- Design, synthesis, and antifungal evaluation of novel coumarin-pyrrole hybrids
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A series of coumarin derivatives bearing a pyrrole scaffold were designed, prepared, and assessed for their in vitro antifungal activities against six phytopathogenic fungi. The antifungal activity screening results suggest that some synthesized hybrids exhibited potential fungicidal activities against the tested fungi. In particular, compounds 6j, 6k, 6o, 6p, and 6r displayed significant antifungal effects against Rhizoctorzia solani, and possessed EC50 values of 3.94, 7.75, 6.38, 6.25, and 7.67 μg/ mL, respectively. The above activities are more potent than the commercialized fungicide Boscalid (11.52 μg/mL) and Osthole (9.79 μg/mL). These results provide a significant reference for further rational design of coumarin-based fungicides.
- Zhang, Shuguang,Tan, Xin,Liang, Chaogen,Zhang, Weihua
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p. 450 - 458
(2020/11/30)
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- Polyphosphoric acid-promoted synthesis of coumarins lacking substituents at positions 3 and 4
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Coumarins have recently emerged as a hot topic of research due to their diverse pharmacological properties. This work described a method for the synthesis of 3,4-diunsubstituted coumarins promoted by polyphosphoric acid (PPA) from salicylaldehydes and acetic anhydride. Various coumarins were produced in good to excellent yields.
- Yang, Li-Shou,Wang, Yu,Wang, En-Hua,Yang, Jan,Pan, Xiong,Liao, Xiu,Yang, Xiao-Sheng
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supporting information
p. 1 - 6
(2020/07/25)
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- Synthesis method of coumarin derivatives
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The invention provides a synthesis method of coumarin derivatives. The synthesis method comprises the following steps: adding polyphosphoric acid PPA and a solvent N,N-dimethylformamide DMF, sequentially adding substituted salicylaldehyde and acetic anhydride, and carrying out a heating stirring reaction for 3-6 h under nitrogen protection; and after the reaction is finished, separating and purifying to obtain the coumarin derivative pure products. The synthesis method disclosed by the invention is disclosed for the first time, is short in reaction time, simple to operate, low in catalyst usage amount, cheap, easy to obtain and relatively good in derivative yield, not only provides a new method for synthesizing coumarin derivatives, but also provides more possibilities for large-scale production of products and improvement of production efficiency.
- -
-
Paragraph 0039-0041
(2020/09/23)
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- Design, synthesis and agricultural evaluation of derivatives of N-Acyl-N-(m-fluoro-benzyl)-6-amino-coumarin
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ABTRACT: This study aims to design and synthesize a series of N-Acyl-N-(m-fluoro- benzyl)-6- amino-coumarins through the principle of active substructure stitching, which are based on the core structure of N-(m-fluoro-benzyl)-6-amino-coumarin. The structures of target compounds e1–e25 have been characterized by 1H NMR, 13C NMR, ESI-MS and elemental analysis. Meanwhile, their agricultural activity have been evaluated in two weeds (Amaranth and Crabgrass) and four widespread noxious pathogens (V.mali, B.cinerea, F.axysporium and C.bacteria). The herbicidal activity results showed that almost all synthetic molecules have a greater impact on the stem system than on the root. Excellent inhibition rates were discovered from compounds e2–e5 and e20–e23 against Amaranth on stems, which were above 58percent(20 mg/L), 68percent(100 mg/L) respectively. Compounds e2 and e21 also exhibited striking inhibition on stems growth of both weeds. Anti-pathogenic activity showed that all the compounds exerted a better inhibitory activity on B.cinerea at 20 ppm compared to control carbendazim. All the heterocyclic substituted compounds (e17–e24, >57percent) made a better influence than the control (54.1percent) at the100 ppm. This research provides promising herbicidal and anti-pathogenic agents that have the better effects and can be potential for further development.
- Ding, Yin-hao,Dong, Jing-jing,Feng, Bai-cheng,Hao, Shuang-hong,Jin, Yan,Wei, Yan
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supporting information
(2020/08/19)
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- New copper(I) complex with a coumarin as ligand with antibacterial activity against flavobacterium psychrophilum
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A new copper (I) complex, [Cu(NN1)2](ClO4), was synthesized, where NN1 was a imine ligand 6-((quinolin-2-ylmethylene)amino)-2H-chromen-2-one obtained by a derivatization of natural compound coumarin. The structural characterization in solution was done by NMR techniques, UV-Vis and cyclic voltammetry. The potential antibacterial effect of [Cu(NN1)2](ClO4), was assessed for F. psychrophilum isolated 10094. F. psychrophilum is a Gram-negative bacterium which causes diseases such as bacterial cold-water disease and rainbow trout fry syndrome, causing large economic losses in the freshwater salmonid aquaculture industry. This complex show to have antibacterial activity against F. psychrophilum 10094 at non-cytotoxic concentration in cell line derived from trout (F. psychrophilum 10094 IC50 16.0 ± 0.9; RT-GUT IC50 53.0 ± 3.1 μg/mL).
