- Knoevenagel condensation in aqueous media promoted by 2,2′-bipyridinium dihydrogen phosphate as a green efficient catalyst
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A 2,2′-Bipyridine-based ionic compound named 2,2′-bipyridinium dihydrogen phosphate was synthesized by addition of phosphoric acid to a solution of 2,2′-Bipyridine in dichloromethane. After the characterization using FT-IR, mass, 1H, 13C and 31P NMR techniques, it was used as a Bronsted dicationic acidic catalyst for the promotion of the synthesis of 2-arylidene malononitrile and 5-arylidene barbituric acid derivatives via Knoevenagel condensation reaction in water. Some of the advantages of this method are the utilization of an easy preparable, cost-effective and eco-friendly organic salt as a catalyst within high rates and yields of the reactions, simple and quick work-up and acceptable reusability of the catalyst.
- Darvishzad, Shila,Daneshvar, Nader,Shirini, Farhad,Tajik, Hassan
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p. 2973 - 2984
(2021/04/19)
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- A study on the physical properties of low melting mixtures and their use as catalysts/solvent in the synthesis of barbiturates
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In recent years, deep eutectic solvents have become attractive due to their interesting characteristics such as, physicochemical properties, low cost of components, easiness to prepare, low toxicity, bio-renewability, and biodegradability. In order to make the deep eutectic mixture more cost-effective and renewable, carbohydrate derivatives were linked with deep eutectic mixtures, since, carbohydrates are the most important and widespread renewable compounds on the earth. In this work, we have used low melting mixtures comprised of carbohydrates to create the reaction media for organic transformations. The physical properties such as density, viscosity, acidity, refractive index, surface tension, solubility, glass transition temperature, thermal stability, solvent polarity, and toxicity of the mixture were studied. Low melting mixtures were used as reaction media and catalysts for the effective synthesis of Barbiturates. The reaction between aldehydes and barbituric acid/thiobarbituric acid, and the reaction between aldehydes, barbituric acid/thiobarbituric acid, and malononitrile/dimedone were performed effectively with good to excellent yields. The recyclability of the catalyst/solvent was also established.
- Theresa, Letcy Vincent,Avudaiappan, Govindan,Shaibuna, Machingal,Hiba, Kottayil,Sreekumar, Krishnapillai
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p. 1849 - 1860
(2021/06/17)
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- Preparation and application of triphenyl(propyl-3-hydrogen sulfate)phosphonium bromide as new efficient ionic liquid catalyst for synthesis of 5-arylidene barbituric acids and pyrano[2,3-d]pyrimidine derivatives
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We report synthesis of triphenyl(propyl-3-hydrogen sulfate)phosphonium bromide ([TPPHSP]Br) as a reusable green Br?nsted-acidic ionic liquid catalyst and its application for synthesis of 5-arylidene barbituric acids and pyrano[2,3-d]pyrimidine derivatives by condensation reaction between aromatic aldehydes and barbituric acid or aromatic aldehydes, malononitrile, and barbituric acid in EtOH–H2O in reflux condition with good to excellent yield. The [TPPHSP]Br IL catalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, 1H and 13C nuclear magnetic resonance (NMR), and thermogravimetric (TG) analysis and showed good catalytic activity and reusability.
- Karami, Samira,Momeni, Ahmad Reza,Albadi, Jalal
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p. 3395 - 3408
(2019/04/25)
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- The introduction of two new imidazole-based bis-dicationic Br?nsted acidic ionic liquids and comparison of their catalytic activity in the synthesis of barbituric acid derivatives
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In this article, the preparation of bis-imidazolium hydrogen sulfate and bis-imidazolium perchlorate as two new bis-dicationic Br?nsted acidic ionic liquids based on imidazole is reported. After characterization by FT-IR, mass and NMR spectroscopy and pH titration, the applicability of these reagents is studied in the promotion of the synthesis of 5-arylidene barbituric acids and pyrano[2,3-d] pyrimidinone derivatives. These methods possess some advantages such as ease of preparation of the catalyst, simple work-up procedure, short reaction times, excellent yields, and use of nonorganic solvents during all steps of the reactions and good reusability of the catalysts.
- Daneshvar, Nader,Nasiri, Mitra,Shirzad, Maryam,Safarpoor Nikoo Langarudi, Mohaddeseh,Shirini, Farhad,Tajik, Hassan
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p. 9744 - 9756
(2018/06/18)
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- 2-Phenyl-2,3-dihydrobenzo[ d ]thiazole: A Mild, Efficient, and Highly Active in situ Generated Chemoselective Reducing Agent for the One-Pot Synthesis of 5-Monoalkylbarbiturates in Water
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A metal- and catalyst-free reductive alkylation protocol for the one-pot synthesis of 5-monoalkylbarbiturates from barbituric acids and aldehydes using the in situ generated chemoselective reducing agent 2-phenyl-2,3-dihydrobenzo[ d ]thiazole from 2-aminothiophenol and benzaldehyde is described. The notable advantages of the protocol are operational simplicity, mild reaction conditions, high yield, short reaction time, and simple workup and purification process which make it highly attractive.
