Photo-oxidation of 5-acetyl-3,4-dihydropyrimidin-2(1H)-ones

A variety of Biginelli 5-acetyl-3,4-dihydropyrimidin-2(1H)-ones are efficiently oxidized to their corresponding pyrimidin-2(1H)-one derivatives upon UV irradiation under argon atmosphere in chloroform solution. The nature of the additional substituent on the phenyl ring located on C-4 of the heterocyclic ring influences the rate of reaction. An electron-transfer induced photoreaction is proposed based on the formation of HCl and CH₂Cl₂.     

Condensation of 5-Acetyl-3,4-dihydropyrimidin-2(1H)-ones with Hydrazine

Russian Journal of Organic Chemistry - 3,4-Dihydropyrimidines obtained by the Biginelli reaction react with hydrazine to give a mixture of N-[(3,5-dimethyl-1H-pyrazol-4-yl)(R)methyl]ureas and...     

Oxidation of 3,4-dihydropyrimidin-2（1H）-ones with nitrosonium （NO^＋）

3,4-Dihydropyrimidin-2(1H)-ones (DHPMs) were oxidized with 1.2 equiv. of nitrosonium tetrafluoroborate (NO⁺BF₄⁻) to pyrimidin-2(1H)-ones in acetonitrile at room temperature in high yields.     

Facile aromatization of 3,4-dihydropyrimidin-2(1H)-ones(DHPMs) by iodine

A facile aromatization of 3,4-dihydropyrimidin-2(1H)-ones using iodine in dimethyl sulfoxide under microwave irradiation was carried out which is more efficient and gives high yield in less time;presently it is the most important catalyst for dehydrogenation.     

微波辐射促进选择性合成4,6-二芳基-3,4-二氢嘧啶-2(1H)-酮和嘧啶-2(1H)-酮

探讨了在微波加热条件下,芳香醛、取代苯乙酮和尿素的三组分反应在N,N-二甲基甲酰胺(DMF)中制得4,6-二芳基-3,4-二氢嘧啶-2(1H)-酮类化合物,收率为68%～84%.若在反应体系中加入三甲基氯硅烷,该三组分反应则高产率(66%～87%)地生成相应的脱氢产物4,6-二芳基嘧啶-2(1H)-酮类化合物.该反应具有反应条件温和、产物收率高、操作方便等优点,为4,6-二芳基-嘧啶-2(1H)-酮类药物中间体的合成提供了一条全新的路线.     

CoCl2·6H2O催化合成3,4-二氢嘧啶-2-酮衍生物

3 ,4 二氢嘧啶 2 酮类化合物可用作钙拮抗剂、降压剂、α1ａ 拮抗物等而成为近年来生物活性有机杂环化合物研究的热点之一[1 ] 。通常该类化合物是用Ｂｉｇｉｎｅｌｉ[2 ,3] 反应得到的。为了提高其产率 ,人们作了大量的研究工作[4,1 1 ] 。本文利用Ｃｏ Ｃｌ2 6Ｈ2 Ｏ作催化剂 ,乙醇作溶剂 ,乙酰乙酸乙酯、芳香醛和脲一锅煮合成 3,4 二氢嘧啶 2 酮 ,同时考查了芳香醛的取代基及乙酰丙酮对产物收率的影响。反应方程式如下 :1　实验部分1 1　仪器与试剂熔点用毛细管法测定 ,温度计未校正。Ｅ ＱＵＩＮＯＸ5 5红外光谱仪 (ＫＢｒ压片 ) ;…     

Cost-effective ionic liquid for environmentally friendly synthesis of 3,4-dihydropyrimidin-2(1H)-ones

Abstract

A simple, efficient and environmentally friendly process for synthesis of 3,4-dihydropyrimidinones using a one-pot three-component condensation of aromatic aldehydes, β-dicarbonyl compounds, and urea/thiourea is discussed. The cost-effective, new generation ionic liquid (IL), tri-(2-hydroxyethyl) ammonium acetate was used as both solvent and catalyst. The reactions were carried out using both conventional heating and microwave energy. Application of IL technology with microwave energy represents an attractive and rapid alternative to the conventional acid–base catalyzed thermal processes.     