- Aldabaldetrecu, Maialen,Parra, Mick,Soto, Sarita,Arce, Pablo,Tello, Mario,Guerrero, Juan,Modak, Brenda
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- A Dual Emissive Coumarin–urea Derivative with an Electron-withdrawing Substituent in the Presence of Acetate Anion
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We investigated the fluorescent properties, including the excited-state intermolecular proton transfer, of urea derivatives comprising a coumarin ring, which is a widely used fluorophore. We prepared two different coumarin–urea derivatives, 6CU and 7CU, which bear a urea-based substituent at the 6 and 7 positions of a coumarin ring, respectively. In the presence of the acetate ion, 7CU showed additional tautomer fluorescence emission with respect to 6CU, indicating that tautomer formation depends on the positions of the urea-based substituent on the coumarin ring. Thus, the resonance structures of urea derivatives might play an important role in the behavior of dual fluorescence, which is an important phenomenon applicable to photochemical anion sensing. Moreover, in order to further improve the fluorescence properties of the mentioned derivatives, a CF3 group was introduced in a phenyl ring opposite to a coumarin ring. The fluorescence quantum yield of 7CUCF3 thus synthesized was 65 times as large as that of 7CU, an observation that renders 7CUCF3 a suitable anion sensor candidate. The results of this study will contribute to the development of new molecular designs for highly fluorescent sensing.
- Shinoda, Tomoyuki,Nishimura, Yoshinobu,Arai, Tatsuo
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- Study of the Oxidative Cleavage Proposed in the Biogenesis of Transtaganolides/Basiliolides: Pyran-2-one Aromaticity-Mediated Regioselective Control and Biogenetic Implications
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The synthetic feasibility of the oxidative cleavage: epoxidation of 7-O-geranylscopoletin followed by electrocyclic ring-opening, proposed in the biogenesis of transtaganolides/basiliolides is studied. Unlike the proposed pericyclic reactions, this pathway has not yet been addressed. Three synthetic strategies have been tested consisting of: i) Baeyer–Villiger oxidation of p-quinoids, ii) hydrolysis of quinone monoketals, or iii) direct fragmentation by using oxygen donors. Oxidation of the benzene ring of hydroxylated coumarins has been achieved using peroxyacids, but cleavage took place between undesired positions. The aromaticity conservation of the pyran-2-one cycle during oxidation is the controlling factor of these observed regioselectivities. The use of a 4,5-dihydroxy-2-methoxycinnamate model, in which the pyran-2-one ring does not exert influence on oxidation, has allowed the design of a synthetic sequence toward an analogue of the natural pyran-2-one isolated from Thapsia transtagana, key in the biogenesis. Mechanistic proposals for the obtained results as well as their biogenetic implications are raised.
- álvarez, José María,Jorge, Zacarías D.,Massanet, Guillermo M.
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supporting information
(2020/03/05)
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- Iron-Catalyzed Regioselective Decarboxylative Alkylation of Coumarins and Chromones with Alkyl Diacyl Peroxides
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A facile iron-catalyzed decarboxylative radical coupling of alkyl diacyl peroxides with coumarins or chromones has been developed, affording a highly efficient approach to synthesize a variety of α-alkylated coumarins and β-alkylated chromones. The reaction proceeded smoothly without adding any ligand or additive and provided the corresponding products containing a wide scope of functional groups in moderate to excellent yields. This protocol was highlighted by its high regioselectivity, readily available starting materials, and operational simplicity.
- Jin, Can,Sun, Bin,Xu, Tengwei,Yan, Zhiyang,Zhang, Xun
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supporting information
p. 1585 - 1591
(2019/08/07)
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- Coumarin compound and drug combination and preparation and application methods thereof
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The invention discloses a coumarin compound with BRD (bromodomain-containing protein 4) inhibiting effects. The coumarin compound comprises a compound with a structure shown as the formula (I) and medically acceptable salts thereof. The coumarin compound in a brand-new structure containing coumarin nucleuses can inhibit BRD4 to various degrees and accordingly can be applied to preparing BRD4 inhibitors or to preventing and treating BRD4 activity-related diseases, and due to a huge variety of the related diseases, can be extremely wide in application range. The invention also discloses a preparation method of the coumarin compound. The preparation method of the coumarin compound is rich in material resources, simple in operation, mild in condition, low in cost and highly applicable large-scale industrial production.
- -
-
Paragraph 0053; 0054; 0055
(2019/06/30)
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- Discovery of novel coumarin derivatives as potent and orally bioavailable BRD4 inhibitors based on scaffold hopping
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The bromodomain and extra-terminal (BET) bromodomains, particularly BRD4, have been identified as promising therapeutic targets in the treatment of many human disorders such as cancer, inflammation, obesity, and cardiovascular disease. Recently, the discovery of novel BRD4 inhibitors has garnered substantial interest. Starting from scaffold hopping of the reported compound dihydroquinazolinone (PFI-1), a series of coumarin derivatives were designed and synthesised as a new chemotype of BRD4 inhibitors. Interestingly, the representative compounds 13 exhibited potent BRD4 binding affinity and cell proliferation inhibitory activity, and especially displayed a favourable PK profile with high oral bioavailability (F = 49.38%) and metabolic stability (T1/2 = 4.2 h), meaningfully making it as a promising lead compound for further drug development.
