Tetrahedron最新文献

{"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":"Kamlesh Saini,&nbsp;Ashok K. Raigar,&nbsp;Manju,&nbsp;Nirmal Jyoti,&nbsp;Anjali Guleria","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":"168 ","pages":"Article 134346"},"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}

{"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":"Julio C. Flores-Reyes ,&nbsp;Alejandro Valderrama-Celestino ,&nbsp;María F. Trejo-Velasco ,&nbsp;Karla I. Jaramillo-Márquez ,&nbsp;Federico González ,&nbsp;Alberto Rojas-Hernández ,&nbsp;Annia Galano ,&nbsp;Alejandro Islas-Jácome ,&nbsp;Eduardo González-Zamora","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":"168 ","pages":"Article 134335"},"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}

{"title":"Advancements in the selective transformation of olefins to new C–C bonds through cooperative catalysis involving electrochemistry and transition metals","authors":"ChunXiao Nong,&nbsp;Yi Jin","doi":"10.1016/j.tet.2024.134330","DOIUrl":"10.1016/j.tet.2024.134330","url":null,"abstract":"<div><div>This article aims to comprehensively review the research progress in the selective C–C bond formation of olefins through the synergistic action of electrochemistry and transition metal catalysis in recent years, particularly since 2018. Specifically, we will focus on how the combined catalysis of electrochemistry and transition metals achieves precise control over chemical, stereoselective, and regioselective outcomes, and delve deeply into the underlying reaction mechanisms. By summarizing key scientific discoveries and technological breakthroughs, this article aims to provide a reference guide for researchers in related fields and offer insights into future trends and potential applications in this domain.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134330"},"PeriodicalIF":2.1,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561192","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}

{"title":"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","authors":"Atul R. Pandavadara,&nbsp;Aditya N. Khanvilkar,&nbsp;Ashutosh V. Bedekar","doi":"10.1016/j.tet.2024.134326","DOIUrl":"10.1016/j.tet.2024.134326","url":null,"abstract":"<div><div>In the present work, <em>trans</em>-2-(3,5-dimethylphenoxy)cyclohexan-1-ol was synthesized and its enantiomers were separated by Enzymatic Kinetic Resolution (EKR). The absolute configuration was established by converting to diastereomer with esters of known chiral description. Chiral alcohol was then used as an auxiliary for the preparation of esters by coupling with racemic α-halo acids in presence of DCC and a suitable base. We observed an efficient Dynamic Kinetic Resolution as the product esters were obtained in enriched diastereomeric forms. Effect of several parameters like base, temperature and reaction time was studied. The relative energy profile of the diastereomers was studied by computational analysis and the energy difference of diastereomeric products were in accordance with the observed diastereoselectivity. The chirally pure α-halo acid could be separated from the auxiliary, without any loss of optical purity of both components.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134326"},"PeriodicalIF":2.1,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578728","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}

{"title":"A short approach to cytogenin and first total synthesis of aspergisocoumarin A and fusarimarin C","authors":"Goreti Rajendar,&nbsp;Mintu Rehman","doi":"10.1016/j.tet.2024.134343","DOIUrl":"10.1016/j.tet.2024.134343","url":null,"abstract":"<div><div>A novel, efficient route to the first total synthesis of the bioactive isocoumarins aspergisocoumarin A, fusarimarin C and cytogenin is demonstrated. This approach features a groundbreaking single-step synthesis of isocoumarins utilizing a challenging cross-ester coupling of ethyl dimethoxy orsellinate and ethyl glycolate in the presence of a LiBr-LiTMP complex. The process leverages bromide ion-induced aggregation to facilitate a one-pot tandem reaction sequence: lateral lithiation, acylation, enolization, and lactonization. This innovative method directly produces the isocoumarin moiety with high efficiency. Subsequent transformations include selective BBr₃-mediated demethylation, oxidation, and Wittig reactions. The streamlined synthetic routes demonstrated: a two-step pathway to cytogenin and a four-step sequence to aspergisocoumarin A and fusarimarin C, achieving overall yields of 37 %, 27 %, and 27 % respectively.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134343"},"PeriodicalIF":2.1,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555676","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}

{"title":"A classical peptide coupling approach for the total synthesis of simnotrelvir","authors":"Siva Ramakrishna Paipuri ,&nbsp;Srihari Pabbaraja","doi":"10.1016/j.tet.2024.134342","DOIUrl":"10.1016/j.tet.2024.134342","url":null,"abstract":"<div><div>The total synthesis of an oral small-molecule antiviral agent; a structure based developmental drug simnotrelvir has been accomplished. The synthesis involves readily accessible commercial amino acids L-tert-leucine, 4-hydroxy-<span>l</span>-proline and <span>l</span>-glutamic acid that are easily converted to the key intermediates and are coupled together following classical peptide coupling technique using HATU and NMM. One of the crucial step in the synthesis involved a one pot Boc-deprotection and trifluoroacetylation of tert-leucine amino acid moiety mediated by ZnCl₂.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134342"},"PeriodicalIF":2.1,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572172","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}

