- Synthesis and structure-activity relationship of daphnetin derivatives as potent antioxidant agents
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In this study, daphnetin 1 was chosen as the lead compound, and C-3 or C-4-substituted daphnetins were designed and synthesized to explore the potential relationship between the antioxidant activities and the chemical structures of daphnetin derivatives. The antioxidant activities of the generated compounds were evaluated utilizing the free radical scavenging effect on 2,2-diphenyl-1-picrylhydrazyl, 2,2-azinobis-(3-ethylbenzthiazoline-6-sulfonate) cation, and the ferric reducing power assays, and were then compared with those of the standard antioxidant Trolox. The results showed that the catechol group was the key pharmacophore for the antioxidant activity of the daphnetins. The introduction of an electron-withdrawing hydrophilic group at the C-4 position of daphnetin enhanced the antioxidative capacity, but this trend was not observed for C-3 substitution. In addition, introduction of a a hydrophobic phenyl group exerted negative effects on the antioxidant activity in both the C-3 and C-4 substitutions. Among all of the derivatives tested, the most powerful antioxidant was 4-carboxymethyl daphnetin (compound 9), for which the strongest antioxidant activity was observed in all of the assays. In addition, compound 9 also displayed strong pharmaceutical properties in the form of metabolic stability. To summarize, compound 9 holds great potential to be developed as an antioxidant agent with excellent antioxidant activity and proper pharmacokinetic behavior.
- Xia, Yangliu,Chen, Chen,Liu, Yong,Ge, Guangbo,Dou, Tongyi,Wang, Ping
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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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- 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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- Preparation and pharmacological effects of coumarin derivative and application of coumarin derivative to treatment on pruritus
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The invention relates to preparation of a coumarin derivative 7,8-dihydroxy-4-trifluoromethyl-chromene-2H-chromen-2-one for treating the pruritus symptom, studies of pharmacodynamics on the aspects of a molecular pharmacology mechanism, a pruritus animal model and the like of the coumarin derivative, and a pharmaceutics study applicable to treatment on pruritus. The active compound is definite in pharmacological effect mechanism, is broad-spectrum and effective to treat the pruritus symptom, and can be used for clinical application to treatment on skin diseases.
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Paragraph 0067; 0068; 0069
(2016/11/17)
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- Environmentally sustainable magnetic solid sulfonic acid: An efficient and reusable catalyst for the Pechmann reaction
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Abstract An environmentally benign sulfonic acid nanocomposite based on Fe3O4@SiO2 core-shell magnetic nanoparticles, Fe3O4@SiO2@Et-PhSO3H, was prepared and the acidity and utility of the catalyst were explored for the synthesis of a diverse range of coumarin derivatives under solvent-free conditions. The catalyst shows potential for scale up in the synthesis of coumarins with high purity and was easily separated by using an external magnet. The recovered catalyst was reused in seven cycles without any significant loss of activity.
- Mobaraki, Akbar,Yasham, Shahriar,Movassagh, Barahman
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supporting information
p. 1263 - 1268
(2015/06/02)
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- Synthesis and anticancer activity of 7,8-dihydroxy-4-arylcoumarins
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A series of 7,8-dihydroxy-4-arylcoumarins, the derivatives related to DW532 that was an anti-tumor agent targeting both kinase and tubulin, was prepared by Suzuki coupling reaction. Among them, compounds 6a, 6b, and 6c were found to exhibit anti-prolifera
- Wu, Jianrui,Peng, Ting,Chen, Fang,Leng, Yixin,Tong, Linjiang,Li, Mengyuan,Qu, Rong,Xie, Hua,Ding, Jian,Duan, Wenhu
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p. 366 - 373
(2015/06/22)
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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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- 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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- 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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- 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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- Microwave initiated reactions: Pechmann coumarin synthesis, Biginelli reaction, and acylation
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An energy-efficient protocol has been developed for solvent-free reactions that are mildly exothermic but not spontaneous. The exothermic reaction mixture-on several g-scale-is exposed for about 30 s to low power (about 200 W) microwaves and then the microwave oven is switched off. After this short burst of energy, the exothermic reaction gets initiated and proceeds on its own to completion. A number of coumarins were synthesized by the Pechmann reaction using this strategy.
- Manhas, Maghar S.,Ganguly, Subhendu N.,Mukherjee, Somdatta,Jain, Amit K.,Bose, Ajay K.
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p. 2423 - 2425
(2007/10/03)
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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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- 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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p. 4300 - 4305
(2007/10/03)
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- Complexes of Cu(II) with Some Biologically Active Dihydroxycoumarins
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Complexes of Cu(II) with hydroxycoumarins, viz. esculetin, daphnetin and their 4-methyl and 4-phenyl derivatives have been prepared.The general composition of the complexes is .The water molecules are replaced on reaction with pyridine or ammonia to give complexes of the type (where X = NH3 or C5H5N).IR studies show that more acidic of the two phenolic hydroxyl groups present at C-7 in the ligand is involved in complexation in the parent complexes.Thermal studies on the parent complexes indicate the formation of two intermediate compounds which correspond to the compositions and but only one intermediate, , is formed on heating the pyridine or ammonia adducts.
- Singh, H. B.,Negi, R. K.,Srivastava, Smita
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p. 1026 - 1028
(2007/10/02)
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