- 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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- 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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- 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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- 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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- 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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- 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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- 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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- Synthesis and in vitro cytotoxicity of aminocoumarin platinum(II) complexes
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A number of cis-dichloro[bis(aminocoumarin)platinum(II) complexes have been synthesized and evaluated for their in vitro cytotoxicity against Caco-2T cells. The complex with 7-amino-4-trifluoromethylcoumarin as ligand has been found to be the most active (IC50 10 μ/ml) in this study.
- Kokotos, George,Theodorou, Vassiliki,Tzougraki, Chryssa,Deforce, Dieter L.D.,Van Den Eeckhout, Elfreide G.
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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.
- Jin, Yan,Ding, Yin-hao,Dong, Jing-jing,Wei, Yan,Hao, Shuang-hong,Feng, Bai-cheng
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p. 798 - 804
(2020/08/19)
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- 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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- Coumarin-Thiourea Hybrids Show Potent Carbonic Anhydrase IX and XIII Inhibitory Action
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A series of coumarin-thiourea hybrids (4 a–o) has been synthesized, and the compounds have been evaluated against the tumour associated transmembrane isoform, human (h) carbonic anhydrase (CA) hCA IX and the less-explored cytosolic isoform, hCA XIII. All
- Thacker, Pavitra S.,Srikanth, Danaboina,Angeli, Andrea,Singh, Priti,Chinchilli, Krishna Kartheek,Arifuddin, Mohammed,Supuran, Claudiu T.
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p. 1252 - 1256
(2021/02/16)
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- Synthesis and biological evaluation of coumarin-linked 4-anilinomethyl-1,2,3-triazoles as potent inhibitors of carbonic anhydrases ix and xiii involved in tumorigenesis
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A series of coumarin-linked 4-anilinomethyl-1,2,3-triazoles (6a–t) was synthesized via a molecular hybridization approach, through carbon C-6 of the coumarin moiety. The synthesized compounds were evaluated for their inhibition of carbonic anhydrase (CA)
- Thacker, Pavitra S.,Tiwari, Prerna L.,Angeli, Andrea,Srikanth, Danaboina,Swain, Baijayantimala,Arifuddin, Mohammed,Supuran, Claudiu T.
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- Coumarin compound as well as preparation method and application thereof and pharmaceutical composition
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The invention provides a coumarin compound, a preparation method and an application thereof, and a pharmaceutical composition, and belongs to the technical field of medicines. The coumarin compound provided by the invention has high affinity and high sele
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Paragraph 0119-0124
(2021/03/30)
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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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- New coumarin/sulfocoumarin linked phenylacrylamides as selective transmembrane carbonic anhydrase inhibitors: Synthesis and in-vitro biological evaluation
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Two novel series of phenylacrylamide linked coumarins and sulfocoumarins (6a-p, 8a-i, and 14a-g) were synthesized and evaluated against four physiologically relevant human carbonic anhydrases (hCAs, EC 4.2.1.1), isoforms hCA I, hCA II, hCA IX and hCA XII for their inhibitory action. All new compounds when screened for carbonic anhydrase inhibitory activity have shown selective inhibition towards the tumor associated isoforms hCA IX and XII over CA I and II, with inhibition constants in the submicromolar to low nanomolar range. Compound 6b and 14g exhibited significant inhibition with low nanomolar potency against hCA IX, whereas 6k was effective against hCA XII. Compounds 6b, 14g and 6k may be considered as lead molecules for future development of cancer therapeutics based on a novel mechanism of action.
- Angeli, Andrea,Arifuddin, Mohammed,Singh, Priti,Supuran, Claudiu T.,Swain, Baijayantimala
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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.
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- Discovery of Small-Molecule Inhibitors of the HSP90-Calcineurin-NFAT Pathway against Glioblastoma
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Glioblastoma (GBM) is among the most common and malignant types of primary brain tumors in adults, with a dismal prognosis. Although alkylating agents such as temozolomide are widely applied as the first-line treatment for GBM, they often cause chemoresis
- Liu, Zhenzhen,Li, Hongli,He, Lian,Xiang, Yu,Tian, Chengsen,Li, Can,Tan, Peng,Jing, Ji,Tian, Yanpin,Du, Lupei,Huang, Yun,Han, Leng,Li, Minyong,Zhou, Yubin
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p. 352 - 7,365
(2019/03/19)
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- Cobalt-based nanoparticles prepared from MOF-carbon templates as efficient hydrogenation catalysts
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The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Sohail, Manzar,Alshammari, Ahmad S.,Pohl, Marga-Martina,Beller, Matthias,Jagadeesh, Rajenahally V.