- Zhang, Zhimin,Gu, Lili,Wang, Beibei,Huang, Wenhai,Zhang, Yanmin,Ma, Zhen,Zeng, Shenxin,Shen, Zhengrong
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p. 808 - 817
(2019/03/23)
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- Fabrication of an amyloid fibril-palladium nanocomposite: A sustainable catalyst for C-H activation and the electrooxidation of ethanol
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Amyloids are highly ordered nanofibrils and their tensile strength is similar to that of steel, which makes them resistant to extreme pH and temperature. Based on this rationale, we demonstrate a facile synthesis of palladium, copper, platinum, gold and silver nanocomposites using α-Synuclein (α-Syn) fibrils as a template. We showed that an α-Syn-fibril-palladium nanoparticles (α-Syn-PdNPs) composite can be used as a heterogeneous catalyst in C-H bond activation and the electrooxidation of ethanol. The study demonstrated α-Syn-PdNPs to be a superior heterogeneous catalyst for the synthesis of pharmaceutically valuable benzofuran, naphthofuran, coumarin and N-arylindole via C-H activation. Further, the electrooxidation of ethanol using α-Syn-PdNPs displayed an electrochemically active surface area of 160.6 m2 g-1, which is much higher than the previously reported values for supported Pd nanocomposites.
- Jayarajan, Ramasamy,Kumar, Rakesh,Gupta, Jagriti,Dev, Gayathri,Kadu, Pradeep,Chatterjee, Debdeep,Bahadur, Dhirendra,Maiti, Debabrata,Maji, Samir K.
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supporting information
p. 4486 - 4493
(2019/03/06)
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- Bichromatic Photosynthesis of Coumarins by UV Filter-Enabled Olefin Metathesis
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Herein, we report on a two-step bichromatic synthesis of coumarins involving UV-A and UV-C light. The first step is a UV-A-photoinduced ruthenium-catalyzed cross-metathesis (CM) reaction of 2-nitrobenzyl-protected 2-hydroxystyrenes with acrylates, using an external solution of 1-pyrenecarboxaldehyde as a UV filter. Irradiation in the absence of the filter permanently inhibits the light-activated catalyst due to photocleavage of the photolabile protecting group (PPG) and ensuing phenolate chelation to the ruthenium. The simple removal of the external filter after CM allows further photochemical reactions with UV-C light to achieve more complex architectures, such as the coumarins presented in this work. (Figure presented.).
- Eivgi, Or,Sutar, Revannath L.,Reany, Ofer,Lemcoff, N. Gabriel
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supporting information
p. 2352 - 2357
(2017/07/22)
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- Synthesis, NMR, X-ray and UV/Vis characterization and preliminary luminescence study of some boron β-iminoenolates having 6-aminocoumarin moiety
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Five coumarin-based polarized ethylenes (enaminoketones, enaminoester and enaminoamide) were prepared using the condensation of the parent β-dicarbonyl compounds with 6-aminocoumarin. Reaction of the polarized ethylenes with an appropriate source of trivalent boron gave corresponding boron β-iminoenolates having either BF2 or BPh2 fragment. The prepared iminoenolates were characterized by means of multinuclear magnetic resonance in solution, single-crystal X-ray diffraction and UV/Vis spectroscopy. A preliminary luminescence study of the iminoenolates as well as their parent enamines was done. The compounds exhibited fluorescence in a solid state as well as in a frozen 2-methyltetrahydrofuran at 77 K. Exploratory tests showed promising AIE/AIEE properties of the tested compounds. On the other hand, no fluorescence in a solution state (with one exception) was observed.
- Dou?ová, Hana,?im?nek, Petr,Almonasy, Numan,R??i?ková, Zdeňka
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supporting information
p. 60 - 71
(2015/12/23)
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- Coumarinyl azoimidazolyl complexes of osmium(II) hydridocarbonyls: Spectroscopic and structural characterization, oxidation catalysis, photovoltaic effect and density functional theory computation
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Os(II) hydridocarbonyl complexes of coumarinyl azoimidazoles, [Osh(CO)(PPh3)2(CZ-4R-R′)]0/+ (3, 4) (CZ-R-H = 2-(coumarinyl-6-azo)-4-substituted imidazole or 1-alkyl-2-(coumarinyl-6-azo)-4-substituted imidazole), were characterized from spectroscopic data and the single-crystal X-ray data for one of the complexes, [Osh(CO)(PPh3)2(CZ-4-Ph)] (3c) (CZ-4-Ph = 2-(coumarinyl-6-azo)-4-phenylimidazolate), confirmed the structure. The complexes show higher emission (quantum yield φ = 0.0163-0.16) and longer lifetime (τ = 1.4-10.3 ns) than free ligands (φ = 0.0012-0.0185 and τ = 0.685-1.306 ns). Cyclic voltammetry shows quasi-reversible metal oxidation at 0.67-0.94 V for [Os(III)/Os(II)] and 1.21-1.36 V for [Os(IV)/Os(III)] and subsequent azo reductions (-0.68 to -0.95 V for [-N=N-]/[-NN-]- and irreversible -/[-N=N-]2-) of the chelated coumarinyl azoimidazole. The complexes are photostable and show better photovoltaic power conversion efficiency than free ligands. Also, the complexes were used as catalysts for the oxidation of primary/secondary alcohols to aldehydes/ketones using oxidizing agents like N-methylmorpholine N-oxide, t-BuOOH and H2O2. Density functional theory computation was carried out from the optimized structures and the data obtained were used to interpret the electronic and photovoltaic properties.
