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1.
A highly enantioselective Biginelli reaction promoted by chiral spirocyclic SPINOL-phosphoric acids has been developed. Under the optimized conditions with 5 mol% catalyst loading, a wide range of optically active dihydropyrimidinethiones (DHPMs) were obtained in high yields (up to 98%) with good to excellent enantioselectivities (up to 99% ee). The synthetic utility of this method was demonstrated by the synthesis of chiral precursors of three drugs, including (S)-Monastrol, (S)-L-771688 and (S)-SQ 32926. 相似文献
2.
Benzoyl and ferrocenoyl 3,4-dihydropyrimidin-2(1H)-ones (-thiones) (DHPMs) were synthesized in modest yields via catalyst-free and solvent-free Biginelli condensation of 1-phenylbutane-1,3-dione or 1-ferrocenylbutane-1,3-dione, hydroxyl benzaldehyde, and urea or thiourea. This synthetic protocol revealed that catalysts may not be necessary for the self-assembling Biginelli reaction. The radical-scavenging abilities of the obtained 11 DHPMs were carried out by reacting with 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+?)), galvinoxyl radical, and 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), respectively. The variation of the concentration of these radicals with the reaction time (t) followed exponential function, [radical] = Ae(-t/a) + Be(-t/b) + C. Then, the differential style of this equation led to the relationship between the reaction rate (r) and the reaction time (t), -d[radical]/dt = (A/a)e(-t/a) + (B/b)e(-t/b), which can be used to calculate the reaction rate at any time point. On the basis of the concept of the reaction rate, r = k[radical][antioxidant], the rate constant (k) can be calculated with the time point being t = 0. By the comparison of k of DHPMs, it can be concluded that phenolic ortho-dihydroxyl groups markedly enhanced the abilities of DHPMs to quench ABTS(+?), but the introduction of ferrocenoyl group made DHPMs efficient ABTS(+?) scavengers even in the absence of phenolic hydroxyl group. This phenomenon was also found in DHPM-scavenging galvinoxyl radical. In contrast, the ferrocenoyl group cannot enhance the abilities of DHPMs to scavenge DPPH, and phenolic ortho-dihydroxyl groups still played the key role in this case. 相似文献
3.
Mosstafa Kazemi 《合成通讯》2020,50(10):1409-1445
AbstractMolecules containing dihydropyrimidinone (DHPMs) structures are very important in pharmaceutical and medicinal chemistry due to their excellent biological activities application in synthesis of natural products. Biginelli condensation reaction between an aldehyde, urea/thiourea and a carbonyl compound is the most popular strategy for the synthesis of dihydropyrimidinones. Magnetic recoverable nanocatalysts can be readily separated from reaction medium by using an external magnet, without the need for filtration, centrifugation or other tedious workup processes. In recent times, the catalytic potential of magnetically recoverable nanocatalysts was evaluated in a variety of Biginelli reactions. In this review, we focus on the application of magnetically recoverable gold nanocatalysts in Biginelli synthesis of dihydropyrimidinone derivatives. 相似文献
4.
Here we demonstrate on the synthesis of 3,4-dihydropyrimidin-2-ones (DHPMs) and their derivatives through a three-component condensation reactions of aldehyde, β-ketoester and urea or thiourea using mesoporous aluminosilicate (AlKIT-5) nanocage as catalyst and acetonitrile as solvent under reflux conditions. The catalyst was found to be highly active and selective, affording a high yield of DHPMs. Compared to the classical Biginelli reaction conditions, this new approach consistently has the advantage of excellent yields (80-96%) and short reaction times, 3.0-4.0 h. The effect of the acidity and the concentration of the catalyst on the above process was investigated. We also demonstrate the synthesis of various multifunctional Biginelli compounds using the highly active AlKIT-5 catalysts. 相似文献
5.
