Pub Date : 2025-11-03DOI: 10.1016/j.tet.2025.135031
Yingxin Qu , Wenli Jiang , Yaodong Ning, Yao Xu, Yihao Song, Ran Chen, Yeqin Fu, Jie Wang, Haobing Yu, Xiaoling Lu
Marine fungi hold immense research significance, acting as a treasure trove capable of generating complex chemical architectures and a diverse array of biologically active secondary metabolites. Talaromyces sp.6B3 was isolated from marine, and six compounds were extracted from its fermentation broth. Structural characterization of these compounds was accomplished using NMR spectroscopy, mass spectrometry, and circular dichroism spectroscopic analyses. Compounds 1–5 are novel entities within this series, whereas compounds 1, 2, and 6 are classified as furanone derivatives. Compounds 1 and 4 demonstrated inhibitory activity against Staphylococcus aureus, with a MIC of 25 μg/mL. Compound 1 exhibited a modest inhibitory effect against both A549 and H460 cancer cell, whereas compound 4 demonstrated a modest inhibitory effect against the H460 cell.
{"title":"Talapolyketide A-E, polyketone derivatives from the marine-derived fungus Talaromyces sp. 6B3","authors":"Yingxin Qu , Wenli Jiang , Yaodong Ning, Yao Xu, Yihao Song, Ran Chen, Yeqin Fu, Jie Wang, Haobing Yu, Xiaoling Lu","doi":"10.1016/j.tet.2025.135031","DOIUrl":"10.1016/j.tet.2025.135031","url":null,"abstract":"<div><div>Marine fungi hold immense research significance, acting as a treasure trove capable of generating complex chemical architectures and a diverse array of biologically active secondary metabolites. <em>Talaromyces</em> sp.6B3 was isolated from marine, and six compounds were extracted from its fermentation broth. Structural characterization of these compounds was accomplished using NMR spectroscopy, mass spectrometry, and circular dichroism spectroscopic analyses. Compounds 1–5 are novel entities within this series, whereas compounds 1, 2, and 6 are classified as furanone derivatives. Compounds 1 and 4 demonstrated inhibitory activity against <em>Staphylococcus aureus</em>, with a MIC of 25 μg/mL. Compound 1 exhibited a modest inhibitory effect against both A549 and H460 cancer cell, whereas compound 4 demonstrated a modest inhibitory effect against the H460 cell.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135031"},"PeriodicalIF":2.2,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475108","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 : 2025-11-02DOI: 10.1016/j.tet.2025.135030
Yuan Li , Xin-Yun Zhong , Guo-Dong Zhu , Zhi-Yang Zhou , Min Shen , Yong Peng , Xiang-Jun Peng
Direct α-amino C–H bond alkylation protocol holds paramount importance in the synthetic chemistry. Herein, we develope a metal-free and visible-light-induced α-C(sp3)−C(sp3) aminoalkylation of biologically important, dihydroquinoxalin-2(1H)-one moieties. The key to the success is formed the photoactivated electron donor-acceptor complex between quinoxalin-2(1H)-ones and tertiary amines, which undergo subsequent single-electron transfer to effect the desired C3 α-aminoalkylated dihydroquinoxalin-2(1H)-ones. This strategy offers efficient advancements to mild reaction conditions and high atom economy. In vitro antitumor studies, complex 3m participates on the apoptosis of human gastric adenocarcinoma cells, increasing to 29.4 % (30 μM).
