Pub Date : 2025-12-13DOI: 10.1016/j.tetlet.2025.155920
Xuejiao Chen , Wenqing Luo , Zhibin Zhang , Yufeng Liu , Yalin Zhang , Guoping Yang
This study presents an efficient and environmentally benign protocol for the synthesis of quinazolinones via H3PW12O40-catalyzed cyclization of o-aminobenzamides with ortho esters under mild conditions. By employing H3PW12O40 as the catalyst and EtOH as the solvent, various o-aminobenzamides and ortho esters reacted efficiently to form quinazolinones up to 96 % yield. The advantages of this transformation include the use of a green catalyst and solvent, a broad substrate scope, high efficiency, and operational simplicity. This strategy would provide opportunities for the green synthesis of potential biologically active molecules.
{"title":"H3PW12O40-catalyzed cyclization of o-aminobenzamides with ortho esters for quinazolinones synthesis","authors":"Xuejiao Chen , Wenqing Luo , Zhibin Zhang , Yufeng Liu , Yalin Zhang , Guoping Yang","doi":"10.1016/j.tetlet.2025.155920","DOIUrl":"10.1016/j.tetlet.2025.155920","url":null,"abstract":"<div><div>This study presents an efficient and environmentally benign protocol for the synthesis of quinazolinones via H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub>-catalyzed cyclization of <em>o</em>-aminobenzamides with <em>ortho</em> esters under mild conditions. By employing H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub> as the catalyst and EtOH as the solvent, various <em>o</em>-aminobenzamides and <em>ortho</em> esters reacted efficiently to form quinazolinones up to 96 % yield. The advantages of this transformation include the use of a green catalyst and solvent, a broad substrate scope, high efficiency, and operational simplicity. This strategy would provide opportunities for the green synthesis of potential biologically active molecules.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155920"},"PeriodicalIF":1.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.tetlet.2025.155927
Kunal Madaan, Ram Singh
In this work, we have reported the synthesis of 3-hydroxy-3-acylisoinolin-1-ones from 2-(1-alkynyl)benzamides mediated by Selectfluor. This facile and novel methodology affords various 3-hydroxy-3-acylisoinolin-1-ones with yields of 73–85 % in 5 h. In this method, cyclization, oxidation, and hydroxylation of 2-(1-alkynyl)benzamides takes place in one pot single step. Control experiments were performed to understand and propose the mechanism of this novel synthetic route.
{"title":"Selectfluor-mediated regioselective synthesis of 3-Hydroxy-3-acylisoinolin-1-ones from 2-(1-alkynyl)benzamides","authors":"Kunal Madaan, Ram Singh","doi":"10.1016/j.tetlet.2025.155927","DOIUrl":"10.1016/j.tetlet.2025.155927","url":null,"abstract":"<div><div>In this work, we have reported the synthesis of 3-hydroxy-3-acylisoinolin-1-ones from 2-(1-alkynyl)benzamides mediated by Selectfluor. This facile and novel methodology affords various 3-hydroxy-3-acylisoinolin-1-ones with yields of 73–85 % in 5 h. In this method, cyclization, oxidation, and hydroxylation of 2-(1-alkynyl)benzamides takes place in one pot single step. Control experiments were performed to understand and propose the mechanism of this novel synthetic route.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155927"},"PeriodicalIF":1.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A general method for preparing spirocyclic/cyclic tetraarylmethanes through one-step cyclization of diaryl compounds (diaryl, diarylamine, diaryl ether, and diaryl thioether) with diarylketones using triflimide (HNTf₂) as a catalyst has been developed. The key step involves a Friedel-Crafts reaction. This straightforward synthetic approach features wide substrate scope, mild reaction conditions, a low catalyst amount, good yield, and allows the synthesis of unusual spirocyclic compounds that are otherwise difficult to achieve.