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p. 8553 - 8560
(2018/11/30)
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- Heterogeneous Iron-Catalyzed Hydrogenation of Nitroarenes under Water-Gas Shift Reaction Conditions
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Reduction of various nitroarenes in the presence of heterogeneous iron oxide-based catalyst Fe 2 O 3 /NGr@C under water-gas shift reaction (WGSR) conditions has been demonstrated. The catalytic material is prepared in a straightforward manner via deposition/pyrolysis of iron-phenanthroline complex on carbon support. It shows high chemoselectivity towards the reduction of nitroarenes in the presence of other reducible and/or poisoning-capable functional groups. Hydrogenation is achieved using CO/H 2 O as a hydrogen source. Furthermore, it is demonstrated that the presence of triethylamine additive has a significant positive effect on the rate of reduction.
- Ryabchuk, Pavel,Junge, Kathrin,Beller, Matthias
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supporting information
p. 4369 - 4376
(2018/11/21)
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- Preparation method of 6-hydroxy coumarin
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The invention discloses a preparation method of 6-hydroxy coumarin. The preparation method comprises the following steps of: by taking 6-nitryl coumarin as an initial raw material, preparing 6-amino coumarin through reduction; and then preparing 6-hydroxy
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Paragraph 0008; 0025; 0026; 0027; 0028; 0029; 0030
(2017/08/31)
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- Sulfocoumarin-, Coumarin-, 4-Sulfamoylphenyl-Bearing Indazole-3-carboxamide Hybrids: Synthesis and Selective Inhibition of Tumor-Associated Carbonic Anhydrase Isozymes IX and XII
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A series of sulfocoumarin-, coumarin-, and 4-sulfamoylphenyl-bearing indazole-3-carboxamide hybrids were synthesized and investigated as inhibitors of the human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms I and II (cytosolic isozymes), as well as hCA IX and XII (transmembrane, tumor-associated enzymes). Compounds 6 a–g (amide derivatives) and 7 a–h (triazoles) act as “prodrugs”, and their hydrolysis products are the de facto CA inhibitors. These compounds displayed sub-micromolar to high-nanomolar inhibitory activity against hCA isoforms IX and XII, which were recently validated as antitumor drug targets. Moreover, no inhibition of the off-target hCA I and II isoforms was observed. Compounds 8 a–f (another set of triazoles) exhibited nanomolar inhibition against hCA isoforms I, II, IX and XII, among which compounds 8 c, 8 d, and 8 f were found to inhibit the tumor-associated hypoxia-induced hCA isoform IX with Ki values of 1.8, 2.3, and 2.0 nm respectively. Further exploration of these compounds could be useful for the development of novel antitumor agents with selective mechanisms of CA inhibitory action.
- Angapelly, Srinivas,Sri Ramya,Angeli, Andrea,Supuran, Claudiu T.,Arifuddin, Mohammed
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p. 1578 - 1584
(2017/10/16)
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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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- Ni@Pd core-shell nanoparticles supported on a metal-organic framework as highly efficient catalysts for nitroarenes reduction
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Ni@Pd core-shell nanoparticles with a mean particle size of 8-9 nm were prepared by solvothermal reduction of bivalent nickel and palladium in oleylamine and trioctylphosphine. Subsequently, the first-ever deposition of Ni@Pd core-shell nanoparticles having different compositions on a metal-organic framework (MIL-101) was accomplished by wet impregnation in n-hexane. The Ni@Pd/MIL-101 materials were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy and also investigated as catalysts for the hydrogenation of nitrobenzene under mild reaction conditions. At 30 °C and 0.1 MPa of H2 pressure, the Ni@Pd/MIL-101 gives a TOF as high as 375 h-1 for the hydrogenation of nitrobenzene and is applicable to a wide range of substituted nitroarenes. The exceptional performance of this catalyst is believed to result from the significant Ni-Pd interaction in the core-shell structure, together with promotion of the conversions of aromatics by uncoordinated Lewis acidic Cr sites on the MIL-101 support.