{"title":"The C–H aminoalkylation of quinoxalin-2(1H)-ones with tertiary amines via electron donor−acceptor photoactivation","authors":"Yuan Li , Xin-Yun Zhong , Guo-Dong Zhu , Zhi-Yang Zhou , Min Shen , Yong Peng , Xiang-Jun Peng","doi":"10.1016/j.tet.2025.135030","DOIUrl":"10.1016/j.tet.2025.135030","url":null,"abstract":"<div><div>Direct α-amino C–H bond alkylation protocol holds paramount importance in the synthetic chemistry. Herein, we develope a metal-free and visible-light-induced α-C(<em>sp</em><sup><em>3</em></sup>)−C(<em>sp</em><sup><em>3</em></sup>) aminoalkylation of biologically important, dihydroquinoxalin-2(1<em>H</em>)-one moieties. The key to the success is formed the photoactivated electron donor-acceptor complex between quinoxalin-2(1<em>H</em>)-ones and tertiary amines, which undergo subsequent single-electron transfer to effect the desired C3 α-aminoalkylated dihydroquinoxalin-2(1<em>H</em>)-ones. This strategy offers efficient advancements to mild reaction conditions and high atom economy. <em>In vitro</em> antitumor studies, complex <strong>3m</strong> participates on the apoptosis of human gastric adenocarcinoma cells, increasing to 29.4 % (30 μM).</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135030"},"PeriodicalIF":2.2,"publicationDate":"2025-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475099","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 novel dual-target colorimetric and fluorescent chemosensor (NSN), incorporating a triphenylamine core, was developed for the simultaneous detection of Cu2+ and Ag + ions. NSN exhibited outstanding specificity and selectivity toward both analytes, with remarkably low detection limits (LODs) of 25.8 nM for Cu2+ and 51.3 nM for Ag+. Upon complexation with either metal ion, NSN underwent a rapid (<1 min) color change accompanied by pronounced fluorescence quenching, attributed to a chelation-enhanced quenching (CHEQ) effect. Theoretical calculations combined with experimental studies revealed a 1:1 binding stoichiometry of NSN to both Cu2+ and Ag + through nitrogen coordination. Reversibility assays using Ag+ and S2O32− not only demonstrated the chemical reversibility of the sensing process but also enabled the differentiation between Cu2+ and Ag+. Furthermore, NSN achieved high recovery rates in spiked real water samples, underscoring its practical applicability. Notably, NSN-functionalized test strips provided precise, rapid and naked-eye detection of Cu2+/Ag+ ions in complex environmental settings.
{"title":"A triphenylamine-derived fluorescence probe for specific detection of Cu2+ and Ag+ ions","authors":"Chongyao Liang , Wenlong Qin , Shengze Wang, Haiyan Xu","doi":"10.1016/j.tet.2025.135040","DOIUrl":"10.1016/j.tet.2025.135040","url":null,"abstract":"<div><div>A novel dual-target colorimetric and fluorescent chemosensor (<strong>NSN</strong>), incorporating a triphenylamine core, was developed for the simultaneous detection of Cu<sup>2+</sup> and Ag <sup>+</sup> ions. <strong>NSN</strong> exhibited outstanding specificity and selectivity toward both analytes, with remarkably low detection limits (LODs) of 25.8 nM for Cu<sup>2+</sup> and 51.3 nM for Ag<sup>+</sup>. Upon complexation with either metal ion, <strong>NSN</strong> underwent a rapid (<1 min) color change accompanied by pronounced fluorescence quenching, attributed to a chelation-enhanced quenching (CHEQ) effect. Theoretical calculations combined with experimental studies revealed a 1:1 binding stoichiometry of <strong>NSN</strong> to both Cu<sup>2+</sup> and Ag <sup>+</sup> through nitrogen coordination. Reversibility assays using Ag<sup>+</sup> and S<sub>2</sub>O<sub>3</sub><sup>2−</sup> not only demonstrated the chemical reversibility of the sensing process but also enabled the differentiation between Cu<sup>2+</sup> and Ag<sup>+</sup>. Furthermore, <strong>NSN</strong> achieved high recovery rates in spiked real water samples, underscoring its practical applicability. Notably, <strong>NSN</strong>-functionalized test strips provided precise, rapid and naked-eye detection of Cu<sup>2+</sup>/Ag<sup>+</sup> ions in complex environmental settings.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135040"},"PeriodicalIF":2.2,"publicationDate":"2025-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475100","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 : 2025-11-01DOI: 10.1016/j.tet.2025.135038
B. Berezhnoi, E. Chernoburova, I. Zavarzin, Y. Volkova
Naphthoxazole is a polycyclic heteroaromatic scaffold commonly found in bioactive molecules and natural products. However, effective and straightforward approaches to 2-amino substituted naphthoxazole remain challenging. We report here base-promoted cyclization of 1-nitroso-2-naphthol with isothiocyanates as a novel strategy for construction of 2-amino-substituted naphtho[1,2-d][1,3]oxazoles. The described method features short reaction time, the ability to scale up to gram-scale, good functional group tolerance, and readily available starting materials.
