- Ionic liquid-mediated synthesis of coumarin-3-carboxylic acids via knoevenagel condensation of Meldrum's acid with ortho-hydroxyaryl aldehydes
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A simple, efficient, and green protocol for synthesis of coumarin-3-carboxylic acids is described via Knoevenagel condensation of Meldrum's acid with ortho-hydroxyaryl aldehydes in [Hmim]Tfa ionic liquid, which was found to give better results than other ionic liquids. Furthermore, ionic liquid is easily reused without any appreciable loss in activity. Copyright Taylor & Francis Group, LLC.
- Darvatkar, Nitin B.,Deorukhkar, Amol R.,Bhilare, Sachin V.,Raut, Dilip G.,Salunkhe, Manikrao M.
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- Coumarin-3-carboxylic acid derivatives as potentiators and inhibitors of recombinant and native N-methyl-d-aspartate receptors
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N-Methyl-d-aspartate receptors (NMDARs) are known to be involved in a range of neurological and neurodegenerative disorders and consequently the development of compounds that modulate the function of these receptors has been the subject of intense interest. We have recently reported that 6-bromocoumarin-3-carboxylic acid (UBP608) is a negative allosteric modulator with weak selectivity for GluN2A-containing NMDARs. In the present study, a series of commercially available and newly synthesized coumarin derivatives have been evaluated in a structure-activity relationship (SAR) study as modulators of recombinant NMDAR activity. The main conclusions from this SAR study were that substituents as large as iodo were accommodated at the 6-position and that 6,8-dibromo or 6,8-diiodo substitution of the coumarin ring enhanced the inhibitory activity at NMDARs. These coumarin derivatives are therefore excellent starting points for the development of more potent and GluN2 subunit selective inhibitors, which may have application in the treatment of a range of neurological disorders such as neuropathic pain, epilepsy and depression. Surprisingly, 4-methyl substitution of UBP608 to give UBP714, led to conversion of the inhibitory activity of UBP608 into potentiating activity at recombinant GluN1/GluN2 receptors. UBP714 also enhanced NMDAR mediated field EPSPs in the CA1 region of the hippocampus. UBP714 is therefore a novel template for the development of potent and subunit selective NMDAR potentiators that may have therapeutic applicability in the treatment of patients with cognitive deficits or schizophrenia.
- Irvine, Mark W.,Costa, Blaise M.,Volianskis, Arturas,Fang, Guangyu,Ceolin, Laura,Collingridge, Graham L.,Monaghan, Daniel T.,Jane, David E.
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- Novel synthetic approach for the access of functionalised 4H-chromenes
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A simple, efficient and high-yielding one-pot protocol for the synthesis of novel functionalised 4H-chromenes and chromene carboxylic acids has been developed using multi-component domino coupling reactions of anil-like compounds with 1,3-diketones and indole in the presence of formic acid catalyst under solvent-free conditions. The protocol avoids the use of expensive catalysts, toxic solvents and chromatographic separation.
- Sadeghpour, Mahdieh,Bagheri, Fatemeh
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- A two-photon benzocoumarin-NBD dyad for highly selective and sensitive ratiometric detection of H2S in biological samples
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Hydrogen sulfide (H2S), the third endogenous gas signaling transmitter, plays an important role in the basic signal conduction process of human physiology and pathology. It is critical to monitor the dynamic change of H2S in living organisms. In this article, a two-photon ratiometric fluorescent probe (BCD) based on the benzocoumarin-NBD framework was first designed and synthesized. The probe showed large emission separation (about 115 nm), excellent selectivity, and high sensitivity. Moreover, it could be applied to ratiometric image endogenous H2S biosynthesis in the living cells and zebrafish.
