- TWO NEW NEOFLAVONOIDS AND C-GLYCOSYLFLAVONES FROM PASSIFLORA SERRATODIGITATA
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The aerial parts of Passiflora serratodigitata yielded 5,7-dihydroxy-4-phenylcoumarin, its 7-β-glucoside and the known C-glycosylflavones 2"-xylosylvitexin, 2"-xylosylisovitexin, vitexin, isovitexin, avicenin, and orientin.The known flavone chrysin was also isolated.This is the first report of neoflavonoids in the family Passifloraceae.Key Word Index - Passiflora serratodigitata; Passifloraceae; 5,7-dihydroxy-4-phenylcoumarin (serratin); serratin 7-β-glucoside; C-glycosylflavones.
- Ulubelen, Ayhan,Kerr, Robert R.,Mabry, Tom J.
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Read Online
- Mechanism of biochemical action of substituted 4-methylcoumarins. Part 11: Comparison of the specificities of acetoxy derivatives of 4-methylcoumarin and 4-phenylcoumarin to acetoxycoumarins: Protein transacetylase
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Our earlier observations led to the identification of a microsomal enzyme termed as acetoxy drug: protein transacetylase (TAase) catalyzing the transfer of acetyl groups from acetylated polyphenols to the receptor proteins. TAase was conveniently assayed
- Kumar, Ajit,Singh, Brajendra K.,Tyagi, Rahul,Jain, Sapan K.,Sharma, Sunil K.,Prasad, Ashok K.,Raj, Hanumantharao G.,Rastogi, Ramesh C.,Watterson, Arthur C.,Parmar, Virinder S.
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Read Online
- Synthesis of novel coumarin containing conjugated fluorescent polymers by Suzuki cross-coupling reactions and their chemosensing studies for iron and mercury ions
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Conjugated fluorescent polymers are very useful materials for chemical and biochemical sensors. Herein we report the synthesis of four novel conjugated coumarin-containing fluorescent co-polymers (P1–P4) by palladium catalyzed Suzuki-Miyaura cross-couplin
- Bhaumick, Prabhas,Jana, Asim,Choudhury, Lokman H.
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- Synthesis of C4-substituted coumarins via Pechmann condensation catalyzed by sulfamic acid. Insights into the reaction mechanism by HRMS analysis
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A series of functionalized C4-substituted coumarins were synthesized by exploring the reaction of activated and non-activated phenols and β-ketoesters under solvent-free conditions in the presence of sulfamic acid as a Br?nsted acid catalyst. Fifteen exam
- Barcellos, Thiago,Lenard?o, Eder J.,Moraes, Maiara C.
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p. 151 - 163
(2022/01/28)
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- Compounds for preventing or treating lipid metabolism-related diseases
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The present invention relates to the field of biomedicines, and in particular to a structure capable of binding LC3 and a structure capable of binding a lipid droplet linked together by a covalent linkage, thereby forming a 'LC3 binding moiety - lipid dro
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Paragraph 0576-0578
(2021/10/27)
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- MnSb2O6-chitosan nanocomposite: An efficient catalyst for the synthesis of coumarins via Pechmann reaction
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In this work, MnSb2O6-chitosan nanocomposites were synthesized and have been employed in Pechmann condensation for the synthesis of coumarin derivatives. MnSb2O6-chitosan nanocomposites were characterized by Fou
- Bahramnezhad, Baharak,Ghazanfari, Dadkhoda,Sheikhhosseini, Enayatollah,Akhgar, Mohammad Reza,Ahmadi, Sayed Ali
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supporting information
p. 173 - 181
(2019/11/20)
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- Investigation of HMG-CoA reductase inhibitory and antioxidant effects of various hydroxycoumarin derivatives
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Cardiovascular diseases are one of the primary causes of deaths worldwide, and the development of atherosclerosis is closely related to hypercholesterolemia. As the reduction of the low-density lipoprotein cholesterol level is critical for treating these
- Ozalp, Lalehan,Dan??, ?zkan,Yuce-Dursun, Basak,Demir, Serap,Gündüz, Cihan,Ogan, Ayse
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- Preparation of a novel, efficient, and recyclable magnetic catalyst, γ-Fe2O3@HAp-Ag nanoparticles, and a solvent- and halogen-free protocol for the synthesis of coumarin derivatives
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In this protocol, Ag supported on the hydroxyapatite-core–shell magnetic γ-Fe2O3nanoparticles (γ-Fe2O3@HAp-Ag NPs) as a novel, efficient, and magnetically recyclable catalyst is synthesized, and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). The use of the catalyst is described in the synthesis of coumarin derivatives by the Pechmann condensation of various phenols with β-ketoesters under solvent- and halogen-free conditions at 80?°C. This novel and inexpensive method offers advantages, such as recyclability simple experimental protocol, short reaction time, minimal work-up procedure, and excellent yields of products, together with desirable, eco-friendly, green aspects by avoiding toxic elements and solvents, and ease of recovery from the reaction mixture using an external magnet.
