In the present study, a three-phase system (EtOAc-water-EtOAc) for visible photocatalytic reduction of nitroaromatic compounds using β-CD-TiO2 was used. Also, for the first time, a comparison of water and magnetized water was investigated. Various factors such as amounts of TiO2, β-CD, PEG-400, light, time, and solvent were considered. Additionally, the phase-transfer catalytic character of β-CD- TiO2 was studied through transport tests. The UV–visible spectroscopic analysis supports higher solubility of nitroaromatic starting materials in magnetized water compared to deionized water. Analyses of the β-CD-TiO2 photocatalyst, including TEM, FESEM, EDAX-mapping, TGA, BET, DLS and ATR-FTIR were performed. Tuning of reaction conditions for obtaining valuable salicyl imine-based compounds in one-pot synthesis was performed. A practical scale of starting materials, short reaction time, fewer side reactions, simple separation of products and efficient one-pot synthesis of valuable salicyl imines are achievements of this three-phase system.
{"title":"A three phase photocatalytic system for practical one pot synthesis of salicyl imines from nitroaromatic compounds in magnetized water","authors":"Amir Farkhondeh , Foad Kazemi , Mostafa Gholizadeh , Babak Kaboudin","doi":"10.1016/j.tet.2026.135133","DOIUrl":"10.1016/j.tet.2026.135133","url":null,"abstract":"<div><div>In the present study, a three-phase system (EtOAc-water-EtOAc) for visible photocatalytic reduction of nitroaromatic compounds using β-CD-TiO<sub>2</sub> was used. Also, for the first time, a comparison of water and magnetized water was investigated. Various factors such as amounts of TiO<sub>2</sub>, β-CD, PEG-400, light, time, and solvent were considered. Additionally, the phase-transfer catalytic character of β-CD- TiO<sub>2</sub> was studied through transport tests. The UV–visible spectroscopic analysis supports higher solubility of nitroaromatic starting materials in magnetized water compared to deionized water. Analyses of the β-CD-TiO<sub>2</sub> photocatalyst, including TEM, FESEM, EDAX-mapping, TGA, BET, DLS and ATR-FTIR were performed. Tuning of reaction conditions for obtaining valuable salicyl imine-based compounds in one-pot synthesis was performed. A practical scale of starting materials, short reaction time, fewer side reactions, simple separation of products and efficient one-pot synthesis of valuable salicyl imines are achievements of this three-phase system.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135133"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922626","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}
Pub Date : 2026-05-01Epub Date: 2026-01-10DOI: 10.1016/j.tet.2026.135137
Junjie Wang , Wenhui Chen , Yue Zhang , Fenglan Xiong , Zhibin Chen , Jing Zhan , Xianrong Cai , Xiaoxue Yue , Xiaoyan Ma
N-Substituted cycloalkanes represent privileged scaffolds in numerous alkaloids and pharmacologically active molecules. However, synthetic access to these structures has been largely limited to monocyclic systems. In this work, the annulation of six kinds of enamides with an aromatic propargyl ester catalyzed by IPrAuCl/AgSbF6 was systematically investigated, with particular focus on the effects of electronic and structural attributes on the resulting cyclization modes, and [2 + 3] and [2 + 1] annulation products were successfully obtained in good yields.