- Chen, Guofeng,Gao, Jingshuo,Guo, Zhenbo,Jia, Xu,Li, Xiaoliu,Wei, Chao,Wei, Lingyu,Yang, Shuhan,Zhang, Pingzhu
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- Synthesis and Luminescent Properties of Eu3+ and Tb3+ Complexes with Coumarin-3-carboxylic Acids
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Abstract: New Eu3+ and Tb3+ complex compounds [Ln(H2O)2L2]Cl?H2O were synthesized on the basis of coumarin-3-carboxylic acid and its derivatives. Composition and structure of the ligands an
- Gromak,Kolokolov,Dotsenko,Aksenov,Aksenova
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p. 685 - 692
(2021/06/02)
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- Sodium ion chemosensor of 3-oxo-3h-benzo[f]chromene-2- -carboxylic acid: An experimental and computational study
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A fluorescence compound with the typical skeleton of benzocoumarin was synthesized and its interaction with various metal ions was evaluated. The synthesis was performed via Knoevenagel condensation whereas identification of the product was accomplished by various spectroscopic techniques. The chemosensor test against representative metal ions was monitored by fluorescence spectrophotometry. A density functional theory calculation (DFT, functional/basis set; M06/6-31G (d, p)) was also performed to clarify the experimental results and to confirm the mechanism of interaction. 3-Oxo-3H-benzo- [f]chromene-2-carboxylic acid 1 was obtained as a yellow solid in 60 % chemical yield. Melting point; 235.6-236.7 ?C and λmax UV/Vis, λem and Stokes shift (MeOH, nm) of 374, 445 and 71 nm, respectively. The structure of the compound was identified based on spectroscopic data and literature comparison. Compound 1 exhibited a chelation quenched fluorescence (CHQF) phenomenon selectively toward the Na+, with a binding stoichiometry (1:2) and LoD and LoQ of 0.14 and 0.48 mg/L, respectively. Based on DFT calculations, compound 1 chelated Na+ through mechanism of oxidative (1:1 equivalent) and reductive (2:1 equivalent) photoinduced electron transfer (PET), correspondingly.
- Abror, Ajar Faflul,Al-Anshori, Jamaludin,Hidayat, Ace Tatang,Hidayat, Ika Wiani,Juliandri, Juliandri,Mayanti, Tri,Rahim, Andi,Yusuf, Muhammad
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p. 971 - 982
(2021/10/27)
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- 3-carboxylic acid and formyl-derived coumarins as photoinitiators in photo-oxidation or photo-reduction processes for photopolymerization upon visible light: Photocomposite synthesis and 3d printing applications
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In this paper, nine organic compounds based on the coumarin scaffold and different substituents were synthesized and used as high-performance photoinitiators for free radical pho-topolymerization (FRP) of meth(acrylate) functions under visible light irradiation using LED at 405 nm. In fact, these compounds showed a very high initiation capacity and very good polymerization profiles (both high rate of polymerization (Rp) and final conversion (FC)) using two and three-component photoinitiating systems based on coum/iodonium salt (0.1%/1% w/w) and coum/iodonium salt/amine (0.1%/1%/1% w/w/w), respectively. To demonstrate the efficiency of the initiation of photopolymerization, several techniques were used to study the photophysical and photochemical properties of coumarins, such as: UV-visible absorption spectroscopy, steady-state photolysis, real-time FTIR, and cyclic voltammetry. On the other hand, these compounds were also tested in direct laser write experiments (3D printing). The synthesis of photocomposites based on glass fiber or carbon fiber using an LED conveyor at 385 nm (0.7 W/cm2 ) was also examined.
- Dumur, Frédéric,Gigmes, Didier,Graff, Bernadette,Hamieh, Tayssir,Lalevée, Jacques,Noirbent, Guillaume,Rahal, Mahmoud,Toufaily, Joumana
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- Zirconium(IV) oxychloride: A simple and efficient catalyst for the synthesis of chromen-2-one derivatives
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The present work explores a highly efficient, environmental friendly, green protocol for the synthesis of chromen-2-one derivatives (3a-m) by the condensation of salicylaldehydes with various active methylene compounds using zirconium (IV) oxychloride as catalyst. This is a convenient and rapid method for Knoevenagel condensation and this methodology offers several advantages including shorter reaction time, milder conditions, inexpensive catalyst, simple operational procedure and allowed to achieve the desired products in excellent yields. The structures of all the synthesized compounds were confirmed by spectral data.
