- Stereoselective intramolecular coupling of barbituric acids with aliphatic ketones and O-methyl oximes by electroreduction: Radical cyclization mechanism supported by DFT study
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The electroreductive intramolecular coupling of barbituric acids with aliphatic ketones gave five- and six-membered cyclized products stereospecifically. When the same reactions were carried out with SmI2, only a five-membered cyclized product was formed as the single stereoisomer different from that obtained by the electroreduction. The cyclized products were stereospecifically transformed to the corresponding deoxygenated compounds by reduction with Et3SiH-BF3·Et2O. Similarly, the electroreductive intramolecular coupling of barbituric acids with O-methyl oximes gave five- and six-membered cyclized products. The DFT calculations suggested that the electroreductive intramolecular coupling proceeds through the protonated radical generated by one-electron transfer and subsequent protonation to the barbituric acid moiety.
- Kise, Naoki,Tuji, Takashi,Sakurai, Toshihiko
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- Method for preparing barbituric acid hydrocarbylation derivative by using ferrous complex
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The invention relates to a method for preparing a barbituric acid hydrocarbylation derivative by using a ferrous complex, which comprises the steps of carrying out coupling reaction at room temperature by using barbituric acid and alcohol as raw materials and the ferrous complex containing an ortho-carboryl benzothiazole structure as a catalyst to prepare the barbituric acid hydrocarbylation derivative. Compared with the prior art, the method has the advantages that the ferrous complex containing the ortho-carboryl benzothiazole structure is applied to catalysis of coupling reaction of barbituric acid and alcohol, the barbituric acid hydrocarbylation derivative is prepared by a one-pot method, the barbituric acid hydrocarbylation derivative is synthesized by using simple, easily available and cheap raw materials at room temperature, and the method has the advantages of low catalyst use equivalent, mild reaction conditions, high substrate universality and high yield.
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Paragraph 0027; 0033-0036
(2021/07/17)
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- Method for synthesizing 5-substituted barbituric acid derivative under catalysis of rare earth chloride
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The invention belongs to the technical field of synthetic chemistry, and particularly relates to a method for synthesizing a 5-substituted barbituric acid derivative under the catalysis of a rare earth chloride. The preparation method comprises: dissolving a halogenated hydrocarbon and 1,3-dimethyl barbituric acid in an organic solvent, carrying out a reaction for 6-10 h at a room temperature by using a rare earth chloride as a catalyst, and separating and purifying to obtain the 5-substituted barbituric acid derivative. According to the invention, the method has characteristics of simple andenvironmentally-friendly synthesis process, excellent selectivity, high yield and wide substrate range, and further has wide application value in the fields of biology, pharmaceutical chemistry industry and the like.
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Paragraph 0023-0025
(2020/01/03)
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- Thermophysical study of several barbituric acid derivatives by differential scanning calorimetry (DSC)
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The present study reports a differential scanning calorimetry (DSC) study of the barbituric acid derivatives: 1,3-dimethylbarbituric acid [CAS 769-42-6], 5,5-dimethylbarbituric acid [CAS 24448-94-0], 1,3-diethylbarbituric acid [CAS 32479-73-5], 1,3,5-trimethylbarbituric acid [CAS 7358-61-4], 1,5,5-trimethylbarbituric acid [CAS 702-47-6], and tetramethylbarbituric acid [CAS 13566-66-0] in the temperature interval from T = 268 K to their respective melting temperatures. Temperatures, enthalpies and entropies of fusion, and the heat capacities of the solid compounds as a function of temperature are reported.
- Temprado, Manuel,Roux, Maria Victoria,Ros, Francisco,Notario, Rafael,Segura, Marta,Chickos, James S.
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experimental part
p. 263 - 268
(2011/10/05)
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- Mono C-alkylation and mono C-benzylation of barbituric acids through zinc/acid reduction of acyl, benzylidene, and alkylidene barbiturate intermediates
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Through systematic exploration of reaction conditions, very efficient preparative procedures for obtaining large quantities of substituted 5-alkyl and 5-benzylbarbituric acids were developed. The procedure involves a two step preparation in which the second step is zinc dust/acid reduction. For preparation of 5-alkylbarbiturates, the first step is the preparation of either 5-acyl or 5-alkylidenebarbiturate. If 5-benzylbarbiturate is the target product, then the first step includes the preparation of 5-benzylidene. Regardless of the nature of the first step, all reactions presented synthetic yields around 90% and isolation and purification involves only crystallization.
