Harry Kochat, J S Yadav, Vinod K Singh, S S V Ramasastry
{"title":"Professor (Dr) Sukh Dev: an iconic scientist with an innate sixth sense who radicalized natural product synthesis & organic chemistry.","authors":"Harry Kochat, J S Yadav, Vinod K Singh, S S V Ramasastry","doi":"10.1039/d4ob90071e","DOIUrl":"https://doi.org/10.1039/d4ob90071e","url":null,"abstract":"","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141449136","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}
Mukesh Kumar Nayak, Swati Chakraborty, Anuradha Mohanty, Sujit Roy
SnCl2 catalyzed the three-component coupling of aniline, epoxide, and paraformaldehyde, resulting in the synthesis of 1,3-oxazolidine derivatives. The reaction is simple and does not require any additives, bases, or oxidants, and proceeds at moderate temperature with good functional group tolerance. The scope of the utilization of paraformaldehyde as the methylene source was further extended to the synthesis of benzothiazole and 4,4'-methylenebis(N,N-dimethylaniline) using the same catalyst. A catalytic pathway was proposed based on the control experiments.
{"title":"SnCl<sub>2</sub>-catalyzed multicomponent coupling: synthesis of 1,3-oxazolidine derivatives using paraformaldehyde as a C1 feedstock.","authors":"Mukesh Kumar Nayak, Swati Chakraborty, Anuradha Mohanty, Sujit Roy","doi":"10.1039/d4ob00791c","DOIUrl":"https://doi.org/10.1039/d4ob00791c","url":null,"abstract":"<p><p>SnCl<sub>2</sub> catalyzed the three-component coupling of aniline, epoxide, and paraformaldehyde, resulting in the synthesis of 1,3-oxazolidine derivatives. The reaction is simple and does not require any additives, bases, or oxidants, and proceeds at moderate temperature with good functional group tolerance. The scope of the utilization of paraformaldehyde as the methylene source was further extended to the synthesis of benzothiazole and 4,4'-methylenebis(<i>N</i>,<i>N</i>-dimethylaniline) using the same catalyst. A catalytic pathway was proposed based on the control experiments.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141449138","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}
Sundaravel Vivek Kumar, Jeremiah Olusegun, Patrick J Guiry
The Zn(II)/UCD-Imphanol-catalyzed highly endo-selective [3 + 2] asymmetric cycloaddition of acyclic enones and azomethine ylides has been developed. Moderate to high yields (up to 94%) with excellent endo/exo selectivities (99 : 1) and enantioselectivities up to 96.5 : 3.5 er were obtained.
{"title":"Zn(II)-catalyzed asymmetric [3 + 2] cycloaddition of acyclic enones with azomethine ylides.","authors":"Sundaravel Vivek Kumar, Jeremiah Olusegun, Patrick J Guiry","doi":"10.1039/d4ob00854e","DOIUrl":"https://doi.org/10.1039/d4ob00854e","url":null,"abstract":"<p><p>The Zn(II)/UCD-Imphanol-catalyzed highly <i>endo</i>-selective [3 + 2] asymmetric cycloaddition of acyclic enones and azomethine ylides has been developed. Moderate to high yields (up to 94%) with excellent <i>endo</i>/<i>exo</i> selectivities (99 : 1) and enantioselectivities up to 96.5 : 3.5 er were obtained.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141449139","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}
Brønsted acid catalyzed regioselective ring opening of aziridines by phenols and thiophenols have been reported. Involvement of a series of aziridines with a range of phenols and thiophenols offer the generality of the reported protocol. Completion of the reaction at room temperature within very short time brings the uniqueness of the developed technique. To emphasis on the application of the developed methodology, the products have been used for the further synthesis of a range of useful and novel heterocyclic molecules such as indolines, indoles, benzothiazines, dihydrobenzothiazines, benzo-oxazines and benzochromenes.