- TASQEERUDDIN,ASIRI, YAHYA I.,SHAHEEN
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p. 2611 - 2616
(2020/10/22)
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- A Primary Amide-Functionalized Heterogeneous Catalyst for the Synthesis of Coumarin-3-carboxylic Acids via a Tandem Reaction
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A crystalline primary amide-based bifunctional heterogeneous catalyst, {[Cd2(2-BPXG)(Fum)2(H2O)2]·2H2O}n (1) (where, 2-BPXG = 2,2′-((1,4-phenylenebis(methylene))bis((pyridin-2-ylmethyl)azanediyl)) diacetamide and Fum = fumarate), has been developed for the one-pot synthesis of a series of potentially biologically active coumarin-3-carboxylic acids at room temperature via a Knoevenagel-intramolecular cyclization tandem reaction. Catalyst 1 is prepared at room temperature from a one-pot self-assembly process in 81% yield and high purity within a few hours and has a ladder-like polymeric architecture based on single-crystal X-ray diffraction. Additional characterization of 1 includes elemental analysis, infrared spectroscopy, thermogravimetric analysis, and powder X-ray diffraction. Based on the optimized conditions, it is determined that 1 is highly efficient (conditions: 2 mol % catalyst, 3 h, and 26-28 °C in methanol) for this reaction. Its recyclability up to five cycles without significant loss of activity and structural integrity is also demonstrated. Using both electron-donating and electron-withdrawing substituents on the salicylaldehyde substrate, seven different derivatives of coumarin-3-carboxylic acid were made. Additionally, the monoamine oxidase (MAO) inhibitor, coumarin-3-phenylcarboxamide, has also been synthesized from coumarin-3-carboxylic acid obtained in the catalysis process. A detailed mechanism of action is also provided.
- Khullar, Sadhika,Mandal, Sanjay K.,Markad, Datta
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- Fluorescent probe, preparation method thereof, fluorescent probe test paper, and application of fluorescent probe test paper
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The invention belongs to the technical field of biological mercaptan detection, and particularly relates to a fluorescent probe, a preparation method thereof, a fluorescent probe test paper, and an application of the fluorescent probe test paper. The fluorescent probe can specifically recognize biological mercaptan (Cys, Hcy and GSH), and has the advantages of easiness in preparation, low price, strong specificity, high sensitivity, and suitableness for the physiological pH; and the fluorescent probe test paper prepared by using the fluorescent probe can be used to quantitatively detect biological mercaptan in a urine sample through naked eyes, and has great application values in the fields of biomedicines and the like.
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- Synthesis and antioxidant activity of conjugates of hydroxytyrosol and coumarin
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Antioxidants have been the subject of intense research interest due to their numerous health benefits. In this work, a series of new conjugates of hydroxytyrosol and coumarin were synthesized and evaluated for their free radical scavenging, toxicity and antioxidant mechanism in vitro. The all target compounds 14a–t exhibited better radical scavenging activity than BHT, hydroxytyrosol, and coumarin in both DPPH radical and ABTS+ radical cation scavenging assays. The structure-activity relationships study indicated that the number and position of hydroxyl groups on the coumarin ring were vital to a good antioxidant capacity. Furthermore, the most promising compound 14q showed less toxicity in hemolysis assay and weaker antiproliferative effects than BHT against normal WI-38 and GES cells, and enhanced viability of H2O2-induced HepG2 cells. Additionally, 14q decreased the apoptotic percentage of HepG2 cells, reduced the ROS produce and LDH release, and improved GSH and SOD levels in H2O2-treated HepG2 cells. Lastly, 14q exhibited more stability than hydroxytyrosol in methanol solution. These results revealed that conjugations of hydroxytyrosol and coumarin show better antioxidant capacity, and are the efficacious approach to finding novel potential antioxidant.