- Jursic, Branko S.,Stevens, Edwin D.
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p. 2203 - 2210
(2007/10/03)
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- Reactions of 5-dihydrocotarnyl-1,3-dimethylbarbituric acid and other cotarnine derivatives with 1,3-dimethylbarbituric acid. X-ray diffraction analysis of a 5,5-spiro derivative of 1,3-dimethylbarbituric acid
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6-Methyl-4-methoxy-5,6,7,8-tetrahydro-2H-[1,3]dioxolo[4,5-g] isoquinolin-5-ol (cotarnine) and its derivatives, namely, 5-dihydrocotarnyl-1,3-dimethylbarbituric acid, dihydrocotarnylnitromethane, and dihydrocotarnylphenylacetonitrile, react with an excess
- Krasnov,Kartsev,Khrustalev
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p. 1540 - 1544
(2007/10/03)
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- Relative reactivity of methyl iodide to ethyl iodide in nucleophilic substitution reactions in acetonitrile and partial desolvation accompanying activation
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Through the examination of empirical correlations involving activation parameters for nucleophilic substitution of methyl iodide and of ethyl iodide, nucleophiles have been classified into three series: (1) nucleophiles with two equivalent reaction sites, (2) nucleophiles with a chlorine atom in the para-position, and (3) nucleophiles with a single reaction site. Three types of partial desolvation processes accompanying activation have been deduced on the basis of these classifications. A major factor determining the relative reactivity of methyl iodide to ethyl iodide in the substitution reaction of an anionic nucleophile having a single reaction site in acetonitrile (kMeI/kEtI) is suggested to be partial desolvation around the nucleophilic center on going from reactant to transition-state.
- Kondo, Yasuhiko,Urade, Miyuki,Yamanishi, Yukari,Chen, Xinyu
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p. 1449 - 1454
(2007/10/03)
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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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- Reaction of 1,3-Dialkylbarbituric acids with aliphatic amines
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On heating triethylammonium 1,3-dimethylbarbiturate, 1,3-dimethylthiobarbiturate, and 1,3-diphenylbarbiturate occurs dealkylation of triethylamine to afford in high yields the corresponding 5-ethyl substituted barbituric acids. The cleavage of alkyl groups happened also efficiently with tributyl, tribenzyl, and dimethylbenzylammonium salts, and less efficiently with trimethylammonium and diethylammonium salts. These reactions are characteristic only of 1.3-disubstituted barbituric acids; the barbituric acid and its 1-alkyl derivatives under these conditions suffer degradation.
- Krasnov
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p. 280 - 284
(2007/10/03)
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- Cpecificy of Metylation by Dimethyl Sulfate of Barbituric Acid Salts and Alkyl Derivatives
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Metylation of mono- and dianionic forms of barbituric acid, its C- and N-alkyl derivatives with dimethylsulfate is studied. The methylation of monoanions occurs at the C5 carbon or O4(6) oxygen atoms, while that of dianions presumably at N1(3) nitrogen atoms. The selectivity of the dianions metylation at the nitrogen atoms increases in going from potassium to sodium and even more to lithium salts.
- Krasnov,Slesarev
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p. 543 - 548
(2007/10/03)
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- ALKYLATION OF 1,3-DIMETHYLBARBITURIC ACID BY ALKYL IODIDES
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The alkylation of 1,3-dimethylbarbituric acid by methyl iodide, ethyl iodide, and isopropyl iodide in the presence of triethylamine was investigated.The kinetics of the process were studied, and it was shown that the steric and electronic factors affect the rate of the alkylation reactions.Only the products from alkylation at the C5 atom are formed in the case of methyl iodide, and concurrent alkylation at the C5 and O4(6) atoms is observed with ethyl iodide and isopropyl iodide.
- Krasnov, K. A.,Slesarev, V. I.,Artem'eva, Z. L.
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p. 1402 - 1405
(2007/10/02)
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