{"title":"A general cyclization strategy of diaryl, diarylamine, diaryl ether, and diaryl thioether with diarylketone: one-step synthesis of spirocyclic/ cyclic tetraarylmethanes","authors":"Shuangping Liao , Yeshen Liu , Bochao Jiang , Yufeng Hui, Haibo Xiao","doi":"10.1016/j.tetlet.2025.155929","DOIUrl":"10.1016/j.tetlet.2025.155929","url":null,"abstract":"<div><div>A general method for preparing spirocyclic/cyclic tetraarylmethanes through one-step cyclization of diaryl compounds (diaryl, diarylamine, diaryl ether, and diaryl thioether) with diarylketones using triflimide (HNTf₂) as a catalyst has been developed. The key step involves a Friedel-Crafts reaction. This straightforward synthetic approach features wide substrate scope, mild reaction conditions, a low catalyst amount, good yield, and allows the synthesis of unusual spirocyclic compounds that are otherwise difficult to achieve.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"176 ","pages":"Article 155929"},"PeriodicalIF":1.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145754031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A highly diastereoselective synthesis of 3-phthalimido-substituted cis-β-lactam through an ynimide-Kinugasa reaction is reported. This transformation is noteworthy because it offers straightforward access to 3-amino-substituted cis-β-lactams. These compounds are otherwise difficult to obtain: the ynamide–Kinugasa reaction requires harsh deprotection conditions, whereas the Staudinger ketene–imine cycloaddition predominantly furnishes trans-β-lactams.
{"title":"Regio- and stereoselective synthesis of cis-3-amino-β-lactams","authors":"Noriko Okamoto, Chie Nakamo, Keiji Konishi, Takuya Sueda","doi":"10.1016/j.tetlet.2025.155926","DOIUrl":"10.1016/j.tetlet.2025.155926","url":null,"abstract":"<div><div>A highly diastereoselective synthesis of 3-phthalimido-substituted <em>cis</em>-β-lactam through an ynimide-Kinugasa reaction is reported. This transformation is noteworthy because it offers straightforward access to 3-amino-substituted <em>cis</em>-β-lactams. These compounds are otherwise difficult to obtain: the ynamide–Kinugasa reaction requires harsh deprotection conditions, whereas the Staudinger ketene–imine cycloaddition predominantly furnishes <em>trans</em>-β-lactams.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155926"},"PeriodicalIF":1.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An unprecedented 1,6 conjugate addition of aza-nucleophile indoline to 4-nitro-5-styrylisoxazoles is reported. Selected adducts, which were obtained in high yields, were subsequently converted to the corresponding β-indolinecarboxylates via the hydrolysis of the 4-nitroisoxazole core. The synthetic methodology, herein described, provides access to indoline-beta carboxylic acids and their esters which synthesis has been rarely reported.
{"title":"The reaction of 4-nitro-5-styrylisoxazoles and indoline","authors":"Simone Bruschi , Lucio Leopaldi , Erica Paltrinieri , Mauro F.A. Adamo","doi":"10.1016/j.tetlet.2025.155925","DOIUrl":"10.1016/j.tetlet.2025.155925","url":null,"abstract":"<div><div>An unprecedented 1,6 conjugate addition of aza-nucleophile indoline to 4-nitro-5-styrylisoxazoles is reported. Selected adducts, which were obtained in high yields, were subsequently converted to the corresponding β-indolinecarboxylates via the hydrolysis of the 4-nitroisoxazole core. The synthetic methodology, herein described, provides access to indoline-beta carboxylic acids and their esters which synthesis has been rarely reported.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155925"},"PeriodicalIF":1.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-06DOI: 10.1016/j.tetlet.2025.155923
Bingbing Hou , Shengnan Zhang , Jiajing Su , Fangyi Gong , Wenke Sun , Longjun Ma , Hongxin Liu
Herein, we have developed a novel, environmentally friendly, straightforward, and practical methodology for the construction of 1,3-dihydroxy lactams incorporating multiple quaternary carbon centers through cascade reactions between ketoamides and acetyl compounds in aqueous media. Such molecular architectures are prevalent in natural product systems. This transformation constitutes the first reported instance of employing an amino acid salt to catalyze the formation of dihydroxy lactam-fused polycyclic quaternary carbon frameworks via a sequential aldol and azo-aldol addition cascade process in an aqueous environment. Notably, this reaction exhibits exceptional atom economy, facilitates gram-scale synthesis, and enables multiple catalytic turnovers, delivering the desired products in excellent yields and diastereoselectivities with convenient isolation via centrifugation.