- Li, Wen-Bo,Qiao, Xue-Peng,Wang, Zi-Xiao,Wang, Shuai,Chen, Shi-Wu
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- Synthesis and Biological Evaluation of Some Succinimide Hybrid Molecules
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In this study, a new series of succinimide hybrid molecules containing isothiocyanate, coumarin, isatin, and furan moieties was synthesized and screened for α-glucosidase and antioxidant activities. Preliminary results revealed that all molecules showed good α-glucosidase inhibition effectiveness. Antioxidant activities of the hybrid molecules were determined using cupric reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) assays. Also, the radical scavenging activities of the synthesized compounds were assayed by using ABTS?+?and DPPH??methods. The results showed that all compounds exhibited moderated to high scavenging activity.
- Fatih Y?lmaz,Mente?e, Emre,Balta?, Nimet
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p. 575 - 584
(2020/01/21)
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- CuH-Catalyzed Atropoenantioselective Reduction of Bringmann's Lactones via Dynamic Kinetic Resolution
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A CuH-catalyzed atropoenantioselective reduction of Bringmann's lactones via dynamic kinetic resolution has been disclosed. This protocol features a broad substrate scope and good functional group tolerance and allows the rapid assembly of various valuabl
- Hu, Le'An,Zhang, Yao,Chen, Gen-Qiang,Lin, Bi-Jin,Zhang, Qing-Wen,Yin, Qin,Zhang, Xumu
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supporting information
p. 5575 - 5580
(2019/07/08)
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- Atropoenantioselective redox-neutral amination of biaryl compounds through borrowing hydrogen and dynamic kinetic resolution
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We report herein a novel atropoenantioselective redox-neutral amination of biaryl compounds triggered by a cascade of borrowing hydrogen and dynamic kinetic resolution under the cooperative catalysis of a chiral iridium complex and an achiral Br?nsted acid. This protocol features broad substrate scope and good functional-group tolerance, and allows the rapid assembly of axially chiral biaryl compounds in good to high yields and with high to excellent enantioselectivity.
- Zhang, Jianwei,Wang, Jian
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p. 465 - 469
(2017/12/15)
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- Atropoenantioselective Redox-Neutral Amination of Biaryl Compounds through Borrowing Hydrogen and Dynamic Kinetic Resolution
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We report herein a novel atropoenantioselective redox-neutral amination of biaryl compounds triggered by a cascade of borrowing hydrogen and dynamic kinetic resolution under the cooperative catalysis of a chiral iridium complex and an achiral Br?nsted acid. This protocol features broad substrate scope and good functional-group tolerance, and allows the rapid assembly of axially chiral biaryl compounds in good to high yields and with high to excellent enantioselectivity.
- Zhang, Jianwei,Wang, Jian
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p. 465 - 469
(2018/02/21)
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- Ruthenium-Catalyzed Atropoenantioselective Synthesis of Axial Biaryls via Reductive Amination and Dynamic Kinetic Resolution
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The unprecedented ruthenium-catalyzed atropoenantioselective reductive amination of aldehydes with alkylamines via a cascade transfer hydrogenation and dynamic kinetic resolution strategy is described. This protocol features broad substrate scope and good functional group tolerance and allows the rapid assembly of axially chiral biaryls in good to high yields with high to excellent enantioselectivities. In addition, such structural motifs may have potential applications in enantioselective catalysis as chiral ligands or catalysts.
- Guo, Donghui,Zhang, Jianwei,Zhang, Bei,Wang, Jian
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p. 6284 - 6288
(2018/10/05)
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- Peptides N-connected to hydroxycoumarin and cinnamic acid derivatives: Synthesis and fluorescence spectroscopic, antioxidant and antimicrobial properties
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The tripeptide Tyr-Gly-Ser and a series of conjugations to coumarin, cinnamic and gallic acid were synthesized in salt form and their antioxidant and antimicrobial activities were investigated. The N-connecting hydroxycoumarin, cinnamic and gallic acid derivatives to peptides and the use of BBr3 as a demethylating agent for peptides was reported. Their activities were investigated based on the conjugated moiety structures. Studies of their activities showed that conjugated tripeptides 7,8-dihydroxycoumarin-peptide (17), caffeic acid-peptide (22) and gallic acid-peptide (28) were found to be superior to ascorbic acid with respect to their antioxidant activity, and 12, 14, 24, and 25 exhibited the most antimicrobial activity in the series compared to amoxicillin. Additionally, the incredible florescence intensity and brightness of 17 in water and DMSO, compared to other synthesized compounds, qualified this peptide as a suitable probe in the human body.