{"title":"Construction of 2-naphtho[1,2-d][1,3]oxazoles via base-promoted reaction of 1-nitroso-2-naphthol with isothiocyanates","authors":"B. Berezhnoi, E. Chernoburova, I. Zavarzin, Y. Volkova","doi":"10.1016/j.tet.2025.135038","DOIUrl":"10.1016/j.tet.2025.135038","url":null,"abstract":"<div><div>Naphthoxazole is a polycyclic heteroaromatic scaffold commonly found in bioactive molecules and natural products. However, effective and straightforward approaches to 2-amino substituted naphthoxazole remain challenging. We report here base-promoted cyclization of 1-nitroso-2-naphthol with isothiocyanates as a novel strategy for construction of 2-amino-substituted naphtho[1,2-<em>d</em>][1,3]oxazoles. The described method features short reaction time, the ability to scale up to gram-scale, good functional group tolerance, and readily available starting materials.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135038"},"PeriodicalIF":2.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577161","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 : 2025-11-01DOI: 10.1016/j.tet.2025.135032
Qiangqiang Shi , Han Wu , Kanghong Zhao , Huilan Yue
Nine novel limonoids, ciliatones M−U (1, 3–9, and 11), and two known analogues (2 and 10) were isolated from the branches and leaves of Toona ciliata M. Roem (Meliaceae). Their structures were elucidated through comprehensive spectroscopic data analysis combined with quantum chemistry calculations of NMR and ECD. Notably, compound 1 was the first limonoid found to possess a 14,15-dihydroxy motif, whereas a 14,15-epoxy group was more commonly encountered at this position; meanwhile, compounds 3–5 were characterized by a rare 8,14-epoxy bridge. Bioassessment revealed that compound 10 exhibited modest inhibitory activity against NO production in RAW264.7 cells, with an IC50 value of 33 μM. Western blot analysis indicated that compound 10 inhibited the phosphorylation of key proteins in the AKT/ERK/JNK signaling pathway.
从香椿ciliata M. Roem （Meliaceae）的枝叶中分离到9个新的柠檬素，ciliatones M−U（1,3 - 9,11）和2个已知的类似物（2和10）。通过全面的光谱数据分析，结合核磁共振和ECD的量子化学计算，对它们的结构进行了鉴定。值得注意的是，化合物1是第一个发现具有14,15-二羟基基序的柠檬类化合物，而14,15-环氧基在该位置更常见；同时，化合物3-5具有罕见的8,14-环氧桥。生物评价结果表明，化合物10对RAW264.7细胞的NO生成具有一定的抑制作用，IC50值为33 μM。Western blot分析表明，化合物10抑制AKT/ERK/JNK信号通路关键蛋白的磷酸化。
{"title":"Ciliatones M-U: Characterization of limonoid constituents from Toona ciliata","authors":"Qiangqiang Shi , Han Wu , Kanghong Zhao , Huilan Yue","doi":"10.1016/j.tet.2025.135032","DOIUrl":"10.1016/j.tet.2025.135032","url":null,"abstract":"<div><div>Nine novel limonoids, ciliatones M−U (<strong>1</strong>, <strong>3–9</strong>, and <strong>11</strong>), and two known analogues (<strong>2</strong> and <strong>10</strong>) were isolated from the branches and leaves of <em>Toona ciliata</em> M. Roem (Meliaceae). Their structures were elucidated through comprehensive spectroscopic data analysis combined with quantum chemistry calculations of NMR and ECD. Notably, compound <strong>1</strong> was the first limonoid found to possess a 14,15-dihydroxy motif, whereas a 14,15-epoxy group was more commonly encountered at this position; meanwhile, compounds <strong>3</strong>–<strong>5</strong> were characterized by a rare 8,14-epoxy bridge. Bioassessment revealed that compound <strong>10</strong> exhibited modest inhibitory activity against NO production in RAW264.7 cells, with an IC<sub>50</sub> value of 33 μM. Western blot analysis indicated that compound <strong>10</strong> inhibited the phosphorylation of key proteins in the AKT/ERK/JNK signaling pathway.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135032"},"PeriodicalIF":2.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475101","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 : 2025-10-31DOI: 10.1016/j.tet.2025.135036