{"title":"Aqueous-phase construction of dihydroxy lactam via cascade reaction catalyzed by amino acid salts","authors":"Bingbing Hou , Shengnan Zhang , Jiajing Su , Fangyi Gong , Wenke Sun , Longjun Ma , Hongxin Liu","doi":"10.1016/j.tetlet.2025.155923","DOIUrl":"10.1016/j.tetlet.2025.155923","url":null,"abstract":"<div><div>Herein, we have developed a novel, environmentally friendly, straightforward, and practical methodology for the construction of 1,3-dihydroxy lactams incorporating multiple quaternary carbon centers through cascade reactions between ketoamides and acetyl compounds in aqueous media. Such molecular architectures are prevalent in natural product systems. This transformation constitutes the first reported instance of employing an amino acid salt to catalyze the formation of dihydroxy lactam-fused polycyclic quaternary carbon frameworks <em>via</em> a sequential aldol and azo-aldol addition cascade process in an aqueous environment. Notably, this reaction exhibits exceptional atom economy, facilitates gram-scale synthesis, and enables multiple catalytic turnovers, delivering the desired products in excellent yields and diastereoselectivities with convenient isolation <em>via</em> centrifugation.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155923"},"PeriodicalIF":1.5,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.tetlet.2025.155922
Ravi Varala , Vittal Seema , Murali Mohan Achari Kamsali , Nahida Kousar , Mohamed Hussein , Mohammed Mujahid Alam
Heterocyclic compounds represent essential frameworks that are prevalent in nature and demonstrate intriguing biological and pharmaceutical properties. Quinoline and isoquinoline derived scaffolds represent a category of N-heterocyclic compounds that exhibit a wide array of biological properties. Reactions mediated by visible light have developed into a formidable instrument in organic synthesis over the last 15 years, transforming the methodologies employed by chemists in tackling complex bond-forming processes.
This review constitutes the most thorough examination to date of photochemical strategies for the synthesis of quinoline and isoquinoline derivatives, encompassing advancements in this domain from 2021 to the present. The organization is based on the categories of starting compounds, and it delves into synthetic strategies for the target compounds, accompanied by proposed reaction mechanisms. We anticipate that this compilation will inspire chemists to explore innovative, eco-conscious approaches for the synthesis of these and other biologically important nitrogen-rich heterocycles.
{"title":"Visible light-driven innovative approaches for the synthesis of quinoline and isoquinoline based heterocycles","authors":"Ravi Varala , Vittal Seema , Murali Mohan Achari Kamsali , Nahida Kousar , Mohamed Hussein , Mohammed Mujahid Alam","doi":"10.1016/j.tetlet.2025.155922","DOIUrl":"10.1016/j.tetlet.2025.155922","url":null,"abstract":"<div><div>Heterocyclic compounds represent essential frameworks that are prevalent in nature and demonstrate intriguing biological and pharmaceutical properties. Quinoline and isoquinoline derived scaffolds represent a category of <em>N</em>-heterocyclic compounds that exhibit a wide array of biological properties. Reactions mediated by visible light have developed into a formidable instrument in organic synthesis over the last 15 years, transforming the methodologies employed by chemists in tackling complex bond-forming processes.</div><div>This review constitutes the most thorough examination to date of photochemical strategies for the synthesis of quinoline and isoquinoline derivatives, encompassing advancements in this domain from 2021 to the present. The organization is based on the categories of starting compounds, and it delves into synthetic strategies for the target compounds, accompanied by proposed reaction mechanisms. We anticipate that this compilation will inspire chemists to explore innovative, eco-conscious approaches for the synthesis of these and other biologically important nitrogen-rich heterocycles.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155922"},"PeriodicalIF":1.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Urea-promoted, efficient and green methodology has been developed for the synthesis of a library of medicinally relevant 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) moieties using aromatic aldehydes and 3-methyl-1-phenyl-2-pyrazoline-5-one in good to excellent yield. This reaction displays broad functional group tolerance and affords a cost-effective, readily available, water-soluble and environmentally safe catalyst protocol for the quick synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) derivatives from readily available substrates. All the synthesized compounds were characterized by various analytical techniques such as FT-IR, 1H (Proton) NMR, 13C (Carbon) NMR analysis and high-resolution mass spectrometry.