- Ghalehshahi, Hajar G.,Balalaie, Saeed,Aliahmadi, Atousa
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p. 8831 - 8842
(2018/06/11)
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- Synthesis and characterisation of some new hybrid molecules containing thiophene, triazole and coumarin rings under microwave conditions
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In this work, a new series of N′-([4-amino-5-oxo-3-(thiophen-2-yl)-4,5-dihydro-1H-1,2,4-triazol-1-yl]acetyl)-2-oxo-2H-1-benzopyran-3-carbohydrazides (thiophene–triazole–coumarin hybrid molecules) was synthesised from the reaction of 2-[4-amino-5-oxo-3-(thiophen-2-yl)-4,5-dihydro-1H-1,2,4-triazol-1-yl]acetohydrazide and 3-(1H-benzotriazol-1-ylcarbonyl)-2H-chromen-2-ones by using microwave irradiation and conventional heating procedures and their results were compared. The reaction was performed using a very small amount of organic solvent and without using a catalyst.
- Yilmaz, Fatih
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p. 361 - 365
(2018/08/21)
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- Silver-Mediated Oxidative Decarboxylative Trifluoromethylthiolation of Coumarin-3-carboxylic Acids
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The introduction of trifluoromethylthio groups into organic compounds, in particular heterocycles, is important because of the prevalence of these structures in medicinally and agriculturally relevant molecules. Herein, the silver-mediated oxidative decarboxylative trifluoromethylthiolation of coumarin-3-carboxylic acids is reported. This methodology utilizes existing carboxylic acid functionalities for the direct conversion to CF3S groups and results in a broad scope of 3-trifluoromethylthiolated coumarins, including analogues of natural products, in moderate to excellent yields.
- Li, Minghao,Petersen, Jeffrey L.,Hoover, Jessica M.
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supporting information
p. 638 - 641
(2017/02/10)
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- Uncatalysed Production of Coumarin-3-carboxylic Acids: A Green Approach
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A green contribution in short reaction times with moderate yields to produce coumarin-3-carboxylic acids is offered. Five different modes to activate the reactions (microwave, near-infrared, mechanical milling, and ultrasound) were compared with mantle heating in the presence or absence of ethanol, a green solvent. Near-infrared and microwave irradiations deliver the best yields in contrast to ultrasound and mechanical milling; moreover, these four processes offered shorter reaction times in comparison with the conventional mantle heating method. It is also important to highlight that the obtained molecules were produced without the requirement of a catalyst and two nonconventional energies forms are presented as new processes.
- Martínez, Joel,Sánchez, Lilibeth,Pérez, F. Javier,Carranza, Vladimir,Delgado, Francisco,Reyes, Leonor,Miranda, René
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- Et3N catalyzed cascade reaction of Meldrum’s acid with ortho-hydroxyaryl aldehydes for the synthesis of coumarin-3-carboxylic acids under solvent-less condition
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Abstract: The synthesis of coumarin-3-carboxylic acids in good yields is realized through a triethylamine catalyzed Knoevenagel-intramolecular cyclization tandem reaction of Meldrum’s acid with various ortho-hydroxyaryl aldehydes. This method expands the catalyst library about the synthesis of coumarin-3-carboxylic acids and also has advantages of using much less water as solvent, a cheap and eco-friendly catalyst, clean reaction conditions, simple workup procedure and easy isolation. Graphical Abstract: [Figure not available: see fulltext.]
