Preeti Ashokkumar Chaudhran, Sakshi Y. Mastoli, Abhishek Dey, Shubhini A. Saraf, Abha Sharma
A library of fluorescent molecules based on imidazopyridine linked with benzothiazole and benzimidazole was assessed for pH sensitivity and the effect of substituents thereon, also leading to dual-state emission. A broad range of pH (1–13) was evaluated, where the benzothiazole-based (BnTA) compounds responded in acidic pH, whereas the benzimidazole-based (BnIm) compounds behaved differently at different pH with recognizable color change on shifting from acidic to neutral and then to basic. NMR titrations revealed the effect of substituents on governing the site of protonation and deprotonation. Further, the mechanism of fluorescence was comprehended through theoretical calculations. On assessing the solid state fluorescence briefly, 2e showed mechanochromic behavior, showing green fluorescence in the solid state, which vanished upon grinding, and upon fuming with acetone, the fluorescence turned yellowish orange, which reverted to the initial fluorescence upon long-term exposure of acetone. The cellular uptake and fluorescence response of 2l in pH were also evaluated. The colocalization experiment suggested that 2l crossed the nuclear membrane and stained the nucleus, showing its possible in vitro application. The compound serves as a potential lead for other applications likewise, such as optoelectronics, data encryption, and pH sensors.
{"title":"Dual-State Emissive and Substituent-Tunable pH-Sensitive Bis-Heterocyclic Fluorescent Probes","authors":"Preeti Ashokkumar Chaudhran, Sakshi Y. Mastoli, Abhishek Dey, Shubhini A. Saraf, Abha Sharma","doi":"10.1021/acs.joc.4c02563","DOIUrl":"https://doi.org/10.1021/acs.joc.4c02563","url":null,"abstract":"A library of fluorescent molecules based on imidazopyridine linked with benzothiazole and benzimidazole was assessed for pH sensitivity and the effect of substituents thereon, also leading to dual-state emission. A broad range of pH (1–13) was evaluated, where the benzothiazole-based (BnTA) compounds responded in acidic pH, whereas the benzimidazole-based (BnIm) compounds behaved differently at different pH with recognizable color change on shifting from acidic to neutral and then to basic. NMR titrations revealed the effect of substituents on governing the site of protonation and deprotonation. Further, the mechanism of fluorescence was comprehended through theoretical calculations. On assessing the solid state fluorescence briefly, <b>2e</b> showed mechanochromic behavior, showing green fluorescence in the solid state, which vanished upon grinding, and upon fuming with acetone, the fluorescence turned yellowish orange, which reverted to the initial fluorescence upon long-term exposure of acetone. The cellular uptake and fluorescence response of <b>2l</b> in pH were also evaluated. The colocalization experiment suggested that <b>2l</b> crossed the nuclear membrane and stained the nucleus, showing its possible in vitro application. The compound serves as a potential lead for other applications likewise, such as optoelectronics, data encryption, and pH sensors.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"26 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A Lewis base-catalyzed [4 + 3] annulation between dinucleophilic indole-2-carboxamides and Morita–Baylis–Hillmann (MBH) carbonates was developed to access densely substituted indole-1,2-fused diazepanones. This reaction is initiated by a Lewis base-catalyzed N-allylic alkylation of the indole scaffold with MBH carbonates, followed by intramolecular Michael cyclization. Notably, the selectivity of this process is controlled by a removable o-methoxyphenyl (OMP) directing group attached to the indole-2-carboxamides. The wide scope of substrates, high regio- and stereoselectivity, and diverse transformations highlight the potential synthetic utility of this method in drug discovery.