n -取代环烷烃在许多生物碱和具有药理活性的分子中具有特殊的支架结构。然而，这些结构的合成途径在很大程度上仅限于单环系统。本文系统地研究了IPrAuCl/AgSbF6催化芳香族丙炔酯对六种酰胺的环化反应，重点研究了电子属性和结构属性对环化产物的影响，并成功地获得了产率较高的[2 + 3]和[2 + 1]环化产物。
{"title":"Annulation of diverse enamides with an aromatic propargyl ester","authors":"Junjie Wang , Wenhui Chen , Yue Zhang , Fenglan Xiong , Zhibin Chen , Jing Zhan , Xianrong Cai , Xiaoxue Yue , Xiaoyan Ma","doi":"10.1016/j.tet.2026.135137","DOIUrl":"10.1016/j.tet.2026.135137","url":null,"abstract":"<div><div>N-Substituted cycloalkanes represent privileged scaffolds in numerous alkaloids and pharmacologically active molecules. However, synthetic access to these structures has been largely limited to monocyclic systems. In this work, the annulation of six kinds of enamides with an aromatic propargyl ester catalyzed by IPrAuCl/AgSbF<sub>6</sub> was systematically investigated, with particular focus on the effects of electronic and structural attributes on the resulting cyclization modes, and [2 + 3] and [2 + 1] annulation products were successfully obtained in good yields.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135137"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974196","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}
Pub Date : 2026-05-01Epub Date: 2025-12-17DOI: 10.1016/j.tet.2025.135104
Sasha Hayes , Jonathan M. White , Bernd H.A. Rehm , Rohan A. Davis
Chemical investigations of the Australian marine sponge Ianthella basta resulted in the isolation of six known secondary metabolites, which included bastadins 4 (1), 5, (2) 8 (3) and 13 (4), 3,5-dibromo-4-methoxybenzeneacetic acid (5) and 3,5-dibromo-4-methoxybenzoic acid (6). The screening of these metabolites for inhibitory activity towards Pseudomonas aeruginosa (strain PAO1) for planktonic cell growth and biofilm formation identified metabolite 6 as a biofilm inhibitor. Based on these data a 13 membered semisynthetic amide library was generated using metabolite 6 as a scaffold for medicinal chemistry studies. Whilst none of the new semisynthetic compounds increased inhibitory activity towards PAO1 compared to the original scaffold, additional screening of the natural and semisynthetic library against the clinically relevant strain PDO300 showed that some of the secondary metabolites inhibited planktonic growth and biofilm formation. Furthermore, all semisynthetic compounds displayed increased inhibitory activity of planktonic growth with N,N'-((butane-1,4-diylbis(azanediyl))bis(propane-3,1-diyl))bis(3,5-dibromo-4-methoxybenzamide) (19) displaying 46 % planktonic inhibition and 3,5-dibromo-N-(4-fluorophenethyl)-4-methoxybenzamide (14) inhibiting biofilm formation by 21 % at 50 μM. All semisynthetic derivatives were obtained in yields ranging from 3 % to 79 %, and in purities >95 %. All new natural product derivatives were fully characterized following 1D/2D NMR, LRESIMS and HRESIMS data analysis; two semisynthetic compounds were crystalline, which enabled X-ray diffraction studies. The new chemistry and biology reported here indicate that the bastadin and 3,5-dibromo-4-methoxybenzoic acid motifs warrant further investigation against P. aeruginosa.