- Jian, Siping,Li, Yingwei
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- Chemoselective hydrogenation of functionalized nitroarenes using MOF-derived co-based catalysts
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The synthesis, characterization, and application of nitrogen-doped carbon supported Co catalysts in selective hydrogenation of nitroarenes are described. The cobalt-based catalysts are prepared by simple pyrolysis of ZIF-67, a typical MOF material, under inert atmosphere. Physicochemical properties of the Co/C-N catalysts have been investigated by X-ray diffraction, elemental analysis, atomic absorption spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The Co-based materials were found to be highly efficient in the chemoselective hydrogenation of nitroarenes. A broad range of substituted nitroarenes are converted to the corresponding anilines in excellent yields under industrially viable conditions with other reducing groups remaining intact. In situ ATR-IR and XPS characterizations reveal that the Co-N centers present in the catalyst favor the preferential adsorption of nitro groups, leading to this unique chemoselectivity. The kinetic parameters of 4-nitrostyrene hydrogenation over the Co/C-N catalyst were investigated.
- Wang, Xi,Li, Yingwei
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- Nitrogen-doped graphene-activated iron-oxide-based nanocatalysts for selective transfer hydrogenation of nitroarenes
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Nanoscaled iron oxides on carbon were modified with nitrogen-doped graphene (NGr) and found to be excellent catalysts for the chemoselective transfer hydrogenation of nitroarenes to anilines. Under standard reaction conditions, a variety of functionalized and structurally diverse anilines, which serve as key building blocks and central intermediates for fine and bulk chemicals, were synthesized in good to excellent yields.
- Jagadeesh, Rajenahally V.,Natte, Kishore,Junge, Henrik,Beller, Matthias
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p. 1526 - 1529
(2015/03/14)
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- USE OF THERMALLY-TREATED SUPPORTED COBALT CATALYSTS COMPRISING A POLYCYCLIC AROMATIC STRUCTURE CONSISTING OF NITROGEN LIGANDS FOR HYROGENATING AROMATIC NITRO COMPOUNDS
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The invention relates to the use of thermally-treated supported cobalt catalysts for hydrogenating aromatic nitro compounds, the cobalt catalysts having been prepared by in situ immobilization of a cobalt-amine complex on an inorganic porous support and subsequent pyrolysis, and, in the cobalt-amine complex used, cobalt being present bonded to an aromatic or heterocyclic nitrogen ligand L, the nitrogen ligand being selected so as to form a polyaromatic structure with the cobalt atom.
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Paragraph 0034; 0035
(2015/11/16)
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- Metal-free C(3)-H arylation of coumarins promoted by catalytic amounts of 5,10,15,20-tetrakis(4-diethylaminophenyl)porphyrin
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The metal-free C-H arylation of coumarins was achieved in the presence of catalytic amounts of 5,10,15,20-tetrakis(4-diethylaminophenyl)porphyrin. This mild and environmentally friendly Meerwein arylation provided facile access to a broad variety of 3-arylcoumarins in synthetically useful yields.
- Kojima, Masahiro,Oisaki, Kounosuke,Kanai, Motomu
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supporting information
p. 9718 - 9721
(2016/01/09)
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- Reduction of nitroarenes using CO and H2O in the presence of a nanostructured cobalt oxide/Nitrogen-Doped Graphene (NGr) catalyst
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The most common route to anilines is based on the reduction of the corresponding nitroarenes. In general, hydrogen is preferred as reducing agent and numerous catalytic systems are known to achieve such transformations. Besides, the use of CO/H2O as hydrogen source offers interesting possibilities for reductions. Carbon monoxide is a cheap and abundant chemical used on industrial scale for a variety of transformations. Although the reduction of nitroarenes with CO/H2O is known in the presence of noble-metal catalysts, earth-abundant inexpensive catalysts showing high selectivity have not yet been developed. In this respect, herein we present the use of a heterogeneous cobalt oxide catalyst (Co3O4/NGr@C), which is modified by nitrogen-doped graphene layers. Using this non-noble metal catalyst nitroarenes are reduced in high yields and good chemoselectivities.