- Pan, Wan-Yü,Xiao, Yü-Meng,Xiong, Hou-Qing,Lü, Cheng-Wei
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p. 7057 - 7063
(2016/08/25)
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- Synthesis and characterization of two novel biological-based nano organo solid acids with urea moiety and their catalytic applications in the synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol), coumarin-3-carboxylic acid and cinnamic acid derivatives under mild and green conditions
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2-Carbamoylhydrazine-1-sulfonic acid and carbamoylsulfamic acid as novel, mild and biological-based nano organocatalysts with urea moiety were designed, synthesized and fully characterized by FT-IR, 1H NMR, 13C NMR, mass spectrometry, elemental analysis, thermal gravimetric, derivative thermal gravimetric, X-ray diffraction patterns, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy and UV/Vis analysis. The catalytic applications of 2-carbamoylhydrazine-1-sulfonic acid and carbamoylsulfamic acid were studied in the synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol), coumarin-3-carboxylic acid and cinnamic acid derivatives via the condensation reaction between several aromatic aldehydes and 1-phenyl-3-methylpyrazol-5-one (synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols)), the Knoevenagel condensation of Meldrum's acid with salicylaldehyde derivatives (synthesis of coumarin-3-carboxylic acids) and the condensation of Meldrum's acid with aromatic aldehydes (synthesis of cinnamic acids) under mild and solvent-free conditions. In the presented studies, some products were formed and reported for the first time. The described nano organo solid acids have potential in industry.
- Zolfigol, Mohammad Ali,Ayazi-Nasrabadi, Roya,Baghery, Saeed
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p. 71942 - 71954
(2015/09/08)
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- Synthesis, fluorescence properties, and antiproliferative potential of several 3-oxo-3H-benzo[f]chromene-2-carboxylic acid derivatives
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In this study, two series of 3-oxo-3H-benzo[f]chromene-2-carboxylic acid derivatives (compounds 5a-i and 6a-g) were synthesized. Their in vitro proliferation inhibitory activities against the A549 and NCI-H460 human non-small cell lung cancer (NSCLC) cell lines were evaluated. Their photophysical properties were measured. Among these target compounds, 5e exhibited the strongest antiproliferative activity by inducing apoptosis, arresting cell cycle, and elevating intracellular reactive oxygen species (ROS) level, suggesting that it may be a potent antitumor agent. In addition, compound 6g with very low cytotoxicity, demonstrated excellent fluorescence properties, which could be used as an effective fluorescence probe for biological imaging.
- Fu, Xiao-Bo,Wang, Xian-Fu,Chen, Jia-Nian,Wu, De-Wen,Li, Ting,Shen, Xing-Can,Qin, Jiang-Ke
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p. 18565 - 18584
(2015/11/11)
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- Novel fluorescent cephalosporins: Synthesis, antimicrobial activity and photodynamic inactivation of antibiotic resistant bacteria
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Two novel fluorescent cephalosporins, TCA and TBCA, were synthesized and characterized by 1H NMR, 13C NMR, UV-vis, and fluorescence spectroscopies. Biological activity assays demonstrated that TCA inactivated a Klebsiella pneumonia strain that expressed extended-spectrum β-lactamases. Incubation of 6 μM TCA with K. pneumonia cultures resulted in cell death for 84% of the cells after 126 J/cm2 of light irradiation. In vitro, TCA exhibited a MIC = 0.5 μg/mL with Staphylococcus aureus. Kinetic evaluation revealed that TCA and TBCA were substrates for B1 and B3 subclass metallo-β-lactamases. TBCA exhibited stronger binding affinities to the Gram-positive bacterial strains MRSA1, MRSA2, and S. aureus with value of 2.95-6.59 μM per 108 cells/mL.
- Xiao, Jian-Min,Feng, Lei,Zhou, Li-Sheng,Gao, Hui-Zhou,Zhang, Yi-Lin,Yang, Ke-Wu
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p. 150 - 159
(2013/03/13)
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- Novel fluorescent risedronates: Synthesis, photodynamic inactivation and imaging of Bacillus subtilis
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Novel fluorescently-labeled conjugates of risedronate were synthesized using an epoxide linker, enabling conjugation of risedronate via its pyridyl nitrogen with the aromatic succinimidyl esters. The compounds were characterized by using 1H NMR, 13C NMR, 31P NMR, UV-vis and fluorescence emission spectroscopies. Biological activity assays showed that the conjugates 14 and 15 exhibited photodynamic inactivation of Bacillus subtilis (ATCC 6633) with 91% and 47% bacterial lethality at 10 μM upon visible light irradiation, respectively. Both 14 and 15 could be also used for fluorescence imaging of Bacillus subtilis.
