A Green Approach to the Synthesis of Fused Uracils: Pyrano[2,3-d]pyrimidines. ‘On-Water’ One-Pot Synthesis by Domino Knoevenagel/Diels-Alder Reactions
作者:Aleksandra Pałasz
DOI:10.1055/s-0030-1258292
日期:2010.12
exclusively. The presented green methods avoid the use of catalysts, the heating of reaction mixtures for long times at high temperatures, and the use of organic solvents, and make the synthesis of a variety of pyrano[2,3-d]pyrimidines chemically efficient. The results reveal water as the medium of choice for the examined cycloadditions. Diels-Alder reactions - drugs - green chemistry - pyrano[2,3-d]pyrimidines
2-硫代巴比妥酸和N,N-二甲基巴比妥酸与芳族和杂芳族醛的“水上” Knoevenagel缩合反应在没有催化剂的情况下在室温下进行。水性悬浮液中的冷凝迅速发生,从而获得了极好的收率。在室温和吡喃[2,3- d]下研究了巴比妥酸的5-芳基衍生物与乙基乙烯基醚的无溶剂杂Diels-Alder反应具有潜在药理活性的嘧啶类药物的收率很高。在水性悬浮液中进行三组分一锅法合成尿嘧啶环化反应。巴比妥酸,醛和乙基乙烯基醚的反应是在环境温度下进行的,而与巴比妥酸,醛和苯乙烯或N-乙烯基-2-恶唑烷酮的一锅法合成需要将水悬浮液加热至60°C 。与在均质有机介质(二氯甲烷,甲苯)中进行的反应相反,“水上”环加成反应的特点是非对映选择性高。他们允许顺式优先或排他获得的加合物。提出的绿色方法避免了使用催化剂,在高温下长时间加热反应混合物以及使用有机溶剂,从而使化学合成多种吡喃并[2,3- d ]嘧啶有效。结果表明水是所考察的环加成反应的选择介质。
Properties of a furan ring-opening reaction in aqueous micellar solutions for selective sensing of mesalazine
(DFT) was applied to optimize the structure of the colored product and its λmax (the wavelength of maximum absorbance) in dimethylsulfoxide and water. The colored product was considered in three possible structures, and the most possible structures in dimethylsulfoxide and in water were identified by employing the DFT calculations. Both of the most possible structures indicated only a local excitation
开发了一种新颖且有效的基于非偶氮形成的方法,用于痕量美沙嗪(MES)(一种药物芳香胺)的痕量感测。通过呋喃开环反应,将MES与Meldrum的活化呋喃(MAF)试剂简单偶联,即可形成有色产物。在575 nm处检测到深紫色溶液。MES与MAF的反应通过1 H NMR光谱和质谱监测。此外,应用密度泛函理论(DFT)来优化有色产品的结构及其λmax(最大吸收波长)在二甲基亚砜和水中。考虑了有色产物的三种可能的结构,并且通过使用DFT计算确定了二甲基亚砜和水中最可能的结构。在他们的λ两个最可能的结构表明只有局部激发最大值,没有观察到电荷转移。然而,二甲基亚砜中的一种结构表现出通过N C C C部分发生的电荷转移性质。还使用单变量优化方法来获得用于分析的最佳条件。此外,分析响应对三个主要影响参数(反应时间(X 1),Triton X-100浓度(X 2)的依赖性))和MAF浓度(X 3))是通过采用
Reaction of 6-aminouracils with aldehydes in water as both solvent and reactant under FeCl<sub>3</sub>·6H<sub>2</sub>O catalysis: towards 5-alkyl/arylidenebarbituric acids
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 conditions.
Synthesis of a novel tetracationic acidic organic salt based on DABCO and its applications as catalyst in the Knoevenagel condensation reactions in water
Abstract Synthesis of a novel tetracationic acidic organic salt based on DABCO containing two sulfonic acid groups in the skeleton and four hydrogensulfate groups as counterion is described. Its catalytic efficiency in the Knoevenagel condensation of aldehydes with active cyclic methylene compounds in water is investigated. While 2,2'-(phenylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-enone) derivatives
Promoting the Furan Ring‐Opening Reaction to Access New Donor–Acceptor Stenhouse Adducts with Hexafluoroisopropanol
作者:Michèle Clerc、Friedrich Stricker、Sebastian Ulrich、Miranda Sroda、Nico Bruns、Luciano F. Boesel、Javier Read de Alaniz
DOI:10.1002/anie.202100115
日期:2021.4.26
their development. We demonstrate here that 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) promotes the ring‐openingreaction and stabilizes the open isomer, allowing greatly reduced reaction times and increased yields for known derivatives. In addition, it provides access to previously unattainable DASA‐based photoswitches and DASA–polymer conjugates. The role of HFIP and the photochromic properties of