Tetrahedron最新文献_第2页

Sustainable aqueous-mediated one-pot synthesis of 2-hydroxy-5-oxo-5,6,7,8-tetrahydro-4H-chromene and coumarin derivatives using taurine as the green bioorganic catalyst 以牛磺酸为绿色生物有机催化剂，在水介导下可持续地一步合成 2-羟基-5-氧代-5,6,7,8-四氢-4H-色烯和香豆素衍生物

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-28 DOI: 10.1016/j.tet.2024.134346

{"title":"Sustainable aqueous-mediated one-pot synthesis of 2-hydroxy-5-oxo-5,6,7,8-tetrahydro-4H-chromene and coumarin derivatives using taurine as the green bioorganic catalyst","authors":"","doi":"10.1016/j.tet.2024.134346","DOIUrl":"10.1016/j.tet.2024.134346","url":null,"abstract":"<div><div>In this study, two taurine-catalyzed, aqueous-mediated methodologies were reported for the synthesis of 4-aryl-2-hydroxy-7,7-dimethyl-5,6,7,8-tetrahydro-4H-chromen-5-one (3a-j) and 3-substituted coumarin derivatives (3′a-f) under reflux conditions. These methodologies entail the use of substituted aromatic aldehydes, diethyl malonate, and dimedone as reagents for the sustainable synthesis of 2-hydroxy-tetrahydro-4H-chromene derivatives via the Knoevenagel-Michael cascade, as well as the use of substituted salicylaldehyde with diethyl malonate or ethyl 3-oxobutanoate for the efficient synthesis of coumarin derivatives via the Knoevenagel-transesterification reaction. These strategies emphasize environmental sustainability and are designed as one-pot processes, ensuring simplicity and convenience. The methods deliver high yields and are cost-effective, significantly reducing reaction times, enhancing step efficiency, and are successful at the multigram level. Notably, the taurine catalyst demonstrates exceptional reusability, maintaining its activity for up to five cycles without notable degradation. The catalyst is easily recoverable through filtration, and the overall procedure is streamlined, requiring no additional purification steps. These attributes collectively contribute to the green chemistry paradigm by minimizing waste and energy consumption, thus offering a practical and efficient approach to the synthesis of these important organic compounds.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multicomponent synthesis of 7-(diethylamino)coumarin–pyrrolo[3,4-b]pyridin-5-one conjugates and modulation of their twisted intramolecular charge transfer (TICT) processes 7-(二乙基氨基)香豆素-吡咯并[3,4-b]吡啶-5-酮共轭物的多组分合成及其扭曲分子内电荷转移（TICT）过程的调制

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-28 DOI: 10.1016/j.tet.2024.134335

{"title":"Multicomponent synthesis of 7-(diethylamino)coumarin–pyrrolo[3,4-b]pyridin-5-one conjugates and modulation of their twisted intramolecular charge transfer (TICT) processes","authors":"","doi":"10.1016/j.tet.2024.134335","DOIUrl":"10.1016/j.tet.2024.134335","url":null,"abstract":"<div><div>By coupling an Ugi-Zhu three-component reaction to a cascade sequence (<em>aza</em> Diels-Alder cycloaddition/<em>N</em>-acylation/decarboxylation/dehydration) into a one-pot process, seven new 7-(diethylamino)coumarin-pyrrolo[3,4-<em>b</em>]pyridin-5-one <em>bis</em>-heterocyclic conjugates were synthesized in moderate overall yields (15–38 %). Next, the photophysical properties of all products were determined using UV–Vis and fluorescence spectroscopy. These products exhibited fluorescence quantum yields (FQY) ranging from 17 % to 25 %. In contrast, one of their precursors, the free 7-(diethylamino)-3-carbaldehyde displayed a low FQY of 2 %, and, also exhibited dual emission across all solvents used for the measurements. The increase in quantum yield observed upon incorporation of the coumarin moiety into MCR products was attributed to the inhibition of the twisted intramolecular charge transfer (TICT) process. This one naturally occurs in the free coumarin but was suppressed in the products due to a decrease in the acceptor strength of the substituent at position 3 of the coumarin moiety. Furthermore, the electronic structure of the compounds was computed by DFT/TD-DFT calculations allowing to determine which molecular orbitals (MO) were involved in the electronic transitions.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Advancements in the selective transformation of olefins to new C–C bonds through cooperative catalysis involving electrochemistry and transition metals 通过电化学和过渡金属的协同催化，推进烯烃向新 C-C 键的选择性转化

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-28 DOI: 10.1016/j.tet.2024.134330