- Zhou, Li-Sheng,Yang, Ke-Wu,Feng, Lei,Xiao, Jian-Min,Liu, Cheng-Cheng,Zhang, Yi-Lin,Crowder, Michael W.
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p. 949 - 954
(2013/03/14)
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- Rapid synthesis of novel and known coumarin-3-carboxylic acids using stannous chloride dihydrate under solvent-free conditions
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Various coumarin-3-carboxylic acid (=2-oxo-2H-1-benzopyran-3-carboxylic acid; CcaH) derivatives have been synthesized in good yields using catalytic amounts of SnCl2·2 H2O under solvent-free conditions. This inexpensive, nontoxic, and readily available catalytic system (10 mol-%) efficiently catalyzes the Knoevenagel condensation and intramolecular cyclization of various 2-hydroxybenzaldehydes or acetophenones with Meldrum's acid. High product yields, use of inexpensive and safe catalyst, and solvent-free conditions display both economic and environmental advantages. Copyright
- Karami, Bahador,Farahi, Mahnaz,Khodabakhshi, Saeed
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experimental part
p. 455 - 460
(2012/05/04)
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- Potassium phosphate catalyzed efficient synthesis of 3-carboxycoumarins
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An efficient and rapid synthesis of 3-carboxycoumarins has been expediently accomplished by a reaction of salicylaldehyde with Meldrum's acid using potassium phosphate as an inexpensive catalyst at ambient temperature.
- Undale, Kedar A.,Gaikwad, Dipak S.,Shaikh, Tarannum S.,Desai, Uday V.,Pore, Dattaprasad M.
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experimental part
p. 1039 - 1042
(2012/10/08)
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- COSMETIC OR DERMATOLOGICAL COMPOSITION COMPRISING A POLYMER BEARING JUNCTION GROUPS, AND COSMETIC TREATMENT PROCESS
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The present patent application relates to a cosmetic or dermatological composition comprising, in a cosmetically or dermatologically acceptable medium, a polymer comprising: (a) a polymer backbone that may be obtained by reaction: of a polyol comprising 3 to 6 hydroxyl groups;of a monocarboxylic acid containing 6 to 32 carbon atoms;of a polycarboxylic acid comprising at least two carboxylic groups COOH, and/or of a cyclic anhydride such as a polycarboxylic acid and/or of a lactone comprising at least one carboxylic group COOH; and(b) at least one junction group linked to the said polymer backbone and capable of establishing H bonds with one or more partner junction groups, each pairing of a junction group involving at least three H (hydrogen) bonds. The patent application also concerns a cosmetic treatment process using the said composition.
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- Silica sulfuric acid: A versatile and reusable catalyst for synthesis of coumarin-3-carboxylic acids in a solventless system
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Synthesis of substituted coumarin-3-carboxylic acid via Knoevenagel condensation of meldrum's acid with ortho-hydroxyaryl aldehydes in solventless system is described.
- Hekmatshoar, Rahim,Rezaei, Akram,Beheshtiha, S. Y. Shirazi
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experimental part
p. 2491 - 2496
(2010/04/03)
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- Synthesis and photoluminescent properties of two novel tripodal compounds containing coumarin moieties
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Two novel tripodal compounds, tris[2-(7-diethylamino-coumarin-3-carboxamide)ethyl]amine (Tren-C1) and tris[2-(benzo[5,6]coumarin-3-carboxamide)ethyl]amine (Tren-C2), were synthesized and characterized. The UV-vis and fluorescence properties of Tren-C1 and Tren-C2 in solutions were investigated. These two compounds exhibited strong blue emission under ultraviolet light excitation. The maximal fluorescence emission occurred at about the level of 10-5 mol/L. The chromophore units in the tripodal compounds shown a little interaction in the ground state, while the interactions in the excited state was notable and which leads to a broad and bathochromic shift of the emission bands.