- Kalita, Subarna Jyoti,Deka, Dibakar Chandra
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p. 477 - 482
(2017/12/06)
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- A facile single pot synthesis of highly functionalized tricyclic heterocycle compounds via sequential Knoevenagel-Michael addition and their α-glucosidase inhibition, antioxidants and antibacterial studies
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A facile methodology was developed which involved multicomponent single pot reaction which yielded the synthesis of highly functionalized tricyclic-heterocycle compounds (1c-6c) and (1d-7d) in good yields (60-80%). The discovered novel methodology involve
- Ahmed, Faiz,Rauf, Abdul,Sharif, Ahsan,Ahmad, Ejaz,Arshad, Muhammad,Esposito, Breno Pannia,Kaneko, Telma Mary,Qureshi, Ashfaq Mahmood
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p. 761 - 772
(2018/07/15)
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- Reaction of 6-aminouracils with aldehydes in water as both solvent and reactant under FeCl3·6H2O catalysis: Towards 5-alkyl/arylidenebarbituric acids
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5-Alkyl/arylidenebarbituric acids were efficiently synthesized through an FeCl3·6H2O catalyzed domino reaction of 6-aminouracils, water and aldehydes with water serving a dual role as both solvent and reactant, under benign reaction conditions. A study on comparative substrate scope of 6-aminouracil versus barbituric acid showed similar efficacy towards 5-alkyl/arylidenebarbituric acids. The protocol is the first detailed report to prepare regioselectively 5-alkyl/arylidenebarbituric acids starting from 6-aminouracils, which is an alternative and competing strategy to hitherto all known reactions directly employing barbituric acids. the Partner Organisations 2014.
- Kalita, Subarna Jyoti,Mecadon, Hormi,Chandra Deka, Dibakar
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p. 32207 - 32213
(2014/08/18)
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- Nuclear magnetic resonance and molecular modeling study of exocyclic carbon-carbon double bond polarization in benzylidene barbiturates
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Benzylidene barbiturates are important materials for the synthesis of heterocyclic compounds with potential for the development of new drugs. The reactivity of benzylidene barbiturates is mainly controlled by their exocyclic carbon-carbon double bond. In this work, the exocyclic double bond polarization was estimated experimentally by NMR and correlated with the Hammett σ values of the aromatic ring substituents and the molecular modeling calculated atomic charge difference. It is demonstrated that carbon chemical shift differences and NBO charge differences can be used to predict their reactivity.
- Figueroa-Villar, J. Daniel,Vieira, Andreia A.
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p. 310 - 317
(2013/03/13)
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- Reductive C-alkylation of barbituric acid derivatives with carbonyl compounds in the presence of platinum and palladium catalysts
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Effective synthetic procedures for the preparation of mono- and di-C-alkylated barbituric acid derivatives through palladium and platinum catalytic hydrogenation of solutions of barbituric acids (unsubstituted, N-mono, and N,N′-disubstituted barbituric acids) and carbonyl compounds (aliphatic and aromatic aldehydes and ketones).
- Jursic, Branko S.,Neumann, Donna M.
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p. 4103 - 4107
(2007/10/03)
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- Synthesis of a New Class of Uridine Phoshorylase Inhibitors
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A new series of potent uridine phosphorylase inhibitors have been prepared from barbituric acid.Among them 1--5-(m-benzyloxy)benzylbarbituric acid (37, BBBA) is the most promising having a Ki value of 1.1 +/- 0.2 nM wit
- Tzeng, Cherng-Chyi,Panzica, Raymond P.,Naguib, Fardos N.M.,Kouni, Mahmoud H. el
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p. 1399 - 1404
(2007/10/02)
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- CHLOROSULFONATION OF 5,5-DIPHENYLHYDANTOIN AND 5-ARYLIDENEBARBITURIC ACIDS
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5,5-Diphenylhydantoin (1) by heating with chlorosulfonic acid gave a bis-sulfonyl chloride (2) in which the orientation of sulfonation is apparently meta/para.The chloride (2) was converted into 8 sulfonamides (3-10).Barbituric acid has been condensed with aromatic aldehydes to yield 18 5-arylidene derivatives (11-28).The reaction of chlorosulfonic acid with 5-benzylidenebarbituric acid (11) is discussed together with the subsequent reaction of the sulfonyl chloride with amines.The chlorosulfonation of other arylidenebarbituric acids (12-14, 22, 23, 26 and 28) has also been examined. Key words: 5,5-Diphenylhydantoin; 5-arylidenebarbituric acids; chlorosulfonation; sulfonamides; Michael addition.
- Cremlyn, Richard,Bassin, Jatinder P.,Ahmed, Fozia,Hastings, Michael,Hunt, Ian,Mattu, Tajinder
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p. 161 - 172
(2007/10/02)
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