{"title":"Urea-promoted simple and efficient synthesis of diverse and densely functionalized 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) in aqueous ethanol","authors":"Selvaraj Mangalaraj , Suresh Rajamanickam , Kavin Loganathan , Suhesh Aseervatham , Rashinikumar Samandram , Parthiban Anaikutti","doi":"10.1016/j.tetlet.2025.155921","DOIUrl":"10.1016/j.tetlet.2025.155921","url":null,"abstract":"<div><div>Urea-promoted, efficient and green methodology has been developed for the synthesis of a library of medicinally relevant 4,4′-(arylmethylene)bis(1<em>H</em>-pyrazol-5-ols) moieties using aromatic aldehydes and 3-methyl-1-phenyl-2-pyrazoline-5-one in good to excellent yield. This reaction displays broad functional group tolerance and affords a cost-effective, readily available, water-soluble and environmentally safe catalyst protocol for the quick synthesis of 4,4′-(arylmethylene)bis(1<em>H</em>-pyrazol-5-ols) derivatives from readily available substrates. All the synthesized compounds were characterized by various analytical techniques such as FT-IR, <sup>1</sup>H (Proton) NMR, <sup>13</sup>C (Carbon) NMR analysis and high-resolution mass spectrometry.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155921"},"PeriodicalIF":1.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.tetlet.2025.155919
Jannik Eckert, Lisa Marx, Tobias Sauter, Rafael Valentin, Andreas Speicher
Tetracyclic fused heterocycles of the aza-pterocarpen type are attracting increasing interest due to their various biological activities. We present a novel and straightforward synthesis of representative aza- and aza-carba-pterocarpens. For the first time, the Grignard-induced electrophilic amination of arene C−H bonds starting with o-nitrobiaryls was applied to this type of compound.
{"title":"Synthesis of aza- and aza-carba-pterocarpens by electrophilic amination of arene C−H bonds","authors":"Jannik Eckert, Lisa Marx, Tobias Sauter, Rafael Valentin, Andreas Speicher","doi":"10.1016/j.tetlet.2025.155919","DOIUrl":"10.1016/j.tetlet.2025.155919","url":null,"abstract":"<div><div>Tetracyclic fused heterocycles of the aza-pterocarpen type are attracting increasing interest due to their various biological activities. We present a novel and straightforward synthesis of representative aza- and aza-carba-pterocarpens. For the first time, the Grignard-induced electrophilic amination of arene C−H bonds starting with o-nitrobiaryls was applied to this type of compound.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155919"},"PeriodicalIF":1.5,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-29DOI: 10.1016/j.tetlet.2025.155910
Mengzhu Yu , Guangwei Yin , Yudi Hao , Xiaohui Yan , Fangyi Li
A new method has been developed for synthesizing 2,4-disubstituted oxazoles through base-promoted thermal cyclodebromination of β, β-dibrominated secondary enamides. This method does not require a transition metal or any external oxidants. Mechanistically, it is believed that the reaction is initiated by deprotonation of the secondary enamides, followed by a series of bond cleavage and formation events under thermal condition. Control experiments provided significant insights into the mechanism.
{"title":"Base-promoted thermal cyclodebromination of β, β-dibrominated secondary enamides to 2,4-disubstituted oxazoles","authors":"Mengzhu Yu , Guangwei Yin , Yudi Hao , Xiaohui Yan , Fangyi Li","doi":"10.1016/j.tetlet.2025.155910","DOIUrl":"10.1016/j.tetlet.2025.155910","url":null,"abstract":"<div><div>A new method has been developed for synthesizing 2,4-disubstituted oxazoles through base-promoted thermal cyclodebromination of β, β-dibrominated secondary enamides. This method does not require a transition metal or any external oxidants. Mechanistically, it is believed that the reaction is initiated by deprotonation of the secondary enamides, followed by a series of bond cleavage and formation events under thermal condition. Control experiments provided significant insights into the mechanism.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155910"},"PeriodicalIF":1.5,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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