The synthesis of structurally diverse heterocycles for chemical space exploration was achieved via the cascade reactions of indigo with propargylic electrophiles. New pyrazinodiindolodione, naphthyridinedione, azepinodiindolone, oxazinoindolone and pyrrolodione products were prepared in one pot reactions by varying the leaving group (-Cl, -Br, -OMs, -OTs) or propargyl terminal functionality (-H, -Me, -Ph, -Ar). Mechanistic and density functional theory studies revealed that the unsaturated propargyl moiety can behave as an electrophile when aromatic terminal substitutions are made, and therefore competes with leaving group substitution for new outcomes. Selected products from the cascade reactions were investigated for their absorption and fluorescence properties, including transient absorption spectroscopy. This revealed polarity dependent excited state relaxation pathways, fluorescence, and triplet formation, thus highlighting these reactions as a means to access diverse functional materials rapidly.
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http://dx.doi.org/10.1002/chem.202003662 | DOI Listing |
Food Chem
December 2024
Laboratory of Functional Polymers, School of Materials Science and Engineering, Linyi University, Linyi 276005, China. Electronic address:
Organicphosphorus is a ubiquitous pesticide that has potential hazards to human health and environmental well-being. Therefore, the precise identification of residues of organophosphorus pesticides (OPs) emerges as an urgent necessity. A ratiometric fluorescent sensor for the detection of OPs by leveraging the catalytic activities of Ce and Ce on the two fluorescent substrates 4-Methylumbelliferyl phosphate (4-MUP) and o-phenylenediamine (OPD) correspondingly was designed.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States.
We present a six-step cascade that converts 1,3-distyrylbenzenes (-stilbenes) into nonsymmetric pyrenes in 40-60% yields. This sequence merges photochemical steps, ,-alkene isomerization, a 6π photochemical electrocyclization (Mallory photocyclization); the new bay region cyclization, with two radical iodine-mediated aromatization steps; and an optional aryl migration. This work illustrates how the inherent challenges of engineering excited state reactivity can be addressed by logical design.
View Article and Find Full Text PDFToxins (Basel)
December 2024
Department of Chemistry, University of Ghana, Legon-Accra P.O. Box LG56, Ghana.
Mycolactone is a complex macrolide toxin produced by , the causative agent of Buruli ulcer. The aim of this paper is to review the chemistry, biosynthetic, and synthetic pathways of mycolactone A/B to help develop an understanding of the mode of action of these polyketides as well as their therapeutic potential. The synthetic work has largely been driven by the desire to afford researchers enough (≥100 mg) of the pure toxins for systematic biological studies toward understanding their very high biological activities.
View Article and Find Full Text PDFBiosensors (Basel)
November 2024
Department of BioNano Technology, Gachon University, 1342 Seongnamdae-ro, Sujeong-gu, Seongnam 13120, Republic of Korea.
Choline is an important molecule in monitoring food safety and infant nutrition. Here, we report Ce nanogels synthesized by atom transfer radical polymerization (ATRP) employing Ce-coordinated acryloyl-lysine polymer brushes (Ce@SiO NGs) as highly efficient cascade nanozymes for colorimetric detection of choline. The synthesized Ce@SiO NGs demonstrated remarkable peroxidase-like activity with a porous exterior, which are essential to entrap choline oxidase (COx) to yield COx@Ce@SiO NGs and construct a cascade reaction system to detect choline.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., Moscow 119991, Russian Federation.
The selective reaction of cyclic aminoperoxides with FeCl proceeds through a sequence of O-O and C-C bond cleavages, followed by intramolecular cyclization, yielding functionalized tetrahydrofurans in 44-82% yields. Replacing the peroxyacetal group in the peroxide structure with a peroxyaminal fragment fundamentally alters the reaction pathway. Instead of producing linear functionalized ketones, this modification leads to the formation of hard-to-access substituted tetrahydrofurans.
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