Qingbao Song Xiaoxia An Fengfeng Che Tianhua Shen 《Journal of heterocyclic chemistry》2015,52(5):1496-1502
Di‐DACH‐pyridylamide ligands, symmetrical bridged bis‐Schiff base, and spiro pyrrolizines as catalysts in the synthesis of dihydropyrimidinethiones (DHPMs) using the Biginelli reaction is first reported. This new protocol has the advantages of environmental friendliness, short reaction time, excellent yields, and simple post‐treatment procedure. A series of DHPMs were obtained in high yields (up to 98%) in only 6 h. Moreover, based on the optimized condition, a novel Biginelli‐like reaction was first developed. 相似文献
6.
对近年来手性2-氨基-1-苯基乙醇类药物的不对称合成方法进行了总结和概述. 重点介绍了不对称氢化、CBS还原、不对称Henry反应等新方法在2-氨基-1-苯基乙醇类药物如R-沙丁胺醇、R-沙美特罗和D-索他洛尔等合成中的应用. 相似文献
7.
8.
The asymmetric aldol reaction is one of the most powerful synthetic tools for carbon–carbon bond-forming reactions. This method provides a beneficial route to access chiral β-hydroxy carbonyl compounds, which are versatile synthetic motifs found in biologically active natural products and pharmaceutically attractive intermediates. The aim of this review is to provide an overview of the many contributions and recent advances in the field of organocatalytic asymmetric aldol reactions. 相似文献
9.
By using Hf(OTf)4 as catalyst, a series of 2-selenoxo DHPMs have been synthesized efficiently in good yields by Biginelli reaction with selenourea as starting material. 相似文献
10.
In this communication, we report an asymmetric Friedel-Crafts reaction of indoles with imines catalyzed by a bifunctional cinchona alkaloid catalyst. This is the first efficient organocatalytic asymmetric Friedel-Crafts reaction of indoles with imines. This reaction is operationally simple and, unprecedentedly, affords high enantioselectivity for a wide range of indoles and both aryl and alkyl imines. This establishes a direct, convergent, and versatile approach to optically active 3-indolyl methanamines, a structural motif embedded in numerous indole alkaloids and synthetic indole derivatives. 相似文献
11.
具有C_(3~-)和C_(4~-)单元并含有其它官能团的化合物,是合成多种有用化合 物很好的原材料。尤其是光学活性C_(3~-)和C_(4~-)有机合成单元对制备药物和精 细化学产品是非常重要的中间体。应用具有立体专一性酶的微生物转化过程,可不 对称合成光学活性物质。本文阐述了用微生物酶合成手性C_(3~-)和C_(4~-)单元的 最新进展。 相似文献
12.
Polymer-supported 4-aminoformoyldiphenylammonium triflate (PS-AFDPAT) was used as an effective catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) via the Biginelli reaction. This immobilized catalyst could be easily recovered by simple filtration and recycled for 10 runs without significant decrease of the catalytic activity. 相似文献
13.
An efficient synthesis of benzoxazole-substituted 3,4-dihydropyrimidinones(DHPMs) using trifluoro acetic acid as the catalyst for the first time from an aldehyde,β-keto ester and benzoxazole-substituted urea/thiourea under solvent-free conditions is described.Compared to the classical Biginelli reaction conditions,this new method consistently has the advantage of excellent yields(80-91%) and short reaction time(40-130 min) at reflux temperature. 相似文献
14.
15.
Zhen Xu Yangyang Jiang Shuang Zou 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):791-795
AbstractThe three-component Biginelli reaction using aldehyde, thiourea, and 1,3-dicarbonyl compounds was performed smoothly in ethyl lactate (EL) with the catalysis of trimethylsilyl chloride (TMSCl). A class of 3,4-dihydropyrimidinthiones (DHPMs) were synthesized in good to excellent yields via the bio-based solvent mediated catalytic protocol. 相似文献
16.