- Datta, Papia,Sardar, Dibakar,Panda, Uttam,Halder, Ajanta,Manik, Nabin Baran,Chen, Chun-Jung,Sinha, Chittaranjan
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p. 323 - 334
(2016/05/02)
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- Intramolecular charge transfer in coumarin based donor-acceptor systems: Formation of a new product through planar intermediate
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Fluorescence behavior and intramolecular charge transfer (ICT) property of N,N′-dimethylamino substituted anil derivative of coumarinyl amine was studied by steady state and time-resolved fluorescence spectroscopy in combination with density functional theory calculation. Quantitative analysis of the effect of solvent hydrogen bonding on several spectral parameters was done using multiple regression analysis based on Kamlet-Taft model. The present system shows an additional long wavelength fluorescence band almost instantaneously in presence of methanol in sharp contrast to the model unsubstituted analogue. This new fluorescence band is believed to be due to the formation of a new isomer (cis-type) through a planar intermediate. While there is a substantial barrier (~50 kJ mol-1) in the ground state, the isomerization process in the excited state in polar-protic environment proceeds very fast and believed to be catalyzed by hydrogen bond formation at the imine nitrogen atom in combination with stabilization of the resulting species through ICT.
- Phukan, Smritakshi,Saha, Mithu,Pal, Amarta Kumar,Bhasikuttan,Mitra, Sivaprasad
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- Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates via C-H Bond Activation
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An efficient annulation strategy involving the reaction of phenolic acetates with acrylates in the presence of [Rh2(OAc)4] as catalyst and formic acid as reducing agent, leading to the high yield synthesis of coumarin derivatives, has been developed. The addition of NaOAc as a base increased the yield of the products. The reaction is quite successful for both electron-rich as well as electron-deficient phenolic acetates, affording coumarins with excellent regioselectivity, and proceeds via C-H bond activation proven by deuterium incorporation studies.
- Gadakh, Sunita K.,Dey, Soumen,Sudalai, Arumugam
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p. 11544 - 11550
(2015/12/04)
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- Cp?Co(III)-Catalyzed Annulations of 2-Alkenylphenols with CO: Mild Access to Coumarin Derivatives
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Cp?Co(III)-catalyzed annulations of 2-alkenylphenols with CO for the synthesis of coumarin derivatives have been developed. The reaction features mild reaction conditions, broad substrate scope, and good functional group tolerance. Preliminary mechanistic studies were conducted, suggesting that C-H activation is the turnover limiting step. Furthermore, the efficiency of this reaction was demonstrated by the rapid total synthesis of three natural products herniarin, xanthyletin, and seselin.
- Liu, Xu-Ge,Zhang, Shang-Shi,Jiang, Chun-Yong,Wu, Jia-Qiang,Li, Qingjiang,Wang, Honggen
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supporting information
p. 5404 - 5407
(2015/11/18)
-
- An expeditious coumarin synthesis via a "Pseudocycloaddition" between salicylaldehydes and ketene
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A variety of salicylaldehydes effected tandem nucleophilic addition onto ketene, leading to corresponding coumarins in good yields under mild conditions. This "pseudocycloaddition" represents a very mild variant of the historic Perkin synthesis of coumarin (which remains of key interest in both perfumery and several emerging areas).
- Chandrasekhar, Sosale,Kumar, Honnaiah Vijay
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supporting information
p. 232 - 235
(2015/10/29)
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- An easy route to (hetero)arylboronic acids
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An unprecedented spontaneous reactivity between diazonium salts and diboronic acid has been unveiled, leading to a versatile arylboronic acid synthesis directly from (hetero)arylamines. This fast reaction (35 min overall) tolerates a wide range of functional groups and is carried out under very mild conditions. The radical nature of the reaction mechanism has been investigated.
- Erb, William,Hellal, Akila,Albini, Mathieu,Rouden, Jacques,Blanchet, Jerome
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supporting information
p. 6608 - 6612
(2014/06/09)
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- New series of 6-substituted coumarin derivatives as effective factor Xa inhibitors: Synthesis, in vivo antithrombotic evaluation and molecular docking
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Despite recent progress in antithrombotic therapy, there's still an unmet medical need for safe and orally available anticoagulants. Encouraged by the marked antithrombotic and anticoagulant activities of some coumarin derivatives, twenty-three new N-coumarinyl-4-amidinobenzamides 4a-f and 6-heterocycle substituted coumarin derivatives 5, 6a,b, 10a-e, 12a-e and 14a-d were synthesized and evaluated for their in vivo antithrombotic activity. The most active congeners were the unsubstituted amidine 4a (36.5 s), coumarinyl oxadiazole 5 (42.3 s), bis coumarinyl oxadiazole 6b (37.8 s) and coumarinyl pyrazole 10b (38.5 s) that presented prothrombin time (PT) values comparable to the reference drug warfarin (42.3 s). Furthermore, docking studies were undertaken to gain insight into the possible binding mode of these compounds with the coagulation factor Xa (FXa) binding site.
- Amin, Kamelia M.,Abdel Gawad, Nagwa M.,Abdel Rahman, Doaa E.,El Ashry, Mohamed K.M.