{"title":"Regioselective Brønsted acid catalyzed ring opening of aziridines by phenols and thiophenols; a gateway to access functionalized indolines, indoles, benzothiazines, dihydrobenzo-thiazines, benzo-oxazines and benzochromenes.","authors":"Arnab Roy, Surajit Duari, Srabani Maity, Subrata Biswas, Abhishek Kumar Mishra, Srijit Biswas","doi":"10.1039/d4ob00196f","DOIUrl":"https://doi.org/10.1039/d4ob00196f","url":null,"abstract":"<p><p>Brønsted acid catalyzed regioselective ring opening of aziridines by phenols and thiophenols have been reported. Involvement of a series of aziridines with a range of phenols and thiophenols offer the generality of the reported protocol. Completion of the reaction at room temperature within very short time brings the uniqueness of the developed technique. To emphasis on the application of the developed methodology, the products have been used for the further synthesis of a range of useful and novel heterocyclic molecules such as indolines, indoles, benzothiazines, dihydrobenzothiazines, benzo-oxazines and benzochromenes.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141449137","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}
Peptide nucleic acid (PNA) is a prominent artificial nucleic acid mimetic and modifications at the γ-position of the peptidic backbone are known to further enhance the desirable properties of PNA in terms of duplex stability. Here, we leveraged a propargyl ether modification at this position for late stage functionalization of PNA to obtain positively charged (cationic amino and guanidinium groups), negatively charged (anionic carboxylate and alkyl phosphonate groups) and neutral (PEG) PNAs to assess the impact of these charges on DNA : PNA and PNA : PNA duplex formation. Thermal stability analysis findings concurred with prior studies showing PNA : DNA duplexes are moderately more stable with cationic PNAs than anionic PNAs at physiological salt concentrations. We show that this effect is derived predominantly from differences in the association kinetics. For PNA : PNA duplexes, anionic PNAs were found to form the most stable duplexes, more stable than neutral PNA : PNA duplexes.
{"title":"Impact of charges on the hybridization kinetics and thermal stability of PNA duplexes.","authors":"Miguel López-Tena, Nicolas Winssinger","doi":"10.1039/d4ob00887a","DOIUrl":"https://doi.org/10.1039/d4ob00887a","url":null,"abstract":"<p><p>Peptide nucleic acid (PNA) is a prominent artificial nucleic acid mimetic and modifications at the γ-position of the peptidic backbone are known to further enhance the desirable properties of PNA in terms of duplex stability. Here, we leveraged a propargyl ether modification at this position for late stage functionalization of PNA to obtain positively charged (cationic amino and guanidinium groups), negatively charged (anionic carboxylate and alkyl phosphonate groups) and neutral (PEG) PNAs to assess the impact of these charges on DNA : PNA and PNA : PNA duplex formation. Thermal stability analysis findings concurred with prior studies showing PNA : DNA duplexes are moderately more stable with cationic PNAs than anionic PNAs at physiological salt concentrations. We show that this effect is derived predominantly from differences in the association kinetics. For PNA : PNA duplexes, anionic PNAs were found to form the most stable duplexes, more stable than neutral PNA : PNA duplexes.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141449134","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}
We report herein an eosin Y/Pd(II) dual catalytic approach for regio- and chemoselective C(sp2)-H monoarylation of N-H unprotected 2-phenyl quinazolinone derivatives under green light irradiation with no necessity for any base/additive/external oxidant. The free N-H moiety was post-modified for quinazolinone scaffold diversification and C-H annulation.
{"title":"Green light-mediated dual eosin Y/Pd<sup>II</sup>-catalyzed C(sp<sup>2</sup>)-H arylation of N-H unprotected 2-arylquinazolinones.","authors":"Shuvam Mondal, Ranjan Jana","doi":"10.1039/d4ob00779d","DOIUrl":"https://doi.org/10.1039/d4ob00779d","url":null,"abstract":"<p><p>We report herein an eosin Y/Pd(II) dual catalytic approach for regio- and chemoselective C(sp<sup>2</sup>)-H monoarylation of N-H unprotected 2-phenyl quinazolinone derivatives under green light irradiation with no necessity for any base/additive/external oxidant. The free N-H moiety was post-modified for quinazolinone scaffold diversification and C-H annulation.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445625","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}
An organo-photoredox catalyzed gem-difluoroallylation of both acyclic and cyclic ketone derivatives with α-trifluoromethyl alkenes has been demonstrated, thus giving access to a diverse set of gem-difluoroalkenes in moderate to high yields. Pro-aromatic dihydroquinazolinones can be either pre-formed or in situ generated for ketone activation. This reaction is characterized by readily available starting materials, mild reaction conditions, and broad substrate scope. The feasibility of this reaction has been highlighted by the late-stage modification of several natural products and drug-like molecules as well as the in vitro antifungal activity.