Marigo M Kjaersgaard A Juhl K Gathergood N Jørgensen KA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(10):2359-2367
The first catalytic asymmetric direct Mannich reaction of malonates and beta-keto esters has been developed. Malonates react with an activated N-tosyl-alpha-imino ester catalyzed by chiral tert-butyl-bisoxazoline/Cu(OTf)(2) to give the Mannich adducts in high yields and with up to 96% ee. These reactions create a chiral quaternary carbon center and it is demonstrated that this new direct Mannich reactions provides for example a new synthetic procedure for the formation of optically active beta-carboxylic ester alpha-amino acid derivatives. A series of different beta-keto esters with various ester substituents has been screened as substrates for the catalytic asymmetric direct Mannich reaction and it was found that the best results in terms of yield, diastereo- and enantioselectivity were obtained when tert-butyl esters of beta-keto esters were used as the substrate. The reaction of different beta-keto tert-butyl esters with the N-tosyl-alpha-imino ester gave the Mannich adducts in high yields, diastereo- and enantioselectivities (up to 95% ee) in the presence of chiral tert-butyl-bisoxazoline/Cu(OTf)(2) as the catalyst. To expand the synthetic utility of this direct Mannich reaction a diastereoselective decarboxylation reaction was developed for the Mannich adducts leading to a new synthetic approach to attractive optically active beta-keto alpha-amino acid derivatives. Based on the stereochemical outcome of the reactions, various approaches of the N-tosyl-alpha-imino ester to the chiral bisoxazoline/Cu(II)-substrate intermediate are discussed. 相似文献
17.
An efficient synthesis of 3,4-dihydropyrimidinones or thiones (DHPMs) is described, using silica-supported heteropoly acid H3PW12O40/SiO2 (PW/SiO2) for the first time as the catalyst from an aldehyde, β-keto ester and urea or thiourea in acetonitrile. Compared to the classical Biginelli reaction conditions, this method consistently has the advantage of excellent yields, mild reaction conditions, ease of workup, survival of different functional groups, and short reaction times. 相似文献
18.
不对称三组分Kabachnik-Fields反应合成光学活性的α-氨基膦酸酯,由于其多组分反应自身所具有的独特优势,近年来已成为一个非常有吸引力的研究领域.从手性催化剂催化和光学活性底物诱导两方面综述了不对称Kabachnik-Fields反应合成手性α-氨基膦酸酯及其衍生物的最新研究进展,重点介绍了手性催化剂与手性底物构型对反应立体选择性的影响及其有关反应机理.最后提出了不对称多组分Kabachnik-Fields反应研究中存在的一些问题,并对其今后的发展方向进行了展望. 相似文献
19.
Landa A Minkkilä A Blay G Jørgensen KA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(13):3472-3483
A new, short, and simplified procedure for the synthesis of optically active pyridine derivatives from pro-chiral pyridine-N-oxides is presented. The catalytic and asymmetric Mukaiyama aldol reaction between ketene silyl acetals and 1-oxypyridine-2-carbaldehyde derivatives catalyzed by chiral copper(II)-bis(oxazoline) complexes gave optically active 2-(hydroxyalkyl)- and 2-(anti-1,2-dihydroxyalkyl)pyridine derivatives in good yields and diastereoselectivities, and in excellent enantioselectivities-up to 99 % enantiomeric excess. As a synthetic application of the developed method, a full account for the asymmetric total synthesis of a nonnatural indolizine alkaloid is provided. 相似文献
20.
Jensen JF Svendsen BY la Cour TV Pedersen HL Johannsen M 《Journal of the American Chemical Society》2002,124(17):4558-4559
Currently, the most effective and economic way to convert an alkene into an optically active alcohol is the two-step sequence: hydrosilylation/oxidation. Much work has been devoted to elucidating effective catalysts for this process, but hitherto only one effective and highly stereoselective process has been available. Herein we present a novel catalytic system for the asymmetric hydrosilylation of aromatic alkenes, giving the products in high yields and with the highest enantioselectivity (up to 99% ee) ever observed for this reaction. The reaction works efficiently for a variety of substituted aromatic alkenes, giving access after Tamao oxidation to almost optically pure benzylic alcohols in high yields. 相似文献