{"title":"Directing Group-Controlled Regioselective [4 + 3] Annulation of Indole-2-Carboxamides with MBH Carbonates toward Highly Substituted Indole-1,2-Fused Diazepanones","authors":"Shutao Wang, Wenyao Zhang, Zhuoqi Zhang, Jinbao Xiang, Lianyou Zheng","doi":"10.1021/acs.joc.5c00335","DOIUrl":"https://doi.org/10.1021/acs.joc.5c00335","url":null,"abstract":"A Lewis base-catalyzed [4 + 3] annulation between dinucleophilic indole-2-carboxamides and Morita–Baylis–Hillmann (MBH) carbonates was developed to access densely substituted indole-1,2-fused diazepanones. This reaction is initiated by a Lewis base-catalyzed <i>N</i>-allylic alkylation of the indole scaffold with MBH carbonates, followed by intramolecular Michael cyclization. Notably, the selectivity of this process is controlled by a removable <i>o</i>-methoxyphenyl (OMP) directing group attached to the indole-2-carboxamides. The wide scope of substrates, high regio- and stereoselectivity, and diverse transformations highlight the potential synthetic utility of this method in drug discovery.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"99 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A palladium-catalyzed new mode of cascade arylative cyclization of 1,6-diynes is disclosed using dibenzoxaborin as an arylating agent featuring transmetalation and selective migratory insertion as the key steps. This process enables the efficient construction of polysubstituted fused naphthalene skeletons via the formation of three new C–C bonds through dual regioselectivity in both arylation as well as C–H functionalization. Some control experiments and kinetic isotope effect (KIE) studies were conducted to elucidate the reaction mechanism, and some product diversifications were achieved to showcase the synthetic potential.
{"title":"Pd-Catalyzed Selective Arylative Cascade Cyclization of 1,6-Diynes and Dibenzoxaborins for Fused Naphthalene Derivatives","authors":"Muniganti Naveen Kumar, Shivunapuram Mahesh, Jagadeesh Babu Nanubolu, Maddi Sridhar Reddy","doi":"10.1021/acs.joc.5c00034","DOIUrl":"https://doi.org/10.1021/acs.joc.5c00034","url":null,"abstract":"A palladium-catalyzed new mode of cascade arylative cyclization of 1,6-diynes is disclosed using dibenzoxaborin as an arylating agent featuring transmetalation and selective migratory insertion as the key steps. This process enables the efficient construction of polysubstituted fused naphthalene skeletons via the formation of three new C–C bonds through dual regioselectivity in both arylation as well as C–H functionalization. Some control experiments and kinetic isotope effect (KIE) studies were conducted to elucidate the reaction mechanism, and some product diversifications were achieved to showcase the synthetic potential.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"17 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An efficient and attractive method for the synthesis of valuable benzofuran-3(2H)-one derivatives bearing a quaternary center in one step by employing dimethyl sulfoxide (DMSO) as a dual synthon under metal-free conditions has been developed. In this reaction, DMSO activated by cyanuric chloride (TCT) provides two different units (CH3 and SMe) in the target molecules, and the construction of the quaternary carbon center in the benzofuran-3(2H)-ones can be controlled by the addition of water. Furthermore, the functional group compatibility and synthetic value were demonstrated by scope evaluation and gram-scale experiments. The mechanistic studies show that the reaction may proceed via a radical process.
{"title":"TCT-Mediated and Water-Controlled Synthesis of Benzofuran-3(2H)-ones Bearing a Quaternary Carbon Center via a Radical Process Using Dimethyl Sulfoxide as a Dual Synthon","authors":"Qing Chen, Zhao Du, Chuanqi Liu, Xiaoqian Wang, Wantong Yue, Yilei Wang, Zhihua Peng","doi":"10.1021/acs.joc.5c00201","DOIUrl":"https://doi.org/10.1021/acs.joc.5c00201","url":null,"abstract":"An efficient and attractive method for the synthesis of valuable benzofuran-3(2<i>H</i>)-one derivatives bearing a quaternary center in one step by employing dimethyl sulfoxide (DMSO) as a dual synthon under metal-free conditions has been developed. In this reaction, DMSO activated by cyanuric chloride (TCT) provides two different units (CH<sub>3</sub> and SMe) in the target molecules, and the construction of the quaternary carbon center in the benzofuran-3(2<i>H</i>)-ones can be controlled by the addition of water. Furthermore, the functional group compatibility and synthetic value were demonstrated by scope evaluation and gram-scale experiments. The mechanistic studies show that the reaction may proceed via a radical process.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"183 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kai-Cheng Liang, Tian-Peng Ling, Hai-Tao Qin, Feng Liu
The halogenophilic SN2X reaction involving a nucleophilic attack on the X group from the front is less sensitive to backside steric hindrance. Herein, we report a mild and efficient SN2X reaction for sulfinylation of activated tertiary alkyl halides, which could provide a novel method for accessing sulfoxides decorated with a congested carbon center. Preliminary mechanistic studies indicated that the generated sulfinyl bromides would be the key electrophilic intermediates in the reaction.