{"title":"Organo-photoredox catalyzed <i>gem</i>-difluoroallylation of ketone-derived dihydroquinazolinones <i>via</i> C(sp<sup>3</sup>)-C bond and C(sp<sup>3</sup>)-F bond cleavage.","authors":"Yue Zhang, Tianshuai Zhu, Yuqian Lin, Xian Wei, Xinyu Xie, Ruofan Lin, Zhijie Zhang, Weiwei Fang, Jing-Jing Zhang, Yue Zhang, Meng-Yang Hu, Lingchao Cai, Zhen Chen","doi":"10.1039/d4ob00671b","DOIUrl":"https://doi.org/10.1039/d4ob00671b","url":null,"abstract":"<p><p>An organo-photoredox catalyzed <i>gem</i>-difluoroallylation of both acyclic and cyclic ketone derivatives with α-trifluoromethyl alkenes has been demonstrated, thus giving access to a diverse set of <i>gem</i>-difluoroalkenes in moderate to high yields. Pro-aromatic dihydroquinazolinones can be either pre-formed or <i>in situ</i> generated for ketone activation. This reaction is characterized by readily available starting materials, mild reaction conditions, and broad substrate scope. The feasibility of this reaction has been highlighted by the late-stage modification of several natural products and drug-like molecules as well as the <i>in vitro</i> antifungal activity.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445627","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}
Chenghui Dai, Yan Chen, Jiaqi Xu, Xueli Zheng, Hua Chen, Haiyan Fu, Ruixiang Li
Herein, the synthesis of branched α,β-unsaturated amides by a hydroaminocarbonylation reaction of alkynes with various amine substrates such as aromatic amines, aliphatic amines, solid amine sources like NH4HCO3, and even strongly basic piperidines is reported, using a Pd(OAc)2/hybrid N-heterocyclic carbene-phosphine-phosphine (CPP) catalytic system. The reactions feature no additives, wide substrate scope, high selectivity (b/l > 99 : 1) and excellent yields. Mechanistic studies have disclosed that the reaction takes place via a palladium hydride pathway. CPP adopts a hybrid bidentate ligand conformation with a carbene-phosphine coordination mode, wherein one phosphorus atom remains externally accessible, potentially serving as a stabilizing auxiliary during catalytic cycles.
{"title":"Highly selective and additive-free Pd(OAc)<sub>2</sub>/CPP catalyzed hydroaminocarbonylation of alkynes.","authors":"Chenghui Dai, Yan Chen, Jiaqi Xu, Xueli Zheng, Hua Chen, Haiyan Fu, Ruixiang Li","doi":"10.1039/d4ob00644e","DOIUrl":"https://doi.org/10.1039/d4ob00644e","url":null,"abstract":"<p><p>Herein, the synthesis of branched α,β-unsaturated amides by a hydroaminocarbonylation reaction of alkynes with various amine substrates such as aromatic amines, aliphatic amines, solid amine sources like NH<sub>4</sub>HCO<sub>3</sub>, and even strongly basic piperidines is reported, using a Pd(OAc)<sub>2</sub>/hybrid N-heterocyclic carbene-phosphine-phosphine (CPP) catalytic system. The reactions feature no additives, wide substrate scope, high selectivity (b/l > 99 : 1) and excellent yields. Mechanistic studies have disclosed that the reaction takes place <i>via</i> a palladium hydride pathway. CPP adopts a hybrid bidentate ligand conformation with a carbene-phosphine coordination mode, wherein one phosphorus atom remains externally accessible, potentially serving as a stabilizing auxiliary during catalytic cycles.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445626","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}
Mahesh K Lakshman, Casina T Malinchak, Nathaniel Shank, Michelle C Neary, Lothar Stahl
The purinyl ring contains four embedded nitrogen atoms of varying basicities. Selective utilization of these ring nitrogen atoms can lead to relatively facile remote functionalization, yielding modified purinyl motifs that are otherwise not easily obtained. Herein, we report previously undescribed N-directed aroylation of 6-arylpurine ribo and the more labile 2'-deoxyribonucleosides. Kinetic isotope analysis as well as reaction with a well-defined dimeric, palladated 9-benzyl 6-arylpurine provided evidence for N-directed cyclometallation as a key step, with a plausible rate-limiting C-H bond cleavage. Radical inhibition experiments indicate the likely intermediacy of aroyl radicals. The chemistry surmounts difficulties often posed in the functionalization of polynitrogenated and polyoxygenated nucleosidic structures that possess complex reactivities and a labile glycosidic bond that is more sensitive in the 2'-deoxy substrates.