Quanlin Wu , Can Yang , Xinying Man , Xin Li , Quansen Wu , Yijing Zhang , Dongfang Jiang , Zhenjie Qi
A novel Cu(OAc)2-catalyzed tandem cyclization/addition strategy has been developed for the synthesis of pyrazoline substituted oxime ethers from β,γ-unsaturated hydrazones and oximes using K2S2O8 as an oxidant and NaHCO3 as a base has been achieved. The reaction demonstrates broad substrate scope, tolerating aryl, heteroaryl, alkyl, and sulfonyl substituents on both hydrazones and oximes, and provides the products in up to 78 % yield. Mechanistic studies suggest the involvement of both energy transfer and single electron transfer processes in accomplishing the radical 5-exo-trig cyclization to the CN bond. Furthermore, scale-up experiment was also enabled.
{"title":"Cu(OAc)2/K2S2O8 promoted aminooximation of β,γ-unsaturated hydrazones to access pyrazoline substituted oxime ethers","authors":"Quanlin Wu , Can Yang , Xinying Man , Xin Li , Quansen Wu , Yijing Zhang , Dongfang Jiang , Zhenjie Qi","doi":"10.1016/j.tet.2025.135036","DOIUrl":"10.1016/j.tet.2025.135036","url":null,"abstract":"<div><div>A novel Cu(OAc)<sub>2</sub>-catalyzed tandem cyclization/addition strategy has been developed for the synthesis of pyrazoline substituted oxime ethers from <em>β</em>,<em>γ</em>-unsaturated hydrazones and oximes using K<sub>2</sub>S<sub>2</sub>O<sub>8</sub> as an oxidant and NaHCO<sub>3</sub> as a base has been achieved. The reaction demonstrates broad substrate scope, tolerating aryl, heteroaryl, alkyl, and sulfonyl substituents on both hydrazones and oximes, and provides the products in up to 78 % yield. Mechanistic studies suggest the involvement of both energy transfer and single electron transfer processes in accomplishing the radical 5-<em>exo</em>-trig cyclization to the C<img>N bond. Furthermore, scale-up experiment was also enabled.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135036"},"PeriodicalIF":2.2,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475158","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 : 2025-10-31DOI: 10.1016/j.tet.2025.135037
Feifei Wen , Xuyang Zhao , Xueqin Song , Huan Ma , Chengwang Wang , Yu Zhang , Pan Xie
A novel synergistic photoredox/palladium catalytic system has been developed for the visible light-induced decarboxylative benzoylation of arylpyridines using α-oxocarboxylic acids. This method proceeds efficiently at ambient temperature under aerobic conditions, employing Eosin Y as the photocatalyst, a Pd(II) complex as the transition metal catalyst, and K2S2O8 as the oxidant. A broad substrate scope, encompassing electron-donating and electron-withdrawing groups as well as diverse heterocyclic acids, afforded the corresponding benzoyl-substituted heteroarenes in moderate to good yields. This protocol offers an economical, mild, and sustainable strategy for the synthesis of valuable aromatic ketones, thereby advancing the field of dual photoredox/palladium catalysis.