{"title":"Sulfinylation of Tertiary Alkyl Halides via a Halogenophilic Substitution (SN2X) Reaction","authors":"Kai-Cheng Liang, Tian-Peng Ling, Hai-Tao Qin, Feng Liu","doi":"10.1021/acs.joc.4c03021","DOIUrl":"https://doi.org/10.1021/acs.joc.4c03021","url":null,"abstract":"The halogenophilic S<sub>N</sub>2X reaction involving a nucleophilic attack on the X group from the front is less sensitive to backside steric hindrance. Herein, we report a mild and efficient S<sub>N</sub>2X reaction for sulfinylation of activated tertiary alkyl halides, which could provide a novel method for accessing sulfoxides decorated with a congested carbon center. Preliminary mechanistic studies indicated that the generated sulfinyl bromides would be the key electrophilic intermediates in the reaction.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"27 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An NIS-promoted cascade of intramolecular C–N bond formation/aromatization with 3-(1H-indol-3-yl)-2-(pyridin-2-yl)propanoates is described for synthesizing a polycyclic indole skeleton, indolo[3,2-c]quinolizine, as well as 1,9-dihydropyrazolo[4’,3′:5,6]pyrido[2,3-b]indole. The advantages of this protocol include accessible starting materials, mild conditions, simple operation, and good yields. Indolo[3,2-c]quinolizines exhibited good fluorescence properties and effective staining for live cells, targeting lysosomes and mitochondria. Additionally, the products showed significant antiproliferative activity against tumor cells in the MTT assay.
{"title":"N-Iodosuccinimide-Promoted Synthesis of Indolo[3,2-c]quinolizines via Cascade Intramolecular C–N Bond Formation/Aromatization with 3-(1H-Indol-3-yl)-2-(pyridin-2-yl)propanoates","authors":"Chen Chen, Xixiang Yang, Jiaxin Wang, Weiya Kong, Jianjun Chen, Xiaodong Tang","doi":"10.1021/acs.joc.4c03039","DOIUrl":"https://doi.org/10.1021/acs.joc.4c03039","url":null,"abstract":"An NIS-promoted cascade of intramolecular C–N bond formation/aromatization with 3-(1<i>H</i>-indol-3-yl)-2-(pyridin-2-yl)propanoates is described for synthesizing a polycyclic indole skeleton, indolo[3,2-<i>c</i>]quinolizine, as well as 1,9-dihydropyrazolo[4’,3′:5,6]pyrido[2,3-<i>b</i>]indole. The advantages of this protocol include accessible starting materials, mild conditions, simple operation, and good yields. Indolo[3,2-<i>c</i>]quinolizines exhibited good fluorescence properties and effective staining for live cells, targeting lysosomes and mitochondria. Additionally, the products showed significant antiproliferative activity against tumor cells in the MTT assay.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"74 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An efficient method for reductive deoxygenation of isatin derivatives using catalyst B(C6F5)3 and methylphenylsilane is described. This reaction proceeds rapidly under mild conditions, and the protocol provides a broad substrate scope. Notably, while general synthetic methods utilizing a combination of B(C6F5)3 and hydrosilanes smoothly reduce indoles to generate indolines, the present strategy represents the first reductive deoxygenation reaction for the formation of indoles without further reduction.
{"title":"B(C6F5)3-Catalyzed Reductive Deoxygenation of Isatins for Indole Synthesis","authors":"Seung Deok Son, Hoe Young Choi, Haye Min Ko","doi":"10.1021/acs.joc.5c00345","DOIUrl":"https://doi.org/10.1021/acs.joc.5c00345","url":null,"abstract":"An efficient method for reductive deoxygenation of isatin derivatives using catalyst B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> and methylphenylsilane is described. This reaction proceeds rapidly under mild conditions, and the protocol provides a broad substrate scope. Notably, while general synthetic methods utilizing a combination of B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> and hydrosilanes smoothly reduce indoles to generate indolines, the present strategy represents the first reductive deoxygenation reaction for the formation of indoles without further reduction.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"33 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A visible-light-promoted FeCl3-catalyzed protocol for the generation of alkyl and silyl radicals from alkanes and silanes, respectively, is described. Employing a chlorine radical as a hydrogen atom transfer agent, alkyl, and silyl radicals were accessed and functionalized by addition to coumarins, ultimately resulting in a redox-neutral alkylation/silylation. The reaction occurs without an exogenous oxidant and under mild conditions, highlighting the potential of 3D-metal compounds in achieving challenging bond activations via photochemical excitation.