- Abbasi, Zahra,Rezayati, Sobhan,Bagheri, Maryam,Hajinasiri, Rahimeh
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- SnCl4 grafted on silica gel: an efficient catalyst for solvent-free synthesis of coumarins via the Pechmann condensation
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A facile synthesis of substituted coumarins via Pechmann condensation catalyzed by SnCl4 grafted on silica gel is described, which was conducted under solvent-free condition in high yields. The catalyst is noncorrosive and can be easily prepared and separated from the reaction mixture. This methodology offers some advantages with regard to yield of products, simplicity in operation and green aspects.
- Sun, Rui,Gao, Yanjuan,Ma, Ying,Yang, Guangde,Li, Yiping
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p. 737 - 742
(2017/01/17)
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- Neoflavonoids as inhibitors of HIV-1 replication by targeting the Tat and NF-κB pathways
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Twenty-eight neoflavonoids have been prepared and evaluated in vitro against HIV-1. Antiviral activity was assessed on MT-2 cells infected with viral clones carrying the luciferase reporter gene. Inhibition of HIV transcription and Tat function were teste
- Olmedo, Dionisio A.,López-Pérez, José Luis,Del Olmo, Esther,Bedoya, Luis M.,Sancho, Rocío,Alcamí, José,Mu?oz, Eduardo,San Feliciano, Arturo,Gupta, Mahabir P.
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- Nanosilica molybdic acid: synthesis, characterization and application as a green and reusable catalyst for the Pechmann condensation
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Abstract: Nanosilica molybdic acid (SMA NPs) was founded as an efficient and recyclable nanocatalyst for the synthesis of coumarin derivatives in excellent yields with good purity. Nano-SMA as a new solid acid was characterized by X-ray fluorescence, X-ray diffraction, energy-dispersive X-ray analyzer, transmission electron microscopy and Fourier transform infrared spectroscopy. Coumarin derivatives were obtained via the Pechmann condensation reaction of phenols and β-ketoesters at 80?°C under solvent-free conditions. The main advantages of the present procedure are high yields, shorter reaction time and green chemistry procedure, simple work-up and inexpensive and reusability of the catalyst. Graphical Abstract: [Figure not available: see fulltext.]
- Kiani, Mahtab,Karami, Bahador
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p. 655 - 663
(2017/01/17)
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- L-ascorbic acid: A green and competent promoter for solvent-free synthesis of flavones and coumarins under conventional as well as microwave heating
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Background: An expeditious approach has been developed for the synthesis of two distinct classes of benzopyrones viz. flavones and coumarins under solvent-free conditions. L-Ascorbic acid was found to be an effective promoter under microwave irradiation and conventional heating. Various benzo-α-pyrones and benzo-γ-pyrones were synthesized with overall good yields. The present protocol is highly facile and needs no column chromatography for purification and therefore it would serve as an effective and compatible method under both microwave irradiation and conventional heating. Results: The catalytic ability of L-ascorbic acid was investigated for the synthesis of flavones and coumarins. For this purpose, cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanedione and Pechmann coumarin synthesis, reactions were selected. And accordingly, it was observed that one mole of L-ascorbic acid was necessary for the completion of reaction. In all the cases, the desired flavones were smoothly generated with good to excellent yields; indicating its excellent tolerance for various functional groups. However, electron donating groups favors coumarin synthesis under these conditions. All the reaction mixtures were carefully analyzed and NMR indicates high conversions and lack of side products. Conclusion: We have developed L-ascorbic acid-promoted, solvent-free and simple method for the synthesis of benzo-α-pyrones and benzo-γ-pyrone under microwave irradiation as well as conventional heating in good to excellent yields. The notable advantages of this method are solvent-free conditions, inexpensive and efficient eco-friendly promoter, and shorter reaction time and can be carried out under air. This methodology is highly facile and requires no column chromatography for purification. The resulting flavones and coumarins are versatile building blocks in the construction of heterocyclic architectures, dominant in natural products. Further studies of exploiting the efficiency of L-ascorbic acid as a promoter in synthesis of various heterocyclic compounds are in progress.
