18015-04-8Relevant articles and documents
Catalyst-free synthesis of benzimidazole and benzothiazole derivatives by the cleavage of the C–C double bond of 5-arylidenepyrimidine-2,4,6-(1H,3H,5H)-triones
Darehkordi, Ali,Ramezani, Mahin,Rahmani, Fariba,Poor, Mahboobe Amirani
, p. 290 - 294 (2018/04/20)
Background: Benzimidazole and benzothiazole subunits exist in many biologically active molecules, natural products, and synthetic compounds. These compounds have recently gained widespread interest due to their key role in medically important compounds, such as those exhibiting anticancer activity, antimicrobial activity, inhibition of hepatitis C virus NS5B polymerase, p38 kinase inhibitory activity, and anti-inflammatory activity. Methods: 2-Substituted benzimidazole and benzothiazole derivatives have been synthesized by the condensation of 1,2-phenylenediamine or 2-aminobenzothiophenol with 5-arylidenepyrimidine-2,4,6-(1H,3H, 5H)-trione derivatives via cleavage of C-C double bond without using a catalyst in EtOH under reflux conditions. Results: We report here a very simple, novel, efficient, and catalyst-free method for the synthesis of benzimidazole and benzothiazole in good to excellent yields from the treatment of 1,2-phenylenediamine and 2-aminothiophenol with various 5-arylidenepyrimidine-2,4,6(1H,3H,5H)-trione, respectively. This reaction proceeds via cleavage of a C=C double bond and elimination of barbituric acid. Conclusion: This method appears to be general for the synthesis of benzimidazoles and benzothiazoles using 5-arylidenepyrimidine-2,4,6-(1H,3H,5H)-trione derivatives containing various aromatic and heteroaromatic aldehydes such as furfural and thiophene-2-carbaldehyde with electron-withdrawing and electron-releasing groups.
Barbituric acid in the synthesis of fused 1,7-phenanthroline derivatives
Kozlov,Tereshko
, p. 1006 - 1011 (2014/09/30)
New 7-aryl(hetaryl)-7,8,9,10,11,12-hexahydropyrimido[5,4-b][1,7] phenanthroline-9,11-diones have been synthesized by three-component condensation of barbituric acid with quinolin-5-amine and aromatic or heteroaromatic aldehydes.
Reaction of 6-aminouracils with aldehydes in water as both solvent and reactant under FeCl3·6H2O catalysis: Towards 5-alkyl/arylidenebarbituric acids
Kalita, Subarna Jyoti,Mecadon, Hormi,Chandra Deka, Dibakar
, p. 32207 - 32213 (2014/08/18)
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.
Synthesis of fused uracils: Pyrano[2,3-d]pyrimidines and 1,4-bis(pyrano[2,3-d]pyrimidinyl)benzenes by domino Knoevenagel/Diels-Alder reactions
Palasz, Aleksandra
scheme or table, p. 1175 - 1185 (2012/10/07)
Knoevenagel condensation of barbituric acids with aromatic aldehydes containing one or two formyl groups was carried out. 5-Arylidenebarbituric acids underwent smooth hetero-Diels-Alder (HDA) reactions with enol ethers to afford cis and trans diastereoisomers of pyr-ano[2,3-d]pyrimidine-2,4-diones and 5,5′-(1,4-phenylene)-bis[2H-pyrano[2,3-d]pyrimidine-2,4(3H)-dione] derivatives in excellent yields (75-88%). Syntheses were realized by Knoevenagel condensation and HDA reaction in four different reaction conditions: Knoevenagel condensation in water and Diels-Alder reaction in methylene chloride solution, Knoevenagel condensation in water and Diels-Alder reaction without solvent, three-component one-pot reaction in methylene chloride solution, or three-component one-pot reaction in water. All reactions were carried out without catalyst at room temperature. The reactions of malononitrile with Knoevenagel condensation products of barbituric acids and heteroaromatic aldehydes or terephthalaldehyde were examined and did not provide corresponding pyranopyrimidines.
Organocatalysis of c?￡/c?￡N and C?￡C/ C?￡N exchange in dynamic covalent chemistry
Wilhelms, Nadine,Kulchat, Sirinan,Lehn, Jean-Marie
, p. 2635 - 2651 (2013/03/13)
The reversibly formed C?￡N bond plays a very important role in dynamic covalent chemistry and the C?￡N/C?￡N exchange of components between different imine constituents to create dynamic covalent libraries has been extensively used. To facilitate diversity generation, we have investigated an organocatalyzed approach, using L-proline as catalyst, to accelerate the formation of dynamic libraries of [n×n] imine components. The organocatalysis methodology has also been extended, under somewhat modified conditions, to reversible C?￡C/C?￡N exchange processes between Knoevenagel derivatives of barbituric acid and imines, allowing for the generation of increased diversity. Copyright
Facile Knoevenagel and domino Knoevenagel/Michael reactions using gel-entrapped base catalysts
Shinde, Shital,Rashinkar, Gajanan,Kumbhar, Arjun,Kamble, Santosh,Salunkhe, Rajashri
experimental part, p. 1943 - 1951 (2012/01/04)
An efficient method for Knoevenagel condensation of arenecarbaldehydes with active methylene compounds such as barbituric acid and Meldrum's acid in the presence of gel-entrapped base catalysts is reported. The method has been extended to the one-pot synthesis of arylmethylene-bis[3-hydroxycyclohex-2-en-1- one] derivatives from dimedone (=5,5-dimethylcyclohexane-1,3-dione) and arenecarbaldehydes by using domino Knoevenagel/Michael reaction sequence. Copyright
A new and efficient method for the synthesis of 5-arylmethylene- pyrimidine2,4,6-trione under solvent and catalyst free conditions
Sanjeeva Reddy,Nagaraj,Jalapathi
, p. 660 - 663 (2008/09/18)
A new and efficient method has been developed for the synthesis of 5-arylmethylene-pyrimidine-2,4,6-trione without any catalyst and solvent under microwave irradiation. A number of condensation products are prepared in very short reaction time with high yields.
CHLOROSULFONATION OF 5,5-DIPHENYLHYDANTOIN AND 5-ARYLIDENEBARBITURIC ACIDS
Cremlyn, Richard,Bassin, Jatinder P.,Ahmed, Fozia,Hastings, Michael,Hunt, Ian,Mattu, Tajinder
, p. 161 - 172 (2007/10/02)
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.
Clay Catalysis: Dry Condensation of Barbituric Acid with Aldehydes under Microwave Irradiation
Villemin, Didier,Labiad, Bouchta
, p. 3333 - 3337 (2007/10/02)
Barbituric acid (1) and arylcarboxyaldehydes (2) were condensated to 5-(arylmethylene)-2,4,6 (1H,3H,5H) pyrimidinetrione (3) in presence of acidic clay KSF without solvent under microwave irradiation.
