Results 121 to 130 of about 1,413,381 (322)

Photocatalytic Cross‐Coupling of Phenols and Heteroaryl Halides With Machine Learning‐Guided Reaction Prediction

Angewandte Chemie, EarlyView.
Photocatalytic cross‐coupling: A redox‐neutral photochemical method enables direct C(sp2)─C(sp2) bond formation between phenols and heteroaryl halides using an organic dye and base. Complementary radical generation allows efficient cross‐coupling in up to 91% yield. Mechanistic studies, DFT, HTE, and machine learning rationalize and predict reactivity,
Matthew C. Carson, Alice Wu, Kalyana B. Duggal, Madeline E. Rotella, Marisa C. Kozlowski   +4 more
wiley   +2 more sources

Synthesis of chiral 2-methyl-5,6,7,8-tetrahydroquinolines from naturally occurring monoterpenes [PDF]

, 2004
The synthesis is reported of chiral substituted 2-methylpyridines, in which the pyridine rings are annulated at the 5,6-positions to the chiral frameworks originating from (-)-β-pinene, (-)-isopinocampheol and (+)-camphor.
Chelucci, Giorgio Adolfo, Orrù, Gianmauro, Soccolini, Francesco   +2 more
core  

NiH‐Catalyzed Enantioconvergent α‐Alkenylation of Carbonyl Compounds via Markovnikov Alkyne Hydronickellation

Angewandte Chemie, EarlyView.
A NiH‐catalyzed α‐alkenylation via Markovnikov hydronickellation of alkynes enables convenient access to α‐chrial β‐methylene carbonyl frameworks that are prevalent in biorelevant molecules. High regio‐ and enantioselectivities have been achieved with excellent functional group tolerance and applicability toward complex structures. The β‐methylene unit
Hyeontaek Nam, Seji Jang, Dongwook Kim, Sangwon Seo   +3 more
wiley   +2 more sources

Analysis and Evaluation of Volatile Chemical Components of Wild Ophiocordyceps sinensis and Its Mycelia in Xizang, China

Journal of Pharmacy and Bioallied Sciences
Background: As a rare traditional Chinese medicinal material, Ophiocordyceps sinensis is subject to counterfeiting in the market due to its limited distribution and insufficient supply and demand. Therefore, conducting research on its volatile components
Pei Qun, Zheng-Rong Lu, Jia-Yi Yang, Yan Liu, Zhan-Min Liu, Xuan-Wei Zhou   +5 more
doaj   +1 more source

Investigating the preparation of oxime derivatives of azacrown ethers containing piperidine-4-one heterocycles under microwave irradiation

Vietnam Journal of Science, Technology and Engineering
The use of multi-component reactions to simultaneously synthesise crown ethers and nitrogen-containing heterocycles is a synthetic approach that has attracted significant interest. With nitrogen heterocycles embedded in their structures, azacrown ethers
Tung H. To, Hieu D. Nguyen
doaj   +1 more source

Sequential Homo‐ and Hetero‐Coupling of Isocyanide and Carbon Monoxide Mediated by Acyclic Imino(silyl)Silylene

Angewandte Chemie, EarlyView.
We demonstrate the sequential reactions between an imino(hypersilyl)silylene and aryl isocyanide or carbon monoxide as a molecular‐level model of the Fischer–Tropsch process, providing systematic and detailed insight into C–C bond formation during the homologation of C1 building blocks.
Huaiyuan Zhu, Arseni Kostenko, Xufang Liu, Shigeyoshi Inoue   +3 more
wiley   +2 more sources

Radiation-driven Destruction of N-heterocycles in the Presence and Absence of Water Ice

The Astrophysical Journal
Simple N -heterocycles are expected to be an abundant class of molecules within the interstellar medium, and increasingly complex heterocycles (e.g., nucleobases) have been detected within meteoritic organic material and in samples returned from the ...
Patrick D. Tribbett, Yukiko Y. Yarnall, Perry A. Gerakines, Reggie L. Hudson, Christopher K. Materese   +4 more
doaj   +1 more source

Metal-free intermolecular formal cycloadditions enable an orthogonal access to nitrogen heterocycles

Nature Communications, 2016
Nitrogen containing heterocycles play key roles as both bioactive compounds and synthetic building blocks in organic chemistry. Here, the authors report the synthesis of a range of heterocyclic structures via metal free cycloadditions and provide ...
Lan-Gui Xie, Supaporn Niyomchon, Antonio J. Mota, Leticia González, Nuno Maulide   +4 more
doaj   +1 more source

Chemical characterization of liquefaction products of an inertinite enriched northern Alaska coals [PDF]

, 1989
A Northern Alaskan coal rich in inertinites was further enriched by density gradient separations. The degree of condensation of the enriched coal was estimated to be low, mainly 3 ring.
Mayasandra, Venugopal
core  

Formal pyridine meta-azidation and its application for the synthesis of diazepines, ring-fused δ-carbolines and 1,2,3-triazolylpyridines

Nature Communications
The nitrogen atom serves as an important structural element in pharmacologic studies, highlighting the critical role of nitrogen-containing heterocycles in drug discovery.
Shu-Min Guo, Pengwei Xu, Constantin G. Daniliuc, Armido Studer   +3 more
doaj   +1 more source