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- Palladium-catalyzed synthesis of benzofurans and coumarins from phenols and olefins
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Triple C-H functionalization: Palladium-catalyzed synthesis of benzofurans and coumarins by reacting phenols and unactivated olefins is described. The reaction comprises sequential C-H functionalization and shows diverse functional group compatibility. Preliminary mechanistic studies shed light into the possible mechanisms. Copyright
- Sharma, Upendra,Naveen, Togati,Maji, Arun,Manna, Srimanta,Maiti, Debabrata
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supporting information
p. 12669 - 12673
(2013/12/04)
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- Amine-catalyzed cascade synthesis of 3,4-diunsubstituted coumarins
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We disclose an efficient route to synthesize 3,4-diunsubstituted coumarins through a cascade organocatalytic reaction. The reaction is catalyzed by using of a combination of benzylamine (10 mol-%) and triethylamine (10 mol-%). Various salicylaldehydes were tested, and the corresponding coumarin products were obtained in good to high yields under mild and metal-free reaction conditions. We disclose an efficient route to synthesize 3,4-diunsubstituted coumarins through a cascade organocatalytic reaction. The reaction is catalyzed by using of a combination of benzylamine (10 mol-%) and triethylamine (10 mol-%). Various salicylaldehydes are tested, and the corresponding coumarin products are obtained in good to high yields under mild and metal-free reaction conditions. Copyright
- Wei, Jia,Wang, Pengcheng,Jia, Qianfa,Huang, Jiaoyao,Du, Zhiyun,Zhang, Kun,Wang, Jian
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supporting information
p. 4499 - 4502
(2013/07/26)
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- Crystal structure and interaction of 6-amino coumarin with nitrite ion for its selective fluorescence detection
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6-Amino coumarin has been established as an efficient nitrite ion selective fluorescent sensor. The developed method shows linearity up to 1.6 × 10-6 molL-1 of nitrite ion concentration. Interference from other common anions is almost negligible. The reagent shows strong binding affinity towards nitrite ion as evident from its binding constant value (5.8 × 104), estimated by Stern-Volmer method. Some real samples were analyzed. Single crystal X-ray structure of the reagent is reported. Preliminary computational studies on the molecular level interaction between the reagent and nitrite ion were performed by density functional theory (DFT, B3LYP) method. Copyright
- Guha, Subarna,Lohar, Sisir,Bolte, Michael,Safin, Damir A.,Das, Debasis
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experimental part
p. 225 - 235
(2012/08/29)
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- Synthesis and biological evaluation of (2,5-dihydro-1H-pyrrol-1-yl)-2H- chromen-2-ones as free radical scavengers
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The allylation of aminocoumarins in the presence of excess of anhydrous K2CO3 and allyl bromide to diallylaminocoumarins is described. The Ring Closing Metathesis reaction of the later with the Grubbs' 1rst generation catalyst under reflux or MW irradiation has resulted mainly to (2,5-dihydro-1H-pyrrol-1-yl)coumarins and (1H-pyrrol-1-yl)coumarins. The new compounds were tested in vitro for their ability: (i) to interact with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) stable free radical, (ii) to inhibit lipid peroxidation, (iii) to scavenge the superoxide anion, (iv) to inhibit the activity of soybean lipoxygenase LO and (v) to scavenge hydroxyl radicals. Most of them were found to be potent lipid peroxidation inhibitors in vitro. The majority of the compounds showed significant hydroxyl radical scavenging activity. Compounds 11a and 12c presenting higher LO inhibitory activity as well as compound 17 were found to present a promising antioxidant and LO inhibitory profile.
- Balabani, Anna,Hadjipavlou-Litina, Dimitra J.,Litinas, Konstantinos E.,Mainou, Maria,Tsironi, Crystal-Catherine,Vronteli, Anastasia
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body text
p. 5894 - 5901
(2012/01/02)
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- Synthesis, structure, spectroscopic properties, electrochemistry, and DFT correlative studies of N-[(2-pyridyl)methyliden]-6-coumarin complexes of Cu(I) and Ag(I)
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6-Aminocoumarin reacts with pyridine-2-carboxaldehyde and has synthesized N-[(2-pyridyl)methyliden]-6-coumarin (L). The ligand, L, reacts with [Cu(MeCN)4]ClO4/AgNO3 to synthesize Cu(I) and Ag(I) complexes of formulae, [Cu(L)2]ClO4 and [Ag(L) 2]NO3, respectively. While similar reaction in the presence of PPh3 has isolated [Cu(L)(PPh3) 2]ClO4 and [Ag(L)(PPh3)2]NO 3. All these compounds are characterized by FTIR, UV-Vis and 1H NMR spectroscopic data. In case of [Cu(L)(PPh3) 2]ClO4 and [Ag(L)(PPh3)2]NO 3, the structures have been confirmed by X-ray crystallography. The structure of the complexes are distorted tetrahedral in which L coordinates in a N,N′ bidentate fashion and other two coordination sites are occupied by PPh3. The ligand and the complexes are fluorescent and the fluorescence quantum yields of [Cu(L)(PPh3)2]ClO 4 and [Ag(L)(PPh3)2]NO3 are higher than [Cu(L)2]ClO4 and [Ag(L)2]NO3. Cu(I) complexes show Cu(II)/Cu(I) quasireversible redox couple while Ag(I) complexes exhibit deposition of Ag(0) on the electrode surface during cyclic voltammetric experiments. gaussian 03 computations of representative complexes have been used to determine the composition and energy of molecular levels. An attempt has been made to explain solution spectra and redox properties of the complexes.