- Dengale, Rohit Arvind,Thorat, Nitin Madhu,Thopate, Shankar Ramchandra
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p. 734 - 741
(2017/02/05)
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- Natural organic acids promoted green and expeditious synthesis of coumarins under solvent free condition
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Green and highly efficient synthesis of coumarins by Pechmann condensation, using naturally occurring acids under solvent free condition, is described. Various phenols efficiently condensed with ethyl acetoacetate under conventional as well as microwave i
- Rohokale, Sandeep V.,Kote, Santosh R.,Thopate, Shankar R.
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- Meglumine sulfate catalyzed solvent-free one-pot synthesis of coumarins under microwave and thermal conditions
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A convenient method has been developed for the Pechmann reaction of phenols and β-keto esters catalyzed by meglumine sulfate. Solvent-free conditions, inexpensive catalyst, short reaction times, high yield, and ease of purification of the products are the advantages of this protocol. This novel catalytic system is expected to contribute to the development of more benign Pechmann condensation reactions of phenols with β-keto esters.
- Moradi, Leila,Rabiei, Khadijeh,Belali, Fateme
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supporting information
p. 1283 - 1291
(2016/08/16)
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- Agents and methods for treating ischemic and other diseases
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This invention relates to compounds that modulate TRPM7 protein activity and use of the same for treatment or prophylaxis of ischemia, cancer, pain or glaucoma.
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Page/Page column 139; 140
(2016/06/01)
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- Synthesis and NMR of 4-Aryl-3,4-dihydrocoumarins and 4-arylcoumarins
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This paper described the synthesis and 1H and 13C NMR chemical shifts of a series of 4-aryl-3,4-dihydrocoumarin and 4-arylcoumarin derivatives based on a combination of 1H and 13C NMR, HSQC and HMBC experiments.
- Sun, Jie,Wang, Yanfeng
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p. 7753 - 7758
(2015/02/02)
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- Antioxidant and antitumor activities of 4-arylcoumarins and 4-aryl-3,4-dihydrocoumarins
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Five 4-arylcoumarins (1c-g) and twelve 3,4-dihydro-4-arylcoumarins (2a-l) were synthesized and tested for antioxidant activity, antitumor activity, toxicity and structure-activity relationships analysis. 4-Arylcoumarins and 3,4-dihydro-4-arylcoumarins tha
- Zhang, Keyun,Ding, Weixian,Sun, Jie,Zhang, Bin,Lu, Fujiao,Lai, Ren,Zou, Yong,Yedid, Gabriel
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supporting information
p. 203 - 210
(2015/02/19)
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- Synthesis of the coumarins via pechmann method in the presence of environmentally friendly Y(NO3)3×6H2O
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Several substituted coumarins can be prepared in high yield and purity by direct reaction of β-keto esters and phenol derivatives in the presence of a catalytic amount Y(NO3)3×6H2O as Lewis acid and at ambient temperature under solvent-free conditions. Several substituted coumarins can be prepared in high yield and purity by direct reaction of β-keto esters and phenol derivatives in the presence of a catalytic amount Y(NO3)3×6H2O as Lewis acid and at ambient temperature under solvent-free conditions. This method that is based on Pechmann condensation is very easy and rapid reaction for the synthesis of coumarin derivatives. Copyright
- Karami, Bahador,Kiani, Mahtab
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p. 213 - 216
(2014/05/06)
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- An efficient synthesis of new khellactone-type compounds using potassium hydroxide as catalyst via one-pot, three-component reaction
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In the present work, three-component synthesis for novel khellactone-type compounds via the reaction of Meldrum's acid, aryl aldehydes and 5,7-dihydroxy benzopyrone derivatives was described. In this reaction 10-aryl substituted-9,10-dihydropyrano[2,3-h]benzopyrone-8-ones as new khellactone analogous in the presence of catalytic amount of potassium hydroxide as cheap and green basic catalyst were obtained in good to excellent yields under refluxing methanol.