{"title":"Synthesis and antibacterial evaluation of a unique amide library based on the marine natural product 3,5-dibromo-4-methoxybenzoic acid","authors":"Sasha Hayes , Jonathan M. White , Bernd H.A. Rehm , Rohan A. Davis","doi":"10.1016/j.tet.2025.135104","DOIUrl":"10.1016/j.tet.2025.135104","url":null,"abstract":"<div><div>Chemical investigations of the Australian marine sponge <em>Ianthella basta</em> resulted in the isolation of six known secondary metabolites, which included bastadins 4 (<strong>1</strong>), 5, (<strong>2</strong>) 8 (<strong>3</strong>) and 13 (<strong>4</strong>), 3,5-dibromo-4-methoxybenzeneacetic acid (<strong>5</strong>) and 3,5-dibromo-4-methoxybenzoic acid (<strong>6</strong>). The screening of these metabolites for inhibitory activity towards <em>Pseudomonas aeruginosa</em> (strain PAO1) for planktonic cell growth and biofilm formation identified metabolite <strong>6</strong> as a biofilm inhibitor. Based on these data a 13 membered semisynthetic amide library was generated using metabolite <strong>6</strong> as a scaffold for medicinal chemistry studies. Whilst none of the new semisynthetic compounds increased inhibitory activity towards PAO1 compared to the original scaffold, additional screening of the natural and semisynthetic library against the clinically relevant strain PDO300 showed that some of the secondary metabolites inhibited planktonic growth and biofilm formation. Furthermore, all semisynthetic compounds displayed increased inhibitory activity of planktonic growth with <em>N,N'</em>-((butane-1,4-diylbis(azanediyl))bis(propane-3,1-diyl))bis(3,5-dibromo-4-methoxybenzamide) (<strong>19</strong>) displaying 46 % planktonic inhibition and 3,5-dibromo-<em>N</em>-(4-fluorophenethyl)-4-methoxybenzamide (<strong>14</strong>) inhibiting biofilm formation by 21 % at 50 μM. All semisynthetic derivatives were obtained in yields ranging from 3 % to 79 %, and in purities >95 %. All new natural product derivatives were fully characterized following 1D/2D NMR, LRESIMS and HRESIMS data analysis; two semisynthetic compounds were crystalline, which enabled X-ray diffraction studies. The new chemistry and biology reported here indicate that the bastadin and 3,5-dibromo-4-methoxybenzoic acid motifs warrant further investigation against <em>P. aeruginosa</em>.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135104"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145872720","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}
Pub Date : 2026-05-01Epub Date: 2026-01-11DOI: 10.1016/j.tet.2026.135136
Chao Yao , Yan Zhao , Yangyang Ou , Tengyang Zhang , Yue-Ming Li
Chiral copper complex bearing binaphthyl-prolinol-imidazoline type tridentate ligand was effective in enantioselective Friedel-Crafts alkylation of indoles with cyclic N-sulfonyl ketimino esters. The catalyst system exhibited excellent catalytic activity (up to 95 % yield) and enantioselectivity (up to 96 % ee), affording a series of chiral cyclic α-amino acid ester derivatives under mild reaction conditions. In addition to different indoles, the catalyst system was also compatible with pyrrole and 1-naphthol. The scalability of the reaction was exemplified with a gram-scale reaction. A plausible reaction mechanism was proposed based on preliminary DFT calculation results.
{"title":"Enantioselective Friedel-Crafts alkylation of indoles with cyclic N-sulfonyl ketimino esters catalyzed by Cu(II) complex bearing binaphthyl-proline-imidazoline-based ligands","authors":"Chao Yao , Yan Zhao , Yangyang Ou , Tengyang Zhang , Yue-Ming Li","doi":"10.1016/j.tet.2026.135136","DOIUrl":"10.1016/j.tet.2026.135136","url":null,"abstract":"<div><div>Chiral copper complex bearing binaphthyl-prolinol-imidazoline type tridentate ligand was effective in enantioselective Friedel-Crafts alkylation of indoles with cyclic <em>N</em>-sulfonyl ketimino esters. The catalyst system exhibited excellent catalytic activity (up to 95 % yield) and enantioselectivity (up to 96 % ee), affording a series of chiral cyclic α-amino acid ester derivatives under mild reaction conditions. In addition to different indoles, the catalyst system was also compatible with pyrrole and 1-naphthol. The scalability of the reaction was exemplified with a gram-scale reaction. A plausible reaction mechanism was proposed based on preliminary DFT calculation results.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135136"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023266","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}
Pub Date : 2026-05-01Epub Date: 2026-01-08DOI: 10.1016/j.tet.2026.135135
Jin-Qiu You , Yun-Qi Jin , Chun-Yang Zhang , Wei-Zhen Huang
Tinosagitines A (1) and B (2), two previously undescribed clerodane diterpenoids, were isolated from the rhizomes of Tinospora sagittata. Compound 1 is a rare 19-nor-clerodane diterpenoid featuring a 6/6-fused ring system, while compound 2 represents the first example of clerodane diterpenoid characterized by a unique trans-6/6-fused ring system with highly oxidization in Tinospora sagittata plants. Their structures were determined through comprehensive spectroscopic analysis, including NMR spectroscopy, HRESIMS, and electronic circular dichroism (ECD) calculations. The inhibitory activities on death-associated protein kinase-related apoptosis-inducing kinase 2 (DRAK2) were evaluated, but both of them were inactive.
