A new palladium-catalyzed synthesis of 4-alkylcoumarins is reported, based on intramolecular arylation of the 3-alkenoic chain of an ortho-iodophenyl ester. - Key Words: coumarin, palladium catalysis, cyclization.
B(C6F5)3-catalyzed synthesis of coumarins via Pechmann condensation under solvent-free conditions
Prajapti, Santosh Kumar,Rao, S. Prakash
, p. 469 - 473 (2021/03/26)
Tris(pentafluorophenyl)borane [B(C6F5)3] catalyzed simple, efficient and environmentally benign protocol has been developed for the Pechmann condensation using variety of phenols and β-ketoesters under solvent-free conditions to afford coumarin derivatives. The present protocol displayed significant advantages such as low catalyst loading, short reaction time, mild reaction conditions, low toxicity, easy work-up, high yields, and compatibility with other functional groups. In addition, it is a convenient, clean, and fast alternative approach for synthesizing variety of coumarin derivatives. Moreover, the applicability of this method towards large-scale synthesis demonstrated its suitability for the industrial application. Graphic abstract: [Figure not available: see fulltext.]
Functionalizing HY zeolite with sulfonic acid, a micro-meso structure reusable catalyst for organic transformations
Tavakoli, Fatemeh,Zendehdel, Mojgan
, (2021/09/16)
A new class of sulfonic acid functionalized HY zeolite (HY-N-SA) catalyst has been prepared and characterized by some method such as XRD, FT-IR, FESEM, TEM, TGA, NH3-TPD and N2 physisorption. The result shows the micro-meso structure for catalyst without ordering in the mesophase. Then, the HY-N-SA micro-meso structure was used as an acidic catalyst to synthesize of coumarins via Pechmann reaction and facile transformation of amines to formamides under solvent-free condition. To consider the effect of acidity and kind and size of porous on the catalyst activity, this catalyst was compared with NaY-N-SA and MCM-N-SA and pure porous material (NaY and MCM-41). The significant advantages of HY-N-SA with respect to other catalysts are short reaction times, high yields, pure products, mild conditions and easy work-up. In addition, we report an original and environmentally friendly solvent-free procedure which reusability of catalyst makes this method nearly green and environmentally friendly.
Nickel-Catalyzed Hydrodeoxygenation of Aryl Sulfamates with Alcohols as Mild Reducing Agents
Matsuo, Kasumi,Kuriyama, Masami,Yamamoto, Kosuke,Demizu, Yosuke,Nishida, Koyo,Onomura, Osamu
, p. 4449 - 4460 (2021/08/25)
The nickel-catalyzed hydrodeoxygenation of aryl sulfamates has been developed with alcohols as mild reductants. A variety of functional groups and heterocycles were tolerated in this reaction system to give the desired products in high yields. In addition, the gram-scale process and stepwise cine-substitution were also achieved with high efficiency.
Coumarins by Direct Annulation: β-Borylacrylates as Ambiphilic C3-Synthons
Wienhold, Max,Molloy, John J.,Daniliuc, Constantin G.,Gilmour, Ryan
supporting information, p. 685 - 689 (2020/11/30)
Modular β-borylacrylates have been validated as programmable, ambiphilic C3-synthons in the cascade annulation of 2-halo-phenol derivatives to generate structurally and electronically diverse coumarins. Key to this [3+3] disconnection is the BPin unit which serves a dual purpose as both a traceless linker for C(sp2)–C(sp2) coupling, and as a chromophore extension to enable inversion of the alkene geometry via selective energy transfer catalysis. Mild isomerisation is a pre-condition to access 3-substituted coumarins and provides a handle for divergence. The method is showcased in the synthesis of representative natural products that contain this venerable chemotype. Facile entry into π-expanded estrone derivatives modified at the A-ring is disclosed to demonstrate the potential of the method in bioassay development or in drug repurposing.