- Karami,Eskandari,Khodabakhshi
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p. 631 - 637
(2014/05/20)
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- Magnesium bis(trifluoromethane)sulfonimide: An efficient catalyst for the synthesis of coumarins under solvent-free conditions
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Magnesium bis(trifluoromethane)sulfonimide [Mg(NTf2) 2] is an efficient catalyst for the synthesis of coumarins via the Pechmann condensation reaction of phenols and β-ketoesters under solvent-free conditions.
- Wang, Hongshe
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p. 411 - 414
(2013/05/21)
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- Ionic-liquid-catalyzed green synthesis of coumarin derivatives under solvent-free conditions
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Broensted acidic ionic liquids, namely 2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium dihydrogen phosphate, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulfate, and triphenyl(propyl-3-sulfonyl)phosphonium toluenesulfonate, catalyzed efficient Pechmann condensation of phloroglucinol with β-keto ethyl/methyl esters. 5,7-Dihydroxy-4-methylcoumarin and 5,7-dihydroxy-4-phenylcoumarin were prepared in good to excellent yields under mild, ambient, and solvent-free conditions. Pyrano[2,3-h]coumarins were then prepared by one-pot three-component reactions of 5,7-dihydroxy-4-subsituted coumarin, malononitrile, and aldehydes in the presence of catalytic amounts of Broensted basic ionic liquids, namely 2-hydroxyethylammonium formate, 3-hydroxypropanaminium acetate, 1-butyl-3-methylimidazolium hydroxide, pyrrolidinium formate, and pyrrolidinium acetate, under thermal solvent-free conditions. The catalysts are environmentally benign and can be easily prepared, stored, and recovered without significant loss of activity.
- Shaterian, Hamid Reza,Aghakhanizadeh, Morteza
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p. 1690 - 1696
(2013/10/21)
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- Synthesis of coumarins and 2,3-dihydroquinazolin-4(1H)-ones using trichloroacetic acid as a catalyst
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Trichloroacetic acid was used as an efficient catalyst for the synthesis of coumarins from phenols and β-ketoesters and in an efficient synthesis of 2,3-dihydroquinazolin-4(H)-ones through the condensation of 2-aminobenzamide with aldehydes or ketones under solvent-free conditions. The remarkable advantages offered by this method are short reaction times, simple procedure, and an easy work-up without using any chromatographic methods.
- Karimi-Jaberi, Zahed,Zarei, Leila
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p. 178 - 183
(2013/06/27)
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- Alternative two-step route to khellactone analogues using silica tungstic acid and sodium hydrogen phosphate
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A series of coumarins was synthesised via the silica tungstic acid-catalysed Pechmann reaction; some of these were employed for known three-component reactions with aromatic aldehydes and malononitrile in the presence of sodium hydrogen phosphate (Na2HPO4) as a basic catalyst, affording a variety of potentially anti-HIV active khellactone analogues.
- Karami, Bahador,Khodabakhshi, Saeed,Eskandari, Khalil
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p. 1474 - 1478
(2013/07/26)
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- An environmentally friendly, chemoselective, and efficient protocol for the preparation of coumarin derivatives by Pechman condensation reaction using new and reusable heterogeneous Lewis acid catalyst polystyrene-supported GaCl 3
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An environmentally benign Pechman protocol for the one-pot synthesis of 4-substituted coumarins through the condensation reactions of phenol substrates with β-ketoesters using polystyrene-supported GaCl3 (PS-GaCl3) as a highly active and reusable solid Lewis acid catalyst under mild and heterogeneous conditions in good to excellent yields is described. This new protocol is easy, simple, cost-effective, chemoselective, and in addition has the advantages of easy availability, stability, reusability and eco-friendly character of the catalyst, high to excellent yields, simple experimental and work-up procedure.