{"title":"Tinosagitines A and B, two modified clerodane diterpenoids from the rhizomes of Tinospora sagittata","authors":"Jin-Qiu You , Yun-Qi Jin , Chun-Yang Zhang , Wei-Zhen Huang","doi":"10.1016/j.tet.2026.135135","DOIUrl":"10.1016/j.tet.2026.135135","url":null,"abstract":"<div><div>Tinosagitines A (<strong>1</strong>) and B (<strong>2</strong>), two previously undescribed clerodane diterpenoids, were isolated from the rhizomes of <em>Tinospora sagittata</em>. Compound <strong>1</strong> is a rare 19-nor-clerodane diterpenoid featuring a 6/6-fused ring system, while compound <strong>2</strong> represents the first example of clerodane diterpenoid characterized by a unique <em>trans-</em>6/6-fused ring system with highly oxidization in <em>Tinospora sagittata</em> plants. Their structures were determined through comprehensive spectroscopic analysis, including NMR spectroscopy, HRESIMS, and electronic circular dichroism (ECD) calculations. The inhibitory activities on death-associated protein kinase-related apoptosis-inducing kinase 2 (DRAK2) were evaluated, but both of them were inactive.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135135"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922628","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}
Pub Date : 2026-05-01Epub Date: 2026-01-21DOI: 10.1016/j.tet.2026.135150
Ligia Breda e Vasconcelos , Samuel Filipe Cardoso de Paula , Pedro Henrique de Oliveira Santiago , Javier Ellena , André Luiz Meleiro Porto
- In this work, the green synthesis method based on the bio-oxidation of progesterone was investigated using the mycelium of the marine-origin fungus, Penicillium oxalicum CBMAI 1996. The structural characterization of a novel minor product, 2β,15β-dihydroxyprogesterone (2β,15β-di-OH), was carried out using NMR techniques (1D, 1H and 13C; 2D, HSQC, HMBC, COSY, and NOESY), FTIR, and single crystal X-ray diffraction. The biotransformation reactions of progesterone to obtain the compound 2β,15β-di-OH were carried out in quintuplicate over 15 days (32 °C, 130 rpm, pH 7.4). Furthermore, the novel X-ray single crystal analyses of the major products, 15β-hydroxyprogesterone (15β-OH) and 7β,15β-dihydroxyprogesterone (7β,15β-di-OH), which were also previously isolated from the fungus P. oxalicum CBMAI 1996, unequivocally confirmed their structural formulas. It was also possible to determine from the X-ray analyses the absolute configuration of the hydroxylated chiral carbons, so the obtained values were 15R–OH, 7S,15R-di-OH, and 2S,15R-di-OH.
