A nickel-catalyzed C(sp^(2))–H alkynylation of unprotected α-substituted benzylamines is achieved by utilizing a transient directing group. The combination of a TDG with a nickel catalyst significantly improves the ...A nickel-catalyzed C(sp^(2))–H alkynylation of unprotected α-substituted benzylamines is achieved by utilizing a transient directing group. The combination of a TDG with a nickel catalyst significantly improves the reaction step and atom economy. It has been investigated that the 2,4,6-trimethylpyridine ligand was critical to achieve the optimized reactivity. This protocol provides a straightforward route for synthesizing the alkynylated free benzylamines, featuring good substrate compatibility and monoselectivity.展开更多
Anaerobic ammonium oxidation coupled to iron(III)reduction(Feammox)process has recently been recognized as an important pathway for removing ammonium in various natural habitats.However,our understanding for Feammox i...Anaerobic ammonium oxidation coupled to iron(III)reduction(Feammox)process has recently been recognized as an important pathway for removing ammonium in various natural habitats.However,our understanding for Feammox in river–estuary continuum is limited.In this study,stable isotope tracers and high-throughput amplicon sequencing were employed to determine Feammox rates and identify associated microbial communities in sediments along the Yangtze river–estuary continuum.Feammox rates averaged 0.0058±0.0069 mg N/(kg·d)and accounted for approximately 22.3%of the ammonium removed from the sediments.Sediment Fe(III),ammonium(NH_(4)^(+)),total organic carbon(TOC),and pH were identified as important factors influencing Feammox rates.Additionally,Spirochaeta,Caldilineaceae_uncultured,and Ignavibacterium were found potentially associated with Feammox,which had not been documented as Feammox-associated microbial taxa previously.This study demonstrates that Feammox plays a vital role in ammonium removal within the Yangtze river–estuary continuum,providing greater insight into nitrogen removal and cycling in aquatic ecosystems.展开更多
Tumescenamide A (1), isolated from Streptomyces tumescens YM23-20, consists of a cyclic depsipeptideand a side-chain 2,4-dimethylheptanoate (Dmh). Herein, we report the first total synthesis of tumescenamide A (1) and...Tumescenamide A (1), isolated from Streptomyces tumescens YM23-20, consists of a cyclic depsipeptideand a side-chain 2,4-dimethylheptanoate (Dmh). Herein, we report the first total synthesis of tumescenamide A (1) and establish its stereochemistry. The configuration of Dmh is 2S,4S and, notably, the configuration of Val is revised as D. In addition, a mild and practical method for the β-elimination of derivatives ofserine and threonine by using nano-K_(2)CO_(3) as a base was established. A highly stereoselective synthesis ofthe Dmh substructure was also developed.展开更多
A nickel-catalyzed cascade C(sp^(2))–H alkynylation/hydroamination of unprotectedα-substituted benzylamines is achieved using a transient directing group(TDG).The combination of a TDG with a nickel catalyst signific...A nickel-catalyzed cascade C(sp^(2))–H alkynylation/hydroamination of unprotectedα-substituted benzylamines is achieved using a transient directing group(TDG).The combination of a TDG with a nickel catalyst significantly improves the overall step-and atom-economy.Studies have shown that the p-trifluoromethylbenzoic acid ligand is critical for achieving C(sp^(2))–H alkynylation and subsequent intramolecular hydroamination.This protocol provides a straightforward and efficient route for synthesizing substituted 1H-isoindoles,featuring good substrate compatibility.展开更多
基金supported financially by the Excellent Going Abroad Expert's Training Program in Hebei Province (No. 201940)the Hebei Natural Science Foundation of China (No. H2020208030)the S & T Program of Hebei (No. 22567607H) for financial support。
文摘A nickel-catalyzed C(sp^(2))–H alkynylation of unprotected α-substituted benzylamines is achieved by utilizing a transient directing group. The combination of a TDG with a nickel catalyst significantly improves the reaction step and atom economy. It has been investigated that the 2,4,6-trimethylpyridine ligand was critical to achieve the optimized reactivity. This protocol provides a straightforward route for synthesizing the alkynylated free benzylamines, featuring good substrate compatibility and monoselectivity.
基金supported by the National Natural Science Foundation of China(Nos.U2040201,32201334,92251304,and 42271126),the Project of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou,No.GML20220017),the Outstanding Postdoctoral Project in Jiangsu Province(No.2022ZB455),the Chinese Postdoctoral Science Foundation(No.2022M721661)and the Project of State Key Laboratory of Lake Science and Environment(No.2022SKL019).
文摘Anaerobic ammonium oxidation coupled to iron(III)reduction(Feammox)process has recently been recognized as an important pathway for removing ammonium in various natural habitats.However,our understanding for Feammox in river–estuary continuum is limited.In this study,stable isotope tracers and high-throughput amplicon sequencing were employed to determine Feammox rates and identify associated microbial communities in sediments along the Yangtze river–estuary continuum.Feammox rates averaged 0.0058±0.0069 mg N/(kg·d)and accounted for approximately 22.3%of the ammonium removed from the sediments.Sediment Fe(III),ammonium(NH_(4)^(+)),total organic carbon(TOC),and pH were identified as important factors influencing Feammox rates.Additionally,Spirochaeta,Caldilineaceae_uncultured,and Ignavibacterium were found potentially associated with Feammox,which had not been documented as Feammox-associated microbial taxa previously.This study demonstrates that Feammox plays a vital role in ammonium removal within the Yangtze river–estuary continuum,providing greater insight into nitrogen removal and cycling in aquatic ecosystems.
基金The authors are grateful for the financial assistance received from the Basic Research Program of China(No.2010CB512007 and 2012CB723501)the National Natural Science Foundation of China(No.30472074,30873139,21978076)Hebei Provincial Natural Science Foundation of China(No.H2020208030).
文摘Tumescenamide A (1), isolated from Streptomyces tumescens YM23-20, consists of a cyclic depsipeptideand a side-chain 2,4-dimethylheptanoate (Dmh). Herein, we report the first total synthesis of tumescenamide A (1) and establish its stereochemistry. The configuration of Dmh is 2S,4S and, notably, the configuration of Val is revised as D. In addition, a mild and practical method for the β-elimination of derivatives ofserine and threonine by using nano-K_(2)CO_(3) as a base was established. A highly stereoselective synthesis ofthe Dmh substructure was also developed.
基金supported by the Excellent Going Abroad Expert's Training Program in Hebei Province(No.201940)S.L.was supported by the S&T Program of Hebei(No.22567607H)+3 种基金D.J.C.was supported by a National Health and Medical Research Council(Australia)Leadership Fellowship(2009564)ARC Centre of Excellence for Innovations in Peptide and Protein Science(CE200100012)L.Y.C.was supported by the CIPPS Parental Leave Momentum Initiative Grant(CE200100012)Advance Queensland Women's AcademicFoundation(WAF-6884942288).
文摘A nickel-catalyzed cascade C(sp^(2))–H alkynylation/hydroamination of unprotectedα-substituted benzylamines is achieved using a transient directing group(TDG).The combination of a TDG with a nickel catalyst significantly improves the overall step-and atom-economy.Studies have shown that the p-trifluoromethylbenzoic acid ligand is critical for achieving C(sp^(2))–H alkynylation and subsequent intramolecular hydroamination.This protocol provides a straightforward and efficient route for synthesizing substituted 1H-isoindoles,featuring good substrate compatibility.