- Rahmatpour, Ali,Mohammadian, Sara
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p. 271 - 278
(2013/05/08)
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- Silica supported boric tri-sulfuric anhydride as a novel and efficient catalyst for solvent-free synthesis of coumarins via Pechmann condensation
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It is found that silica supported boric trisulfuric anhydride (BTSA.SiO2) is a novel, suitable and versatile catalyst for efficient and clean synthesis of coumarins via Pechmann cyclocondensation under mild and solvent-free conditions. Different kinds of
- Parhami, Abolfath,Zare, Abdolkarim,Nikrooz, Marzieh,Khalafi-Nezhad, Ali,Haghighi, Saghar Mowlazadeh,Bargebid, Rahele,Moosavi-Zare, Ahmad Reza
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p. 111 - 121,11
(2020/09/02)
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- One-pot, three component approach to synthesis of multipart fused heterocyclic compounds: Synthesis of fused pyran-2-ones
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An efficient, three-component synthesis of novel class of dihydropyran-2-ones which are fused with coumarin rings, from reaction between Meldrum's acid, aryl aldehydes and 5,7-dihydroxy-4-methyl (and phenyl) coumarin was described. In this research 9,10-dihydropyrano[2,3-h]benzopyrone-8-ones in the presence of catalytic amount of piperidine as organo basic catalyst were obtained in good to excellent yields under refluxing methanol for the time.
- Karami, Bahador,Eskandari, Khalil,Khodabakhshi, Saeed
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p. 76 - 84,9
(2020/09/02)
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- Efficient synthesis and biological evaluation of 4-arylcoumarin derivatives
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Two bioactive natural 4-arylcoumarins, 5,7,4′-trimethoxy-4- phenylcoumarin (1a), 5,7-dimethoxy-4-phenylcoumarin (1b) and five closely related derivatives 1c-g were synthesized. In vitro evaluation with a catechol subunit for antioxidant and antimicrobial activity, these compounds using standard methods showed that compounds 1d, 1f displayed promise radical scavenging activity and 1f was found to be the most active one against Bacillus dysenteriae.
- Sun, Jie,Ding, Wei Xian,Zhang, Ke Yun,Zou, Yong
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scheme or table
p. 667 - 670
(2012/01/13)
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- ZrOCl2.8H2O/SiO2: An efficient and recyclable catalyst for the preparation of coumarin derivatives by Pechmann condensation reaction
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Silica gel supported zirconyl chloride octahydrate was found to be an efficient and recyclable catalyst for the synthesis of a series of biologically important molecules in high turnover numbers and rates. Several substituted coumarins can be prepared in high yield and purity by direct reaction of β-keto esters and phenol derivatives in the presence of a catalytic amount of ZrOCl2.8H2O/SiO2 as Lewis acid and at ambient temperature under solvent-free conditions. This method which is called Pechmann condensation is a very easy and a rapid reaction for the synthesis of coumarin derivatives.
- Karami, Bahador,Kiani, Mahtab
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experimental part
p. 62 - 67
(2012/01/15)
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- Synthesis and evaluation of antibacterial activities of 5,7-dihydroxycoumarin derivatives
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This study examines the synthesis and antibacterial activities of 5,7-dihydroxycoumarin derivatives, whose structures were confirmed using analytical and spectral data. Twenty compounds were tested for their antibacterial activities against five microbial species such as E. coli, S. aureus, K. pneumonia, P. aeruginosa, and S. typhimurium were studied. Compounds 5 and 12 exhibited the most potent activity against Staphylococcus aureus with a MIC value of 2.5 μg/mL for each of the compounds. Copyright
- Chin, Yi-Ping,Huang, Wei-Jan,Hsu, Feng-Lin,Lin, Mei-Hsiang,Lin, Yuh-Ling
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experimental part
p. 386 - 393
(2012/01/11)
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- Synthesis of coumarins and neoflavones through zinc chloride catalyzed hydroarylation of acetylenic esters with phenols
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Acetylenic esters react with oxygenated phenols under solvent-free conditions in the presence of only 5 mol% of zinc chloride as a catalyst to give coumarins and neoflavones in reasonable-to-good yields. Georg Thieme Verlag Stuttgart. New York.
- Leao, Raquel A. C.,Def.demoraes, Paula,Pedro, Marcella C. B. C.,Costa, Paulo R. R.