邻甲基苯磺酸铜催化"一锅法"合成3,4-二氢嘧啶-2(1H)-酮

二氢嘧啶酮(DHPMs)及其衍生物具有广泛的生物活性,如抗病毒、抗肿瘤、抗癌、抗高血压及消炎等作用[1].此外,DHPMs及其衍生物作为钙通道阻滞剂、α1a-对抗剂和神经肽Y的对抗剂,显示出良好的药理活性[2].更重要的是,最近几种含二氢嘧啶酮-5-羧酸盐的海洋生物碱被成功分离出来,并表现出重要的生物学性质[3],某些可以阻止HIVgp-120-CD4键的形成,是一种潜在的HIV抑制剂[4].因此,对DHPMs及其衍生物的研究成为生物活性有机杂环化合物的研究热点之一.     

Chemical resolution of enantiomers of 3,4-dihydropyrimidin-2(1H)-ones using chiral auxiliary approach

Inherently racemic DHPMs have been resolved using chemical resolution methodology by appending enantiopure chiral auxiliary at N-1 or N-3 position of the DHPMs, leading to the formation of both diastereomers, which were separated chromatographically to obtain both enantiomers (ee upto 99.9%) of DHPMs, after removal of the auxiliary. Absolute configuration of the enantiomers has been assigned.     

1-Methyl-2-oxopyrrolidinium perchlorate ionic liquid in synthesis of 5-ethoxycarbonyl-3,4-dihydropyrimidin-2(1H)-ones

Russian Journal of General Chemistry - A multicomponent Biginelli reaction in a solvent-free conditions catalyzed by 1-methyl-2-oxopyrrolidinium perchlorate ionic liquid was studied. The...     

Efficient Ce(NO3)3 x 6H2O-catalyzed solvent-free synthesis of 3,4-dihydropyrimidin-2(1H)-ones

Cerium(III) nitrate hexahydrate efficiently catalyzes the three-component Biginelli reaction under solvent-free conditions of an aldehyde, a beta-keto ester or beta-diketone and urea or thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones or -thiones in excellent yields.     

Light-induced dehydrogenation of 3,4-dihydropyrimidin-2(1H)-ones

Abstract  

UV light irradiation of Biginelli 3,4-dihydropyrimidin-2(1H)-ones in chloroform in an argon atmosphere leads to dehydrogenation of these compounds to their corresponding pyrimidin-2(1H)-ones in excellent yields. Irradiation in the same solvent under an oxygen atmosphere generates, in addition, various hitherto unidentified products. A light-induced electron transfer from the substrate to the solvent is proposed as the initial event, supported by the detection of dichloromethane and hydrogen chloride in the photolysate.     

氯化镉催化三组分“一锅法”合成4,6-二芳基-3,4-二氢嘧啶-2(1H)-酮的研究

在氯化镉催化作用下,以环己烷为溶剂,芳香醛、芳香酮和脲三组分"一锅法"合成了一系列4,6-二芳基-3,4-二氢嘧啶-2(1H)-酮化合物。考察了溶剂和催化剂用量对产率的影响。通过IR、1H NMR、13C NMR和元素分析对产品结构进行了表征。该合成方法具有操作简单、反应时间短、反应条件温和,产率高等优点。     

Synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by nafion-H under ultrasound irradiation and solvent-free conditions

A novel synthesis of 3,4-dihydropyrimidin-2-(1H)-ones by one-pot cyclocondensation of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea using nafion-H as the catalyst under ultrasound irradiation and solvent-free conditions was developed. Compared with the classical Biginelli reactions, this method consistently enjoys the advantages of mild reaction conditions, excellent yields, easy work up and short reaction time.     

Chlorophyll triggered one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones via photo induced electron transfer reaction

The photocatalytic potential of chlorophyll has been investigated for the facile synthesis of dihydropyrimidinones utilizing concentrated solar irradiation towards sustainable energy solutions. This, one-pot, multicomponent Biginelli reaction, which involves a photoinduced electron transfer (PET) mechanism, affords a green and efficient approach for the transformation of the commercial aldehydes, β-keto ester and urea into valuable 3,4-dihydropyrimidin-2(1H)-ones with wide substrate scope and diversity. These improved reaction conditions allow the formation of a variety of substituted dihydropyrimidinones with high yields and purity in a short duration of time and mild reaction conditions.