- Roy, Suman,Mondal, Tapan Kumar,Mitra, Partha,Torres, Elena Lopez,Sinha, Chittaranjan
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experimental part
p. 913 - 922
(2011/05/04)
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- Structure, photophysics, electrochemistry, DFT calculation, and in-vitro antioxidant activity of coumarin Schiff base complexes of Group 6 metal carbonyls
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N-[(2-Pyridyl)methyliden]-6-coumarin (L) is synthesized by the condensation of 6-aminocoumarin and pyridine-2-carboxaldehyde. Group-6 tetracarbonyl complexes, [M(CO)4(L)] (M = Cr, Mo, and W) are synthesized and characterized by mass spectrometry and NMR, FT-IR and UV-visible spectroscopy. X-ray crystal structure of [Cr(CO)4(L)] shows N(pyridine), N(imine) chelation to chromium(0). A supramolecular chain is formed by C-H?O and π?π interactions. The ligand and the complexes are fluorescent. Cyclic voltammetry of the complexes exhibit quasireversible M(I)/M(0) redox couple. The complexes exhibit potential antioxidant property both in cell free and in-vitro studies and highest activity is observed to [W(CO)4(L)]. Density functional theory (DFT) computation has been performed to correlate with the electronic configuration, composition of wave functions with the UV-visible spectra and redox properties.
- Datta, Papia,Mukhopadhyay, Ambika Prasad,Manna, Prasenjit,Tiekink, Edward R.T.,Sil, Parames Chandra,Sinha, Chittaranjan
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experimental part
p. 577 - 588
(2012/06/30)
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- Design, synthesis and vasorelaxant evaluation of novel coumarin-pyrimidine hybrids
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The main objective of the present work depends on the hybridization of coumarin moiety as a vasorelaxant scaffold and pyrimidine ring with known potential cardiovascular activity in order to prepare some new potent antihypertensive candidates. Hence, two groups of pyrimidinyl coumarin derivatives were synthesized and evaluated for their vasorelaxing activity. These compounds were prepared via two routes; either preparation of the guanidinocoumarin 4 followed by a cocktail of cyclization reactions to yield a different array of 6-(substituted pyrimidin-2-yl)aminocoumarins 5-17, or through cyclization of the precursor chalcones 22a-g with guanidine hydrochloride to generate the corresponding final compounds, 8-(6-aryl-2-aminopyrimidin-4-yl)-7- methoxycoumarins 23a-g. The effect of these compounds and the coumarin intermediates 3, 4, 21 and 22a-g on nor-epinephrine induced contracture in thoracic rat aortic rings was investigated using prazocin as reference drug. Several derivatives showed promising activities either equal or even better than that of prazocin (IC50 0.487 mM). The most prospective compounds; the pyrimidinylamino coumarin derivatives 8, 17 (IC50 0.411, IC 50 0.421 mM) and the chalcones 22b, 22e (IC50 0.371, 0.374 mM) that displayed the highest activity can be a base for lead optimization and simple but efficient design of new compounds. 2D-QSAR analysis was applied to find a correlation between the experimental vasorelaxant activities of the newly synthesized coumarin derivatives and their different physicochemical parameters. The result of this study showed that the increase in aqueous solubility while retaining good hydrophobic character of the overall molecule is the key for maintaining high relaxation activity.
- Amin, Kamilia M.,Awadalla, Fadi M.,Eissa, Amal A.M.,Abou-Seri, Sahar M.,Hassan, Ghaneya S.
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scheme or table
p. 6087 - 6097
(2011/11/06)
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- A single precatalyst tandem RCM-allylic oxidation sequence
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Ring closing metathesis of allyloxy styrenes and a subsequent Ru-catalyzed allylic oxidation can be combined to a tandem sequence that makes coumarins accessible using less active but more conveniently available first generation catalysts.
- Schmidt, Bernd,Krehl, Stefan
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supporting information; experimental part
p. 5879 - 5881
(2011/06/23)
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- Facile and efficient synthesis of simple coumarins via the Pd(II)/KHC03 catalyzed heck reaction under MW-Assisted neat conditions
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An efficient and fast Pd(II)-catalyzed cross-coupling of aryl halides with olefins has been developed. In the presence of Pd(OAc)2 and PdCI 2 cross-coupling of various aryl halides with olefins underwent smoothly to afford the corresponding products in moderate to high yields under MW mediated neat conditions. Simple coumarins were synthesized in good yields using 2-halophenoles in this procedure. Furthermore no solvent, solid support, expensive or/and toxic ligand is required.
- Valizadeh, Hassan,Vaghefi, Sevil
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experimental part
p. 113 - 120
(2011/06/25)
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- Silver-catalyzed facile decarboxylation of coumarin-3-carboxylic acids
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A simple and highly efficient protocol with mild reaction conditions has been developed that allows the smooth protiodecarboxylation of diversely functionalized coumarin-3-carboxylic acids. In the presence of catalytic amounts of Ag2CO3 and acetic acid, even un-activated coumarin-3-carboxylic acids were converted in good to excellent yields and with great preparative ease to the corresponding coumarin derivatives.