{"title":"Purinyl <i>N</i>-directed aroylation of 6-arylpurine ribo- and 2'-deoxyribonucleosides, and mechanistic insights.","authors":"Mahesh K Lakshman, Casina T Malinchak, Nathaniel Shank, Michelle C Neary, Lothar Stahl","doi":"10.1039/d4ob00689e","DOIUrl":"https://doi.org/10.1039/d4ob00689e","url":null,"abstract":"<p><p>The purinyl ring contains four embedded nitrogen atoms of varying basicities. Selective utilization of these ring nitrogen atoms can lead to relatively facile remote functionalization, yielding modified purinyl motifs that are otherwise not easily obtained. Herein, we report previously undescribed <i>N</i>-directed aroylation of 6-arylpurine ribo and the more labile 2'-deoxyribonucleosides. Kinetic isotope analysis as well as reaction with a well-defined dimeric, palladated 9-benzyl 6-arylpurine provided evidence for <i>N</i>-directed cyclometallation as a key step, with a plausible rate-limiting C-H bond cleavage. Radical inhibition experiments indicate the likely intermediacy of aroyl radicals. The chemistry surmounts difficulties often posed in the functionalization of polynitrogenated and polyoxygenated nucleosidic structures that possess complex reactivities and a labile glycosidic bond that is more sensitive in the 2'-deoxy substrates.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445628","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}
N-Alkenyl 2-pyridonyl amines are afforded in high yields via a gold-catalyzed rearrangement of 2-propargyloxypyridine and 2-(but-3-yn-1-yloxy)pyridine under acidic conditions. This approach exhibits significant utility due to its outstanding efficiency of conversion in the synthesis of secondary amines as a one-pot reaction. The initial step of the method involves a cyclization reaction for the production of pyridinium salts, followed by the next stage, where rearrangement is accomplished through the nucleophilic addition phenomenon. This approach provides the conversion of primary amines into secondary amines, resulting in a single product. Furthermore, the methodology presents a high degree of tolerance towards several pyridine and aniline derivatives, resulting in the formation of products with excellent yields.
{"title":"Gold(I)-catalyzed synthesis of <i>N</i>-alkenyl 2-pyridonyl <i>sec</i>-amines.","authors":"Ali Osman Karatavuk","doi":"10.1039/d4ob00815d","DOIUrl":"https://doi.org/10.1039/d4ob00815d","url":null,"abstract":"<p><p><i>N</i>-Alkenyl 2-pyridonyl amines are afforded in high yields <i>via</i> a gold-catalyzed rearrangement of 2-propargyloxypyridine and 2-(but-3-yn-1-yloxy)pyridine under acidic conditions. This approach exhibits significant utility due to its outstanding efficiency of conversion in the synthesis of secondary amines as a one-pot reaction. The initial step of the method involves a cyclization reaction for the production of pyridinium salts, followed by the next stage, where rearrangement is accomplished through the nucleophilic addition phenomenon. This approach provides the conversion of primary amines into secondary amines, resulting in a single product. Furthermore, the methodology presents a high degree of tolerance towards several pyridine and aniline derivatives, resulting in the formation of products with excellent yields.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445624","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}