- Westerhaus, Felix A.,Sorribes, Ivn,Wienh?fer, Gerrit,Junge, Kathrin,Beller, Matthias
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supporting information
p. 313 - 317
(2015/03/05)
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- Highly selective transfer hydrogenation of functionalised nitroarenes using cobalt-based nanocatalysts
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Anilines are important feedstock for the synthesis of a variety of chemicals such as dyes, pigments, pharmaceuticals and agrochemicals. The chemoselective catalytic reduction of nitro compounds represents the most important and prevalent process for the manufacture of functionalized anilines. Consequently, the development of selective catalysts for the reduction of nitro compounds in the presence of other reducible groups is a major challenge and is crucial. In this regard, herein we show that the cobalt oxide (Co3O4-NGr@C) based nano-materials, prepared by the pyrolysis of cobalt-phenanthroline complexes on carbon constitute highly selective catalysts for the transfer hydrogenation of nitroarenes to anilines using formic acid as a hydrogen source. Applying these catalysts, a series of structurally diverse and functionalized nitroarenes have been reduced to anilines with unprecedented chemo-selectivity tolerating halides, olefins, aldehyde, ketone, ester, amide and nitrile functionalities.
- Jagadeesh, Rajenahally V.,Banerjee, Debasis,Arockiam, Percia Beatrice,Junge, Henrik,Junge, Kathrin,Pohl, Marga-Martina,Radnik, J?rg,Brückner, Angelika,Beller, Matthias
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supporting information
p. 898 - 902
(2015/03/04)
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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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p. 6608 - 6612
(2014/06/09)
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- Copper(I)/silver(I)-phosphine-N-{(2-pyridyl)methyliden}-6-coumarin complexes: Syntheses, structures, redox interconversion, photophysical properties and DFT computation
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Mixed ligand complexes of Cu(I) and Ag(I) with bis(diphenylphosphino) methane (dppm)/1,2-bis(diphenylphosphino)ethane (dppe) and N-{(2-pyridyl) methyliden}-6-coumarin (L) have been synthesized and characterized by elemental analyses, conductivity, 1
- Roy, Suman,Mondal, Tapan Kumar,Mitra, Partha,Sinha, Chittaranjan
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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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- 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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- Efficient and short route for the regioselective synthesis of highly substituted, angularly fused furano-, pyrano-, and pyrrolocoumarin/quinolone derivatives by metal-mediated cyclization
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A one-step efficacious method for the construction of a variety of substituted furano-, pyrano-, and pyrrolocoumarins and pyrroloquinolones in good to excellent yields has been developed. Copyright Taylor & Francis Group, LLC.
- Majumdar,Mondal, Shovan,Chattopadhyay, Buddhadeb
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scheme or table
p. 2147 - 2157
(2010/08/20)
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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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- 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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- Efficient reductions of nitroarenes with SnCl2 in ionic liquid
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Mild, eco-friendly and fast reductions of nitroarenes to aminoarenes have been accomplished using stannous chloride dihydrate in ionic liquid tetrabutylammonium bromide (TBAB) that provides unsolvated nucleophilic bromide ion. Improved yields, lower reaction time, generality, and a less demanding work-up procedure are the notable features of this protocol.
- De, Prithwiraj
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p. 1835 - 1837
(2007/10/03)
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- Studies in 6-benzylideneaminocoumarin: Some observations
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Phthalimidoketene reacts with 6-benzylideneaminocoumarin (2) to give 6-phthalimidoacetylaminocoumarin (6), whereas a mixture of (Z)-4-benzylidene-2-phenyl-5-oxazolone (10) and 6-aminocoumarin (1c) is formed by the interaction of 2-phenyl-5-(4H)-oxazolone (4) and the Schiff base (2).
- Rao, Laxmi,Sanjayan, Gangadhar J.,Mukerjee, Arya K.
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p. 351 - 353
(2007/10/02)
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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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- 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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