The formation of intramolecular hydrogen bonds in anthraquinones makes them inert to photoinduced reactions; therefore, it is a great challenge to phototransform these compounds. Herein, we reported a formal visible-light-induced [4 + 2] cycloaddition of both 1-hydroxyanthraquinones and 1-aminoanthraquinones with olefins under external photocatalyst-free conditions with high regioselectivity. More than 60 substrates are disclosed, demonstrating the reliability of this protocol to construct diverse functionalized anthraquinone derivatives.
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http://dx.doi.org/10.1021/acs.orglett.3c03354 | DOI Listing |
Org Lett
January 2025
Department of Chemistry and Materials Science, College of Science, Nanjing Forestry University, Nanjing 210037, China.
The Nozaki-Hiyama-Kishi reaction offers effective and reliable strategies for the preparation of alcohols via carbon-carbon bond formation. Typical methods usually require stoichiometric amounts of chromium salts, co-transition metals, and auxiliary reagents, which limits their practical application in industrial chemistry. To mitigate these limitations, substantial efforts have been made to develop chromium-catalytic approaches.
View Article and Find Full Text PDFChemistry
January 2025
Indian Institute of Technology Madras, Department of Chemistry, Chennai, Chennai, INDIA.
A series of significantly bulky mono- and di-substituted cyclic alkyl-amino carbene (cAAC)- functionalized cyclopentadiene ring (Cp) compounds were synthesized. The functionalization of the Cp ring with cAAC ligands makes them significantly bulkier, while retaining their ligation properties. These compounds display interesting fluorescence properties.
View Article and Find Full Text PDFMol Phys
March 2024
Department of Physics, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States.
The stability of proteins and small peptides depends on the way they interact with the surrounding water molecules. For small peptides, such as -helical polyalanine (polyALA), water molecules can weaken the intramolecular hydrogen-bonds (HB) formed between the peptide backbone O and NH groups which are responsible for the -helix structure. Here, we perform molecular dynamics simulations to study the hydration of polyALA, polyserine (polySER), and other homopolymer peptide -helices at different temperatures and pressures.
View Article and Find Full Text PDFProteins
January 2025
Institute of Molecular Biosciences, University of Graz, Graz, Austria.
The Old Yellow Enzyme from Ferrovum sp. JA12 (FOYE) displays an unusual thermal stability for an enzyme isolated from a mesophilic organism. We determined the crystal structure of this enzyme and performed bioinformatic characterization to get insights into its thermal stability.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Pharmacy, Hangzhou Medical College, 8 Yikang Road, Hangzhou 311300, PR China.
A Fe-catalyzed hydrocyclization reaction of unactivated alkenes was developed, utilizing PhSiH as the hydrogen source, yielding 2,3-dihydroquinazolinone (DHQZ) derivatives in moderate to good yields. Notably, when the substrate was switched to -cyano--(2-(prop-1-en-2-yl)phenyl)benzamides, the reaction yielded only the unreduced products. Mechanistic studies revealed that the intramolecular addition of the in situ formed radical to the unactivated alkene results in the formation of the fused ring.
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