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experimental part
p. 3692 - 3696
(2011/12/16)
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- Synthesis of 3-amino-4-hydroxy coumarin and dihydroxy-phenyl coumarins as novel anticoagulants
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Natural and synthetic coumarin derivatives have been shown to possess several beneficial pharmacological effects. The anticoagulation and antithrombotic activities of the 4-hydroxy coumarin derivatives are well known. In this study, besides the 4-hydroxy substituent phenyl and p-methylphenyl derivatives were synthesized and confirmed on the basis of their spectral data. 3-Amino-4-hydroxy coumarin, 5,7-dihydroxy-4-phenyl coumarin and 7,8-dihydroxy-3-(4-methylphenyl) coumarin were tested in rats to determine whether they had any effect on vitamin K inhibition by investigating the prothrombin time (PT). PT values of coumarin derivatives were compared with those of warfarin (CAS 81-81-2), which is the most commonly used anticoagulant. 7,8-Dihydroxy-3-(4-methylphenyl)coumarin increased PT when compared to saline treated control group and other coumarins synthesized, 3-amino-4-hydroxy coumarin and 5,7-dihydroxy-4-phenyl coumarin. ECV · Editio Cantor Verlag.
- Danis, Ozkan,Yuce-Dursun, Basak,Gunduz, Cihan,Ogan, Ayse,Sener, Goksel,Bulut, Mustafa,Yarat, Aysen
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experimental part
p. 617 - 620
(2011/06/10)
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- TETRIACYCLODIPYRANYL COUMARINS AND THE ANTI-HIV AND ANTI-TUBERCULOSIS USES THEREOF
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The present invention relates to tctracyclodipyrano-coumarin compounds of general formula (I), wherein the substituents are defined herein. These compounds exihibit dual biological activities of anti human immunodeficiency virus type 1 (HIV-1) infection a
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Page/Page column 42
(2010/08/18)
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- Cux2 (x =cl, br) as catalysts for pechmann reaction: Synthesis of 4-substituted coumarins
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CuX2 (X=Cl, Br) are found to be efficient catalysts (10 mol%) for the Pechmann condensation reaction of phenols and b-ketoesters to give 4-substituted coumarins under solvent-free conditions. The yields of coumarin derivatives obtained via this
- Wang, Yi,Xu, Feng,Tian, You-Ping,Li, Hui-Li,Wang, Jian-Jun
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experimental part
p. 339 - 341
(2009/12/25)
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- Dually activated organo- and nano-cocatalyzed synthesis of coumarin derivatives
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A wide range of substituted coumarin derivatives were synthesized by refluxing in acetonitrile, ethyl acetoacetate, and ethyl benzoyl acetate with a wide range of structurally diverse phenol derivatives within a short reaction time with a catalytic combination of pyridine dicarboxylic acid as organocatalyst and nanocrystalline ZnO.
- Goswami, Papori
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experimental part
p. 2271 - 2278
(2009/12/03)
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- Ceric ammonium nitrate (CAN): An efficient catalyst for the coumarin synthesis via Pechmann condensation using conventional heating and microwave irradiation
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An efficient and convenient method for the synthesis of substituted coumarins via Pechmann condensation of different phenols with ethylacetoacetate in the presence of ammonium cerium(IV) nitrate as the catalyst in a solvent- free media using both conventional heating and microwave irradiation. Copyright Taylor & Francis Group, LLC.
- Reddy, Y. Thirupathi,Sonar, Vijayakumar N.,Crooks, Peter A.,Dasari, Pavan K.,Reddy, P. Narsimha,Rajitha
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p. 2082 - 2088
(2008/09/21)
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- KAl(SO4)2·12H2O (alum) a reusable catalyst for the synthesis of some 4-substituted coumarins via Pechmann reaction under solvent-free conditions
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A simple, efficient, and practical procedure for the Pechmann condensation using KAl(SO4)2·12H2O (alum) as a non-toxic, reusable, inexpensive, and easily available catalyst is described under solvent-free condition at 65°C. These improved reaction conditions allow the preparation of a wide variety of some new substituted coumarins in high yields (86-96%) and purity under mild reaction conditions. Compared to the classical Pechmann condensation, this new method consistently has the advantage of high yields.