{"title":"Visible light-induced synergistic photoredox/palladium catalysis for decarboxylative benzoylation of aryl pyridines: Efficient access to pyridine-substituted aryl ketones at ambient temperature","authors":"Feifei Wen , Xuyang Zhao , Xueqin Song , Huan Ma , Chengwang Wang , Yu Zhang , Pan Xie","doi":"10.1016/j.tet.2025.135037","DOIUrl":"10.1016/j.tet.2025.135037","url":null,"abstract":"<div><div>A novel synergistic photoredox/palladium catalytic system has been developed for the visible light-induced decarboxylative benzoylation of arylpyridines using <em>α</em>-oxocarboxylic acids. This method proceeds efficiently at ambient temperature under aerobic conditions, employing Eosin Y as the photocatalyst, a Pd(II) complex as the transition metal catalyst, and K<sub>2</sub>S<sub>2</sub>O<sub>8</sub> as the oxidant. A broad substrate scope, encompassing electron-donating and electron-withdrawing groups as well as diverse heterocyclic acids, afforded the corresponding benzoyl-substituted heteroarenes in moderate to good yields. This protocol offers an economical, mild, and sustainable strategy for the synthesis of valuable aromatic ketones, thereby advancing the field of dual photoredox/palladium catalysis.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135037"},"PeriodicalIF":2.2,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475098","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 : 2025-10-31DOI: 10.1016/j.tet.2025.135035
Joseph Pisano, Yixiao Li, José S. Madalengoitia
Tertiary allylic amines tethered to primary amines react with thiophosgene in the presence of NaHCO3 to afford cyclic S-allylic isothioureas through a proposed cationic 1-thia-3-aza-Claisen rearrangement. Yields for the 2-carbon tether substrates range from 48 % to 65 %, while yields for the 3-carbon tether substrates range from 56 % to 99 %. Substrate scope studies indicate tolerance for a range of non-migrating groups on the tertiary amine while a range of allylic groups are tolerated as the migrating group. Competition studies between a crotyl and allyl group on the tertiary allylic amine show chemoselective rearrangement of the crotyl group over the allyl group. DFT calculations are consistent with the proposed cationic 1-thia-3-aza-Claisen rearrangement and the chemo selective rearrangement of a crotyl group over an allyl group.
{"title":"Cationic 1-thia-3-aza-Claisen rearrangement entry to cyclic S-allylic isothioureas","authors":"Joseph Pisano, Yixiao Li, José S. Madalengoitia","doi":"10.1016/j.tet.2025.135035","DOIUrl":"10.1016/j.tet.2025.135035","url":null,"abstract":"<div><div>Tertiary allylic amines tethered to primary amines react with thiophosgene in the presence of NaHCO<sub>3</sub> to afford cyclic <em>S</em>-allylic isothioureas through a proposed cationic 1-thia-3-aza-Claisen rearrangement. Yields for the 2-carbon tether substrates range from 48 % to 65 %, while yields for the 3-carbon tether substrates range from 56 % to 99 %. Substrate scope studies indicate tolerance for a range of non-migrating groups on the tertiary amine while a range of allylic groups are tolerated as the migrating group. Competition studies between a crotyl and allyl group on the tertiary allylic amine show chemoselective rearrangement of the crotyl group over the allyl group. DFT calculations are consistent with the proposed cationic 1-thia-3-aza-Claisen rearrangement and the chemo selective rearrangement of a crotyl group over an allyl group.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135035"},"PeriodicalIF":2.2,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475106","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 : 2025-10-31DOI: 10.1016/j.tet.2025.135026
Ian Merski, Jinya Yin, Ryan T. Vanderlinden, Jon D. Rainier
Described in this manuscript are intramolecular [2 + 2] photocycloadditions of readily available 2° vinylogous imidonaphthoquinones. In contrast to the reactivity of 3° vinylogous imidonaphthoquinones, subjecting the corresponding 2° substrates to 419 nm light results in the formation of novel bridged tetracyclic aza-anthraquinones from rare crossed [2 + 2] cycloaddition reactions.