{"title":"A novel progesterone product obtained by biooxidation from marine-derivated fungus Penicillium oxalicum CBMAI 1996","authors":"Ligia Breda e Vasconcelos , Samuel Filipe Cardoso de Paula , Pedro Henrique de Oliveira Santiago , Javier Ellena , André Luiz Meleiro Porto","doi":"10.1016/j.tet.2026.135150","DOIUrl":"10.1016/j.tet.2026.135150","url":null,"abstract":"<div><div>- In this work, the green synthesis method based on the bio-oxidation of progesterone was investigated using the mycelium of the marine-origin fungus, <em>Penicillium oxalicum</em> CBMAI 1996. The structural characterization of a novel minor product, <strong>2β,15β-dihydroxyprogesterone</strong> (<strong>2β,15β-di-OH</strong>), was carried out using NMR techniques (1D, <sup>1</sup>H and <sup>13</sup>C; 2D, HSQC, HMBC, COSY, and NOESY), FTIR, and single crystal X-ray diffraction. The biotransformation reactions of progesterone to obtain the compound <strong>2β,15β-di-OH</strong> were carried out in quintuplicate over 15 days (32 °C, 130 rpm, pH 7.4). Furthermore, the novel X-ray single crystal analyses of the major products, <strong>15β-hydroxyprogesterone</strong> (<strong>15β-OH</strong>) and <strong>7β,15β-dihydroxyprogesterone</strong> (<strong>7β,15β-di-OH</strong>), which were also previously isolated from the fungus <em>P. oxalicum</em> CBMAI 1996, unequivocally confirmed their structural formulas. It was also possible to determine from the X-ray analyses the absolute configuration of the hydroxylated chiral carbons, so the obtained values were 15<em>R</em>–OH, 7<em>S</em>,15<em>R</em>-di-OH, and 2<em>S</em>,15<em>R</em>-di-OH.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135150"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073877","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}
Pub Date : 2026-05-01Epub Date: 2026-01-03DOI: 10.1016/j.tet.2025.135130
Valentina Birukova, Anatoly Y. Chursin, Igor V. Zavarzin, Yulia A. Volkova
A novel approach to the synthesis of 2-carboxamide-substituted benzimidazoles from a wide range of 1,2-diamines and 2-functionalized acetamides was developed via elemental sulfur promoted cascade reaction. This procedure provides an efficient and facile route to benzimidazoles from readily available substrates under mild reaction conditions. The protocol is distinguished by efficiency in water and good tolerance to functional groups.
{"title":"Synthesis of 2-carboxamide-substituted benzimidazoles via S8-promoted multicomponent reaction in aqueous media","authors":"Valentina Birukova, Anatoly Y. Chursin, Igor V. Zavarzin, Yulia A. Volkova","doi":"10.1016/j.tet.2025.135130","DOIUrl":"10.1016/j.tet.2025.135130","url":null,"abstract":"<div><div>A novel approach to the synthesis of 2-carboxamide-substituted benzimidazoles from a wide range of 1,2-diamines and 2-functionalized acetamides was developed <em>via</em> elemental sulfur promoted cascade reaction. This procedure provides an efficient and facile route to benzimidazoles from readily available substrates under mild reaction conditions. The protocol is distinguished by efficiency in water and good tolerance to functional groups.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135130"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974197","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}
Pub Date : 2026-05-01Epub Date: 2026-01-11DOI: 10.1016/j.tet.2026.135139
Qing-Miao Pu , Xue Ran , Si-Wei Chen , Ke-Jin Jiao , Xiao-Tong Gao
Sulfoximines represent a privileged structural motif in pharmaceuticals, agrochemicals, and materials science. The electrochemical transformation of sulfoximines has garnered considerable interest among chemists, as electrons serve as clean, sustainable, and traceless reagents to drive these reactions. With the resurgence of electrochemical synthesis, many innovative and intriguing strategies have been developed for the synthesis of structurally diverse sulfoximines. This review systematically summarizes recent advances in this field according to the type of bond formed, including N–C, N–S, and N–P bonds. By highlighting representative examples and mechanistic insights, we aim to outline current trends and future challenges in this emerging area.