- Azizian, Javad,Mohammadi, Ali A.,Bidar, Ilyar,Mirzaei, Peiman
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experimental part
p. 805 - 808
(2009/09/25)
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- Scandium(III) triflate-catalyzed coumarin synthesis
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Scandium(III) triflate is an excellent catalyst in the von Pechmann condensation. The solvent-free catalytic reactions proceed smoothly with a range of phenols and β-ketoesters in the presence of 10 mol% scandium(III) triflate at 80°C. This simple method affords various 4-substituted coumarins in good to excellent yield and is superior to the classical method in several aspects: solvent-free conditions, short reaction times, a decreased catalyst loading, a mild reaction temperature, and an easy workup. Copyright Taylor & Francis Group, LLC.
- Jung, Keumnyeo,Park, Yun-Jeong,Ryu, Jae-Sang
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experimental part
p. 4395 - 4406
(2009/04/11)
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- Silica sulfuric acid as an efficient and reusable catalyst for the pechmann synthesis of coumarins under solvent-free conditions
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Silica sulfuric acid is used as an efficient catalyst in the Pechmann condensation of phenols with β-keto-esters leading to the formation of coumarin derivatives in excellent yields under solvent-free conditions. It was found that the catalyst could be recycled and reused for several runs.
- Dabiri, Minoo,Salehi, Peyman,Zolfigol, Mohammad Ali,Baghbanzadeh, Mostafa
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p. 677 - 682
(2008/03/12)
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- Alum (KAl(SO4)2·12H2O) catalyzed one-pot synthesis of coumarins under solvent-free conditions
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Alum (KAl(SO4)2·12H2O) is used as an efficient catalyst in the Pechmann condensation of phenol derivatives with β-keto esters leading to the formation of coumarins in excellent yields under solvent-free conditions. This methodology offers significant improvements for the synthesis of coumarins with regard to the yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts and solvents.
- Dabiri, Minoo,Baghbanzadeh, Mostafa,Kiani, Shadi,Vakilzadeh, Yasamin
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p. 997 - 999
(2008/03/17)
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- Microwave-promoted automated synthesis of a coumarin library
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A 30-membered library of coumarins has been synthesized in a microwave-assisted Pechmann reaction using neat trifluoroacetic acid both as an acidic reagent and a reaction medium. Alternatively, polymer-supported sulfonic acid Amberlyst-15 could also be employed to facilitate the formation of coumarins. The use of a specially-built microwave synthesizer with liquid handling tools rendered the automated synthesis of a coumarin library feasible.
- Katkevi?s,Kontijevskis,Mutule,Sūna
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p. 151 - 159
(2008/12/20)
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- Ultrasound-assisted Pechmann condensation of phenols with β-ketoesters to form coumarins, in the presence of bismuth(III) chloride catalyst
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Ultrasound was found to synergistically accelerate the condensation of phenol with β-ketoesters in the presence of BiCl3. In the absence of ultrasound, under the same conditions, the reaction was found to be slow. Thus, the reaction can be carried out in the presence of ultrasound at room temperature (28-30°C), with a considerable reduction of reaction time, with high yield and high purity of coumarins. Copyright Taylor & Francis Group, LLC.
- Patil, Sachin B.,Bhat, Ramakrishna P.,Raje, Vivek P.,Samant, Shriniwas D.
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p. 525 - 531
(2007/10/03)
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- Selectfluor: A simple and efficient catalyst for the synthesis of substituted coumarins under solvent-free conditions
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Selectfluor is used as an alternative catalyst to conventional catalysts for the synthesis of substituted coumarins via Pechmann condensation of phenols with β-ketoesters under solvent-free conditions at 120 °C. This method of synthesis is simple, cost-effective, requires short reaction time, solvent-free and gives good yields.
- Kumar, B. Sunil,Reddy, Y. Thirupathi,Reddy, P. Narsimha,Kumar,Rajitha
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p. 477 - 479
(2007/10/03)
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- Vanadium(III) chloride as an effective catalyst for the Pechmann reaction
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Good yields of substituted coumarins were obtained by a synthetic method involving the Pechmann reaction using vanadium(III)chloride (VCl3) reagent to effect this condensation under solvent-free conditions. 2006 Springer Science+Business Media, Inc.