- Yu, Tianzhi,Zhang, Peng,Zhao, Yuling,Zhang, Hui,Meng, Jing,Fan, Duowang
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scheme or table
p. 168 - 173
(2009/06/20)
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- Syntheses, characterization and fluorescent properties of two triethylene-glycol dicoumarin-3-carboxylates
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Two novel triethylene-glycol dicoumarin-3-carboxylates were synthesized and characterized by element analysis, 1H NMR, FT-IR and UV-vis absorption spectra. The photoluminescent behaviors of triethylene-glycol dibenzo[5,6]coumarin-3-carboxylate doped in PMMA were discussed. These compounds exhibit strong blue emission under ultraviolet light excitation. Compared to coumarin-3-triethylene glycol diester, the absorption and emission spectra of benzo[5,6]coumarin-3-triethylene glycol diester was bathochromically shifted due to the larger conjugation of benzene moiety. These derivatives have potential possible to explore organic electroluminescent materials.
- Zhang, Hui,Yu, Tianzhi,Zhao, Yuling,Fan, Duowang,Qian, Long,Yang, Changhui,Zhang, Kai
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p. 725 - 727
(2008/02/12)
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- Solid state synthesis of substituted coumarin-3-carboxylic acids via the knoevenagel condensation under microwave irradiation
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Synthesis of substituted coumarin-3-carboxylic acids using the Knovenagel reaction of malonic acid and O-hydroxyaryl aldehydes supported onto HZSM-5 zeolite under microwave irradiation is described.
- Heravi, Majid M.,Hekmatshoar, Rahim,Emamgholizadeh, Maryam
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p. 1893 - 1896
(2007/10/03)
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- A convenient synthesis of coumarin-3-carboxylic acids via Knoevenagel condensation of Meldrum's acid with ortho-hydroxyaryl aldehydes or ketones
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Coumarin-3-carboxylic acids were obtained in high yields with excellent purity from ortho-hydroxybenzaldehydes and Meldrum's acid after a 2 h reflux in ethanol. The less reactive ketones were first reacted with alcoholic ammonia to form ketimines, which were then condensed with Meldrum's acid to generate 4-alkylcoumarin-3-carboxylic acids in moderate yields.
- Song, Aimin,Wang, Xiaobing,Lam, Kit S.
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p. 1755 - 1758
(2007/10/03)
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- Solid phase synthesis of substituted coumarin-3-carboxylic acids via the Knoevenagel condensation
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A solid phase synthesis of substituted coumarin-3-carboxylates using the Knoevenagel condensation reaction between ethyl malonate bound to the Wang resin and ortho-hydroxyarylaldehydes is described. The reaction has been shown to proceed cleanly to give the desired products.
- Watson, Brett T.,Christiansen, Gerda E.
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p. 6087 - 6090
(2007/10/03)
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- A Broadly Applicable Synthesis of Fluorescent Condensed α-Pyrones
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In a two step procedure and in usually good yield an α-pyrone ring can be annelated to (enolized) cyclic β-dicarbonyl compounds like 4-hydroxy-2-pyrones, 4-hydroxycoumarins, 4-hydroxy-2-quinolones and more complex malonylheterocycles, but also to β-naphthole. In a first step the combined action of triethyl orthoformate and arylamines upon the dicarbonyl system affords the anilinomethylene derivatives B in usually high yields.B is reacted with an active methylene nitrile (like alkyl cyano-acetates) and one equivalent of a strong base (like sodium methoxide or potassium hydroxide) in a polar aprotic solvent (like dimethylformamide).Subsequent acidification with dilute aqueous acid gives the corresponding α-pyrone D with yields from 18 to 84percent. The reaction sequence is broadly applicable, which is demonstrated by the synthesis of a series of known (3, 7, 16, 31) and novel (10, 19, 22, 25, 28, 34) heterocyclic systems.Most of them exhibit strong fluorescence in the visible with emission maxima between 450 and 510 nm. - Keywords: Enamines; Fluorescence; α-Pyrone, synthesis
- Wolfbeis, Otto S.,Ziegler, Erich,Knierzinger, Andreas,Wipfler, Helmut,Trummer, Iris
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