{"title":"Facile synthesis of spiro-heterocycles through one-pot multicomponent [3 + 3] cross 1,3-dipolar cycloaddition reactions","authors":"Guo-Yang Ma ,&nbsp;Ya-Fei Li ,&nbsp;Qing Xu ,&nbsp;Yue-Yao Ma ,&nbsp;Ya-Wen Li ,&nbsp;Guo-Qiang Gong ,&nbsp;Ning Zhang ,&nbsp;Tan Dang ,&nbsp;Kai-Kai Wang","doi":"10.1016/j.tet.2024.134328","DOIUrl":"10.1016/j.tet.2024.134328","url":null,"abstract":"<div><div>A three-component 1,3-dipolar cycloaddition reaction involving ninhydrin, proline, and nitrile imines, which are generated in situ from hydrazonoyl chlorides, has been developed. This transformation can be conceptualized as a cross-1,3-dipolar cycloaddition reaction between two distinct ylides, proceeding via a [3 + 3] annulation pathway. This approach offers a swift route to a diverse array of novel and structurally intricate spiro-multiheterocyclic skeletons, achieving good yields ranging from 80 % to 94 %. Furthermore, the chemical structure of a representative product has been rigorously confirmed via X-ray diffraction analysis.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134328"},"PeriodicalIF":2.1,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533200","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}

{"title":"PPh3 promoted stereospecific synthesis of ethyl α-chloroacrylates from ethyl trichloroacetate and arylaldehydes","authors":"Axel Pliego-Santillan ,&nbsp;Ulises J. Vargas-Cruz ,&nbsp;Salvador Mastachi-Loza ,&nbsp;Misael A. Romero-Reyes ,&nbsp;Diego Martínez-Otero ,&nbsp;Moisés Romero-Ortega","doi":"10.1016/j.tet.2024.134341","DOIUrl":"10.1016/j.tet.2024.134341","url":null,"abstract":"<div><div>A coupling reaction between arylaldehydes and ethyl trichloroacetate is facilitated by PPh₃ under mild conditions to stereospecifically produce (Z)-ethyl α-chloroacrylates. This stereospecific coupling reaction only occurs when the arylaldehyde derivative has an electron-withdrawing substituent. On the other hand, when an electron-donating group is present in the aromatic ring, the aryldichloromethyl derivative is formed as the only product, even at low temperature. The stereospecificity in the coupling reaction was established based on the coupling constants ²J_CH and ³<em>J</em>_CH in the ¹³C NMR and crystal-X-ray analysis. From this data we propose that the formation of these compounds occurs through two intermediates initially formed by the reaction between the PPh₃ and ethyl trichloroacetate.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134341"},"PeriodicalIF":2.1,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555674","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}

{"title":"Tuning the photophysical and NLO properties of β-diketonates derived from coumarin-triphenylamine-chalcones: Effect of the BF2 group","authors":"Edgard Fabián Blanco-Acuña ,&nbsp;Iván Alessandro Texon-García ,&nbsp;Luis Antonio Vázquez-López ,&nbsp;Alfredo Pérez-Gamboa ,&nbsp;Héctor García-Ortega","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 (BF₂) 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/H₂O 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 S₀ and the first excited state S₁ 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>_<em>tot</em>) and second-order (<em>γ</em>_<em>ave</em>) hyperpolarizabilities, revealing that <strong>7a-d</strong> would present promising NLO behavior.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134338"},"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}

{"title":"DFT calculations of properties of CF3-carbocations of the thiophene series as key intermediates in the synthesis of novel CF3-thiophenes","authors":"Olesya V. Khoroshilova ,&nbsp;Irina A. Boyarskaya ,&nbsp;Aleksander V. Vasilyev","doi":"10.1016/j.tet.2024.134321","DOIUrl":"10.1016/j.tet.2024.134321","url":null,"abstract":"<div><div>Trimethylsilyl ethers of thiophen-2-yl-(trifluoromethyl)methanols undergo multichannel electrophilic transformations under the action of Brønsted superacid acid CF₃SO₃H to form a wide range of CF₃-substituted thiophene structures. The key cationic intermediates of these transformations are CF₃-carbocations. Electronic and orbital characteristics, global electrophilicity indices, and thermodynamic characteristics of these key intermediates have been calculated with a use of the density functional theory (DFT). Experimental data on the reactivity of intermediate cationic species have been explained on the basis of the results of quantum chemical calculations. It has been shown that reactions of the cations with aromatic nucleophiles are mainly ruled by orbital control.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"168 ","pages":"Article 134321"},"PeriodicalIF":2.1,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552018","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}