{"title":"Visible-Light-Mediated, LMCT-Enabled C(sp3)-H Bond Alkylation of Alkanes and Silanes via C-4 Functionalization of Coumarins","authors":"Parashuram Sharma, Tavinder Singh, Nisha Rawat, Anand Singh","doi":"10.1021/acs.joc.5c00265","DOIUrl":"https://doi.org/10.1021/acs.joc.5c00265","url":null,"abstract":"A visible-light-promoted FeCl<sub>3</sub>-catalyzed protocol for the generation of alkyl and silyl radicals from alkanes and silanes, respectively, is described. Employing a chlorine radical as a hydrogen atom transfer agent, alkyl, and silyl radicals were accessed and functionalized by addition to coumarins, ultimately resulting in a redox-neutral alkylation/silylation. The reaction occurs without an exogenous oxidant and under mild conditions, highlighting the potential of 3D-metal compounds in achieving challenging bond activations via photochemical excitation.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"39 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An environmentally friendly and practical method for the synthesis of various vinyl sulfones was developed through the direct sulfonylation of alkenyl sulfonium salts with sulfinic acids. The reaction was effectively triggered by the combined actions of milling, sunlight, and photocatalysts under solvent-free conditions, offering advantages such as a short reaction time (5–10 min), room temperature, and a straightforward workup procedure. Preliminary mechanistic studies suggested that a sulfonyl radical may be involved in this mechanophotocatalytic transformation process.
{"title":"Manual Grinding and Sunlight Synergistically Promoted Sulfonylation of Alkenyl Sulfonium Salts with Sulfinic Acids","authors":"Li-Hua Yang, Lin Chen, Wen-Shi Yao, Han-Yue Peng, Xiang-Qin Xu, Sha Peng, Long-Yong Xie","doi":"10.1021/acs.joc.4c03097","DOIUrl":"https://doi.org/10.1021/acs.joc.4c03097","url":null,"abstract":"An environmentally friendly and practical method for the synthesis of various vinyl sulfones was developed through the direct sulfonylation of alkenyl sulfonium salts with sulfinic acids. The reaction was effectively triggered by the combined actions of milling, sunlight, and photocatalysts under solvent-free conditions, offering advantages such as a short reaction time (5–10 min), room temperature, and a straightforward workup procedure. Preliminary mechanistic studies suggested that a sulfonyl radical may be involved in this mechanophotocatalytic transformation process.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"22 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Da-Wei Shi, Ming Li, Rui-Jia Yang, Xin-Yu Zhao, Ting Zhang, Jiayi Huangfu, Ling Xu, Ke Wang, Yi-Xuan Ma, Bin Yang
We have developed an umpolung method utilizing the Tf2O/DMSO-based system for C(sp2)–P bond or C(sp3)–P bond formation. This method employs both P(O)–H and P(O)–OH compounds as phosphorus sources and demonstrates excellent compatibility with a wide range of Grignard reagents. Without the requirement of precious transition metals or additives, this one-pot protocol provides a practical and efficient synthetic pathway to a variety of aryl and alkyl phosphine oxides. The broad substrate scope and diverse synthetic applications highlight the practical utility of this method.
{"title":"Tf2O/DMSO-Promoted Umpolung Phosphorylation for C(sp2)–P or C(sp3)–P Bond Formation","authors":"Da-Wei Shi, Ming Li, Rui-Jia Yang, Xin-Yu Zhao, Ting Zhang, Jiayi Huangfu, Ling Xu, Ke Wang, Yi-Xuan Ma, Bin Yang","doi":"10.1021/acs.joc.5c00262","DOIUrl":"https://doi.org/10.1021/acs.joc.5c00262","url":null,"abstract":"We have developed an umpolung method utilizing the Tf<sub>2</sub>O/DMSO-based system for C(sp<sup>2</sup>)–P bond or C(sp<sup>3</sup>)–P bond formation. This method employs both P(O)–H and P(O)–OH compounds as phosphorus sources and demonstrates excellent compatibility with a wide range of Grignard reagents. Without the requirement of precious transition metals or additives, this one-pot protocol provides a practical and efficient synthetic pathway to a variety of aryl and alkyl phosphine oxides. The broad substrate scope and diverse synthetic applications highlight the practical utility of this method.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"195 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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