{"title":"Vinylogous imidonaphthoquinone [2+2] photocycloadditions to bridged aza-anthraquinones","authors":"Ian Merski, Jinya Yin, Ryan T. Vanderlinden, Jon D. Rainier","doi":"10.1016/j.tet.2025.135026","DOIUrl":"10.1016/j.tet.2025.135026","url":null,"abstract":"<div><div>Described in this manuscript are intramolecular [2 + 2] photocycloadditions of readily available 2° vinylogous imidonaphthoquinones. In contrast to the reactivity of 3° vinylogous imidonaphthoquinones, subjecting the corresponding 2° substrates to 419 nm light results in the formation of novel bridged tetracyclic aza-anthraquinones from rare crossed [2 + 2] cycloaddition reactions.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135026"},"PeriodicalIF":2.2,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475103","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 : 2025-10-30DOI: 10.1016/j.tet.2025.135029
Olajide B. Omoyeni , Temitope O. Olomola , Nusrat O. Omisore , Taiwo F. Ojo , Craig A. Obafemi
A series of eight spirocyclic oxindole derivatives 1a–1d, 2a–2d was synthesized according to established methods; this included the previously unreported compound, 2c. The structures of all compounds were unequivocally characterised by spectroscopic analysis (IR, 1H NMR, 13C NMR) and high-resolution mass spectrometry (HRMS). The in vitro antibacterial activity was assessed against representative Gram-positive (Bacillus subtilis, Bacillus anthracis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacterial strains by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The compounds exhibited a range of bactericidal effects. Notably, derivative 2c demonstrated potent, broad-spectrum activity against B. subtilis, B. anthracis, and E. coli. Furthermore, both 2b and 2c exhibited significant efficacy against a clinically resistant strain of P. aeruginosa. In contrast, compounds 1a and 1d showed negligible antibacterial activity. These results underscore the potential of the spirocyclic oxindole scaffold in the development of novel antibacterial agents. This study provides a foundation for future work to optimize the structure-activity relationship and elucidate the precise mechanism of action of these compounds.
{"title":"Exploring the antibacterial potential of spirocyclic oxindole derivatives: Synthesis and biological evaluation","authors":"Olajide B. Omoyeni , Temitope O. Olomola , Nusrat O. Omisore , Taiwo F. Ojo , Craig A. Obafemi","doi":"10.1016/j.tet.2025.135029","DOIUrl":"10.1016/j.tet.2025.135029","url":null,"abstract":"<div><div>A series of eight spirocyclic oxindole derivatives <strong>1a–1d</strong>, <strong>2a–2d</strong> was synthesized according to established methods; this included the previously unreported compound, <strong>2c</strong>. The structures of all compounds were unequivocally characterised by spectroscopic analysis (IR, <sup>1</sup>H NMR, <sup>13</sup>C NMR) and high-resolution mass spectrometry (HRMS). The in vitro antibacterial activity was assessed against representative Gram-positive (<em>Bacillus subtilis</em>, <em>Bacillus anthracis</em>) and Gram-negative (<em>Escherichia coli</em>, <em>Pseudomonas aeruginosa</em>) bacterial strains by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The compounds exhibited a range of bactericidal effects. Notably, derivative <strong>2c</strong> demonstrated potent, broad-spectrum activity against <em>B. subtilis</em>, <em>B. anthracis</em>, and <em>E. coli</em>. Furthermore, both <strong>2b</strong> and <strong>2c</strong> exhibited significant efficacy against a clinically resistant strain of <em>P. aeruginosa</em>. In contrast, compounds <strong>1a</strong> and <strong>1d</strong> showed negligible antibacterial activity. These results underscore the potential of the spirocyclic oxindole scaffold in the development of novel antibacterial agents. This study provides a foundation for future work to optimize the structure-activity relationship and elucidate the precise mechanism of action of these compounds.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"190 ","pages":"Article 135029"},"PeriodicalIF":2.2,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475105","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}
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