{"title":"Recent advances in electrochemical transformation of sulfoximines","authors":"Qing-Miao Pu , Xue Ran , Si-Wei Chen , Ke-Jin Jiao , Xiao-Tong Gao","doi":"10.1016/j.tet.2026.135139","DOIUrl":"10.1016/j.tet.2026.135139","url":null,"abstract":"<div><div>Sulfoximines represent a privileged structural motif in pharmaceuticals, agrochemicals, and materials science. The electrochemical transformation of sulfoximines has garnered considerable interest among chemists, as electrons serve as clean, sustainable, and traceless reagents to drive these reactions. With the resurgence of electrochemical synthesis, many innovative and intriguing strategies have been developed for the synthesis of structurally diverse sulfoximines. This review systematically summarizes recent advances in this field according to the type of bond formed, including N–C, N–S, and N–P bonds. By highlighting representative examples and mechanistic insights, we aim to outline current trends and future challenges in this emerging area.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135139"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974194","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}
A Palladium-catalyzed site-selective difluoroalkylation of 8-aminoquinoline amides has been described. This approach enables the efficient synthesis of C5-difluoroalkylated products from a broad range of 8-aminoquinoline amides under mild conditions, exhibiting excellent functional group tolerance. Preliminary mechanistic studies suggest that the reaction involves a free radical pathway. This strategy offers a new and practical for the synthesis of difluoroalkylation heterocycles.
{"title":"Palladium-catalyzed remote selective C5–H difluoroalkylation of 8-aminoquinoline amides with triethoxysilane as reductant","authors":"Weiwei Lv, Hao Luo, Qiaoyun Li, Wanying Yang, Yijing Chen, Xueting Zhu, Huihui Chen, Jiaxu Li","doi":"10.1016/j.tet.2026.135131","DOIUrl":"10.1016/j.tet.2026.135131","url":null,"abstract":"<div><div>A Palladium-catalyzed site-selective difluoroalkylation of 8-aminoquinoline amides has been described. This approach enables the efficient synthesis of C5-difluoroalkylated products from a broad range of 8-aminoquinoline amides under mild conditions, exhibiting excellent functional group tolerance. Preliminary mechanistic studies suggest that the reaction involves a free radical pathway. This strategy offers a new and practical for the synthesis of difluoroalkylation heterocycles.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135131"},"PeriodicalIF":2.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922627","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}
Pub Date : 2026-05-01Epub Date: 2026-01-17DOI: 10.1016/j.tet.2026.135153
Sofia Kolyadina, Andrey Kruchinin, Mikhail Minyaev, Maxim Bastrakov, Alexey Starosotnikov
A number of novel 2-R-6-nitro[1,2,4]triazolo[1,5-a]pyrimidines were synthesized. Their reactions with neutral C-nucleophiles (1,3-dicarbonyl compounds, indoles, polyphenols) proceeded under mild conditions (room temperature, no base or catalyst) giving rise to stable 1,4-adducts to pyrimidine ring. On the basis of 7-amino-6-nitro[1,2,4]triazolo[1,5-a]pyrimidines, a method was developed for the preparation of the previously unknown heterocyclic systems, namely [1,2,4]triazolo[1,5-a]pyrimidines fused with 1,2,5-oxa-, thia- and selenadiazole rings. These new heterocycles were found to undergo facile dearomatization under the action of 1,3-dicarbonyl compounds and π-excessive (het)arenes to give 1,2-adducts to pyrimidine ring. The possibility of oxidative rearomatization of the obtained adducts under the action of DDQ was demonstrated.
合成了一些新型的2- r -6-硝基[1,2,4]三唑[1,5- A]嘧啶。它们与中性c -亲核试剂（1,3-二羰基化合物、吲哚、多酚）在温和条件下（室温、无碱或催化剂）反应，生成稳定的1,4-嘧啶环加合物。在7-氨基-6-硝基[1,2,4]三唑[1,5-a]嘧啶的基础上，开发了一种制备先前未知的杂环体系的方法，即[1,2,4]三唑[1,5-a]嘧啶与1,2,5-氧-、西亚-和硒二唑环融合。这些新杂环在1,3-二羰基化合物和π-过量（羟基）芳烃的作用下易发生脱芳反应，使1,2-加合物生成嘧啶环。结果表明，所得加合物在DDQ的作用下可能发生氧化重芳构化反应。
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