- Jafarpour, Farnaz,Jalalimanesh, Nafiseh,Olia, Mina Barzegar Amiri,Kashani, Asieh Otaredi
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experimental part
p. 9508 - 9511
(2011/01/12)
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- Mild decarboxylative allylation of coumarins
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Allyl esters of 3-carboxylcoumarins undergo facile decarboxylative coupling at just 25-50 °C. This represents the first extension of decarboxylative C-C bond-forming reactions to the coupling of aromatics with sp 3-hybridized electrophiles. Finally, the same concept can be applied to the sp2-sp3 couplings of pyrones and flavones. Thus, a variety of biologically important heteroaromatics can be readily functionalized without the need for strong bases or stoichiometric organometallics that are typically required for more standard cross-coupling reactions.
- Jana, Ranjan,Trivedi, Rushi,Tunge, Jon A.
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supporting information; experimental part
p. 3434 - 3436
(2009/12/01)
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- One-Pot wittig and knoevenagel reactions in ionic liquid as convenient methods for the synthesis of coumarin derivatives
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Efficient synthesis of a variety of 3-substituted coumarins via NaOMe-catalyzed Knoevenagel condensation and one-pot preparation of 3,4-unsubstituted coumarins in the presence of NaOMe via Wittig reaction in room-temperature ionic liquids are described. Knoevenagel condensation of 2-hydroxybenzaldehyde with dimethyl- and diethylmalonate was performed with excellent yields in room-temperature ionic liquids. Although diethyl- and dimethylchloromalonates were mostly recovered unchanged in Knoevenagel condensation, higher conversions were observed via Wittig reaction of these compounds with 2-hydroxybenzaldehyde derivatives and triphenylphosphine. Other 2-hydroxybenzaldehyde derivatives, methyl- and ethylchloroacetates, were reacted in ionic liquids to afford simple coumarins in good yields. These reactions widen the applicability of ionic liquid in organic synthesis. Copyright Taylor & Francis Group, LLC.
- Valizadeh, Hassan,Vaghefi, Sevil
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experimental part
p. 1666 - 1678
(2009/10/02)
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- Task-specific ionic liquid as reagent and reaction medium for the one-pot Horner-Wadsworth-Emmons-type reaction under microwave irradiation
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A task-specific imidazolium-based phosphinite ionic liquid (IL-OPPh2) was used as the dual solvent-reagent for the synthesis of E-cinamates and coumarin derivatives via the one-pot Horner-Wadsworth-Emmons-type reaction. The ionic liquid containing its cor
- Valizadeh, Hassan,Shockravi, Abbas
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experimental part
p. 4341 - 4349
(2010/04/26)
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- Synthesis and preliminary evaluation of some substituted coumarins as anticonvulsant agents
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Some new substituted coumarinylthiazolines, coumarinylthiazolidin-4-ones, and substituted chromenothiazoles were synthesized and evaluated for anticonvulsant activity. Some selected compounds were assayed against seizures induced by pentylenetetrazole (PTZ) and strychnine in mice. Compounds 3b, 6b, and 7b were the most active of the series against PTZ induced seizures. Compound 7b provided anticonvulsant activity (PD50 = 95 mg/kg, ip) at a dose 200 mg/kg compared to phenobarbital (PD50 = 16 mg/kg, ip) at a dose 30 mg/kg (90% protection). No clear correlation was observed between the antiepileptic activity and molecular lipophilicity descriptors of the tested compounds.
- Amin, Kamelia M.,Rahman, Doaa E. Abdel,Al-Eryani, Yasmin A.
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p. 5377 - 5388
(2008/12/20)
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- Simple synthesis of versatile coumarin scaffolds
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We describe an approach using ring-closing metathesis (RCM) to synthesize versatile coumarin derivatives that present appropriate substitutions both at the aromatic and at the α,β-unsaturated lactone ring. The obtained compounds can be used as molecular scaffolds suitable for further diversifications through a combinatorial approach. Copyright Taylor & Francis Group, LLC.
- Polito, Laura,Cravini, Massimiliano,Poletti, Laura,Lay, Luigi
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p. 2203 - 2209
(2007/10/03)
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- Novel method for synthesis of some biologically active aminocoumarins
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Nitration of coumarin 4-methyl acetates using concentrated HNO3 in solvents like chloroform or dichloromethane at lower temperature 'Cheparon effect' was found to occur only on aromatic part of coumarin. Yields of nitrocoumarins are almost quantitative and isomers were separated using column chromatographic technique. Reduction of the nitrocoumarins was carried out in environmentally friendly hydride transfer system using Pd/C as catalyst and formic acid or phosphorous acid as hydride generating reagent. Functional groups like -OH, Br, COCH3, -CH2COOH3 and lactone were not interfering in the reduction of nitro group to amino.
- Mashelkar,Audi
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p. 258 - 261
(2008/09/21)
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- Synthesis of analogues of natural coumarins and coumarinolignans
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3-Aryl-4H-coumarins with the 1,3-benzodioxol, 1,4-benzodioxane, and 1,5-benzodioxepane moieties were synthesized by modified methods.