- Sunil Kumar,Kumar,Srinivasulu,Rajitha,Thirupathi Reddy,Narsimha Reddy,Udupi
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p. 172 - 175
(2007/10/03)
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- Structure-activity relationship of natural and synthetic coumarins inhibiting the multidrug transporter P-glycoprotein
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A set of 32 natural and synthetic coumarins were tested in order to evaluate their activity on human leukemic cells (K562/R7) overexpressing P-glycoprotein (P-gp). Their ability to reduce the P-gp-mediated drug efflux of daunorubicin out of cells was eval
- Raad, Imad,Terreux, Raphael,Richomme, Pascal,Matera, Eva-Laure,Dumontet, Charles,Raynaud, Jean,Guilet, David
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p. 6979 - 6987
(2007/10/03)
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- Skeletal diversity construction via a branching synthetic strategy
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A branching synthetic strategy was used to efficiently generate structurally diverse scaffolds, which span a broad area of chemical descriptor space, and their biological activity against MRSA was demonstrated. The Royal Society of Chemistry 2006.
- Wyatt, Emma E.,Fergus, Suzanne,Galloway, Warren R. J. D.,Bender, Andreas,Fox, David J.,Plowright, Alleyn T.,Jessiman, Alan S.,Welch, Martin,Spring, David R.
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p. 3296 - 3298
(2008/09/19)
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- An efficient ZrCl4 catalyzed one-pot solvent free protocol for the synthesis of 4-substituted coumarins
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A versatile and efficient route to 4-substituted coumarins via a Pechmann reaction using ZrCl4 as the catalyst (10 mol %) is described. This method provides several advantages over alternative procedures such as mild, solvent-free conditions at ambient temperature, and direct isolation of the products in high yields.
- Sharma,Janardhan Reddy,Sree Lakshmi,Radha Krishna
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p. 6119 - 6121
(2007/10/03)
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- Bismuth(III) nitrate pentahydrate - A mild and inexpensive reagent for synthesis of coumarins under mild conditions
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Bismuth(III) nitrate pentahydrate is found to be an efficient catalyst for the Pechmann condensation reaction of phenols and β-ketoesters under solvent-free conditions. The reaction protocol is simple and is followed by aqueous work-up leading to the formation of the corresponding coumarin derivatives in good yield and high purity.
- Alexander, Varughese M.,Bhat, Ramakrishna P.,Samant, Shriniwas D.
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p. 6957 - 6959
(2007/10/03)
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- Sulphamic acid - An efficient and cost-effective solid acid catalyst for the pechmann reaction
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Sulphamic acid (H2NSO3H, SA) is used as an alternative to conventional acid catalysts in the Pechmann condensation of phenols with β-ketoester leading to the formation of substituted coumarin. The method is simple, cost-effective, solvent-free and gives good yields in a short reaction time.
- Singh, Pankajkumar R.,Singh, Devendrapratap U.,Samant, Shriniwas D.
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p. 1909 - 1912
(2007/10/03)
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- Concise Synthesis of Anti-HIV-1 Active (+)-Inophyllum B and (+)-Calanolide A by Application of (-)-Quinine-Catalyzed Intramolecular Oxo-Michael Addition
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(-)-Quinine-catalyzed intramolecular oxo-Michael addition (IMA) of 7-hydroxy-5-methoxy-8-tigloylcoumarins was developed for the enantioselective construction of 2,3-dimethyl-4-chromanone systems in the context of the asymmetric synthesis of anti-HIV-1 act
- Sekino, Etsuko,Kumamoto, Takuya,Tanaka, Tomohiro,Ikeda, Tomoko,Ishikawa, Tsutomu
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p. 2760 - 2767
(2007/10/03)
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- A single-step assembly of coumarin ring skeleton from oxygenated phenols and acetylenic esters by catalytic indium chloride in the absence of solvent
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Ring oxygenated coumarins were obtained in a single-step by condensation of appropriately substituted phenols with acetylenic esters by catalytic amounts of indium chloride in the absence of solvent.
- Kalyanam,Nagarajan,Majeed
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p. 1909 - 1914
(2007/10/03)
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- Compounds for deactivating phospholamban function on Ca-ATPase (phopholamban inhibitors)
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This invention relates to determining the three-dimensional structure of the cytosolic domain of phospholamban (PLB) and its active site from NMR data of sufficiently high resolution for the three-dimensional structure determination. The invention also re
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