引用次数: 0

Synthesis and applications of optically pure trans-2-(3,5-dimethylphenoxy)cyclohexan-1-ol as chiral auxiliary for preparation of α-substituted carboxylic acid derivatives 光学纯反式-2-(3,5-二甲基苯氧基)环己-1-醇作为制备α-取代羧酸衍生物的手性助剂的合成与应用

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-28 DOI: 10.1016/j.tet.2024.134326

引用次数: 0

A short approach to cytogenin and first total synthesis of aspergisocoumarin A and fusarimarin C 细胞苷元的简易合成方法以及曲霉香豆素 A 和 fusarimarin C 的首次全合成

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-26 DOI: 10.1016/j.tet.2024.134343

引用次数: 0

A classical peptide coupling approach for the total synthesis of simnotrelvir 用于全合成 simnotrelvir 的经典肽偶联方法

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-26 DOI: 10.1016/j.tet.2024.134342

引用次数: 0

Facile synthesis of spiro-heterocycles through one-pot multicomponent [3 + 3] cross 1,3-dipolar cycloaddition reactions 通过单锅多组分[3 + 3]交叉 1,3-二极环加成反应轻松合成螺环杂环

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-26 DOI: 10.1016/j.tet.2024.134328

引用次数: 0

PPh3 promoted stereospecific synthesis of ethyl α-chloroacrylates from ethyl trichloroacetate and arylaldehydes PPh3 促进以三氯乙酸乙酯和芳基醛为原料立体特异性合成 α-氯丙烯酸乙酯

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-26 DOI: 10.1016/j.tet.2024.134341

引用次数: 0

Tuning the photophysical and NLO properties of β-diketonates derived from coumarin-triphenylamine-chalcones: Effect of the BF2 group 调谐香豆素-三苯胺-查耳酮衍生的 β-二酮酸酯的光物理和 NLO 特性：BF2 基团的影响

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-26 DOI: 10.1016/j.tet.2024.134338

{"title":"Tuning the photophysical and NLO properties of β-diketonates derived from coumarin-triphenylamine-chalcones: Effect of the BF2 group","authors":"","doi":"10.1016/j.tet.2024.134338","DOIUrl":"10.1016/j.tet.2024.134338","url":null,"abstract":"<div><div>Herein the synthesis of three difluoroboron β-diketonate complexes (<strong>7a-c</strong>) and one chalcone (<strong>7d</strong>) with coumarin and triphenylamine fragments is described. The effect of the inclusion of the difluoroboron (BF<sub>2</sub>) group and a phenyl linker on the photophysical properties, intramolecular charge transfer (ICT) and nonlinear optical (NLO) properties was studied. These dyes exhibited excellent ICT properties due to their A-π-D and D-π-A-π-D type push-pull configuration. Thus, all compounds presented a strong solvatochromism, given the absorption and emission maxima shifted to red because of the increase in the polarity of the medium. In addition to this, <strong>7a-d</strong> showed the formation of a twisted intramolecular charge transfer (TICT) state, which quenched fluorescence in polar solvents. Compounds <strong>7a</strong>, <strong>7b</strong> and <strong>7d</strong> exhibited aggregation-induced emission (AIE) in MeCN/H<sub>2</sub>O mixtures, while <strong>7c</strong> did not have this behavior. In addition, all compounds showed emission in the solid state. Using DFT and TD-DFT calculations, the molecular geometries of the ground state S<sub>0</sub> and the first excited state S<sub>1</sub> were elucidated, which confirmed the formation of a TICT state. Furthermore, the theoretical and experimental absorption electronic transitions were correlated by testing different functionals: B3LYP, CAM-B3LYP, PBE0, wB97XD, HSEH1PBE and M062X. Frontier molecular orbitals (FOMs) and molecular electrostatic potentials (MEPs) supported the ICT from the donor to the acceptor group. The global reactivity descriptors were studied and the NLO properties were predicted by calculating first (<em>β</em><sub><em>tot</em></sub>) and second-order (<em>γ</em><sub><em>ave</em></sub>) hyperpolarizabilities, revealing that <strong>7a-d</strong> would present promising NLO behavior.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

DFT calculations of properties of CF3-carbocations of the thiophene series as key intermediates in the synthesis of novel CF3-thiophenes 噻吩系列 CF3-配位物作为合成新型 CF3-噻吩的关键中间体的性质的 DFT 计算

IF 2.1 3区化学

Tetrahedron Pub Date : 2024-10-25 DOI: 10.1016/j.tet.2024.134321

引用次数: 0