- Ismailova
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p. 292 - 296
(2008/02/02)
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- Microwave-induced in situ Wittig reaction of salicylaldehydes with ethyl chloroacetate and triphenylphosphine in solventless system
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A variety of coumarins was prepared by an in situ Wittig reaction of salicylaldehydes, triphenylphosphine and ethyl chloroacetate using sodium methoxide/molecular sieves (3A) under solvent-free conditions.
- Valizadeh,Shockravi,Heravi,Ghadim, H. Abbasi
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p. 718 - 720
(2007/10/03)
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- A one-pot and convenient synthesis of coumarins in solventless system
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An efficient and facile preparation of simple coumarins via in situ Wittig reaction of salicylaldehydes, triphenylphosphine, and chloroethylacetate supported on MgO in satisfactory yields in solvent-free condition.
- Shockravi, Abbas,Valizadeh, Hassan,Heravi, Majid M.
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p. 501 - 504
(2007/10/03)
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- Convenient synthesis of a simple coumarin from salicylaldehyde and wittig reagent. IV: Improved synthetic method of substituted coumarins
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The reaction of salicylaldehydes (2) with Horner-Wadsworth-Emmons (HWE) or Ando-HWE reagents was attempted to afford intramolecular phosphonate derivatives (6). A new synthetic method for coumarins (1) was achieved by using protected 2.
- Takeuchi, Yasuo,Ueda, Norihiro,Uesugi, Koji,Abe, Hitoshi,Nishioka, Hiromi,Harayama, Takashi
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p. 217 - 224
(2007/10/03)
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- Cerium(IV) ammonium nitrate mediated nitration of coumarins
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A new convenient method of nitration of coumarins using cerium(IV) ammonium nitrate (CAN) has been developed. Higher regioselectivity is observed with CAN and hydrogen peroxide in aqueous medium in comparison with CAN in acetic acid for nitration of 7-hydroxycoumarin, 7-hydroxy-4-methylcoumarin and their derivatives.
- Ganguly,Sukai,De
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p. 301 - 309
(2007/10/03)
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- An efficient large scale synthesis of coumarins by a dealkylative boron- mediated ring closure of 3-(ortho-methoxyaryl)propenoic esters
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Various substituted coumarins 3 were prepared via a dealkylative boron- mediated ring closure of ortho-methoxycinnamates 2.
- Dubuffet,Loutz,Lavielle
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p. 929 - 936
(2007/10/03)
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- Synthesis of Coumarins by Flash Vacuum Pyrolysis of 3-(2-Hydroxyaryl)propenoic Esters
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Flash vacuum pyrolysis of 3-(2-hydroxyaryl)propenoic esters gives coumarins (and other fused α-pyrones) in high yieid.
- Cartwright, Gary A.,McNab, Hamish
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p. 296 - 297
(2007/10/03)
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- 6-Coumarin diazonium salt: A specific affinity label of the Torpedo acetylcholinesterase peripheral site
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A 6-coumarin diazonium salt was synthesized and tested on Torpedo acetylcholinesterase as a site-directed irreversible probe for quaternary ammonium binding. The rate of the inactivation was examined as a function of time, inhibitor concentration, and pH, which allowed the determination of the dissociation and the rate constants of this efficient affinity labeling process. Protection experiments using tetramethylammonium, edrophonium, and propidium demonstrated that the labeling reaction occurred exclusively at the peripheral quaternary ammonium binding site of the enzyme. This result was confirmed by the modification of propidium binding at the peripheral site after inactivation reaction, as directly determined by fluorescence. Mutations of the likely labeled amino acid residues, Tyr70 and Tyr121, by histidine and phenylalanine indicated a predominant involvement of Tyr70 over Tyr121 in the coupling reaction.
- Schalk, Isabelle,Ehret-Sabatier, Laurence,Feuvre, Yves Le,Bon, Suzanne,Massoulie, Jean,Goeldner, Maurice
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p. 1063 - 1067
(2007/10/03)
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- CONVENIENT SYNTHESIS OF A SIMPLE COUMARIN FROM SALICYLALDEHYDE AND WITTIG REAGENT (III): SYNTHESIS OF NITROCOUMARINS
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Reaction of nitrosalicylaldehydes (1) with carbethoxymethylenetriphenylphosphorane in Et2NPh, in Ph2O, and in the absence of solvent (neat) at 210-215 deg C was investigated.Reaction of 3-nitrosalicylaldehyde (1d) in Et2NPh afforded the benzoxazole (6) and the aminocoumarin (3e) along with the expected coumarin (3d).It was clarified that the origin of carbon-unit introduced for the formation of the benzoxazole ring came from the alkyl group of solvent.
- Harayama, Takashi,Nakatsuka, Kazumitsu,Nishioka, Hiromi,Maurakami, Kyoko,Ohmori, Yukiko,et al.
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p. 2729 - 2738
(2007/10/02)
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- Template-directed photoligation
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Methods, apparatus and compositions are presented for ligating ligands together which bind to a common target. One embodiment includes polynucleotide probes having photoreactive functional groups. The probes are capable of assuming substantially contiguous reactive positions on a target polynucleotide placing the photoreactive groups in juxtaposition. Activation of the photoreactive functional groups with radiant energy form a probe reaction product in which the probes are bound to each other.
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