The reactivity of a range of pyridone and pyrazinone derivatives towards alkynes in the presence of cyclopentadienylcobaltbis(ethene) has been investigated. Depending on the nature of the substrates, [2+2+2]- or [2+2] cycloaddition, C-H, or N-H activation may occur. In the case of pyridones, the first three predominated with N-protected derivatives, whereas substrates containing N-H bonds followed an N-H activation pathway. The [2+2+2] cycloaddition of an N-butynylisoquinolone was applied successfully to the total synthesis of anhydrolycorinone. Pyrazinone substrates showed similar patterns of reactivity.
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http://dx.doi.org/10.1002/chem.200601823 | DOI Listing |
Ann Intern Med
January 2025
Center for Healthcare Delivery Sciences, Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts (R.J.D., N.K.C., N.H., J.C.L.).
Background: The evidence informing the harms of gabapentin use are at risk of bias from comparing users with nonusers.
Objective: To describe the risk for fall-related outcomes in older adults starting treatment with gabapentin versus duloxetine.
Design: New user, active comparator study using a target trial emulation framework.
J Am Chem Soc
January 2025
Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Front Chem
December 2024
Department of Chemistry and Biochemistry, Auburn University, Auburn, AL, United States.
High-level quantum chemical calculations are performed for the (NH)MO and (NH)MO species (M = Ti-Cu), extending our previous work on the bare MO ions. The potential energy curves along the M-O distance are constructed for the ground and multiple excited electronic states of (NH)MO and are compared to those of MO. We see that ammonia stabilizes the oxo states (MO) over the oxyl (MO) ones.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
December 2024
Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
In the present investigation, 13% ± 0.84 of the extracted and purified phycocyanin from Phormidium versicolor was obtained, with a purity of 0.69 following dialysis.
View Article and Find Full Text PDFDalton Trans
December 2024
Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
We report the proton-coupled electron transfer (PCET) reactivity of an octahedral Ta(V) aniline complex supported by an acridane-derived redox active NNN pincer ligand. The reversible binding of aniline to a Ta(V) dichloride induces significant coordination-induced bond weakening (CIBW) of the aniline N-H bonds. This enables a rare two-fold hydrogen atom abstraction, resulting in a terminal imido complex and a two-electron oxidation of the NNN pincer ligand, all while maintaining the metal's oxidation state.
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