One unusual aromatic monacolin analog, aromonacolin A (1), was isolated from the ethanolic extract of Monascus purpureus-fermented rice. Its structure was elucidated by extensive spectroscopic (HRESIMS, (1)H NMR, (13)C NMR, HSQC, HMBC, and NOESY) and chemical methods. The absolute configuration of the C-6 secondary alcohol was deduced via the circular dichroism data of the in situ formed [Rh(2)(OCOCF(3))(4)] complex.
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http://dx.doi.org/10.1002/mrc.3851 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Inner Mongolia University, Chemistry and Chemical Engineering, 235 West University Street, 010021, Hohhot, CHINA.
Polycyclic aromatic hydrocarbons (PAHs) have attracted significant interest in material chemistry, particularly if they own extremely low band gaps and magnetic properties. However, challenges remain regarding the synthetic accessibility and energy saturation issues. In this study, we introduce NR-11, which consists of eleven aromatic rings in its main conjugation and is separately doped with two electron-rich nitrogen atoms.
View Article and Find Full Text PDFJACS Au
December 2024
State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China.
Nitroaromatics, as an important member and source of nitrogen-containing aromatics, is bringing enormous economic benefits in fields of pharmaceuticals, dyes, pesticides, functional materials, fertilizers, and explosives. Nonetheless, the notoriously polluting nitration industry, which suffers from excessive discharge of fumes and waste acids, poor functional group tolerance, and tremendous purification difficulty, renders mild, efficient, and environmentally friendly nitration a formidable challenge. Herein, we develop a visible-light-driven biocompatible arene C-H nitration strategy with good efficiency and regioselectivity, marvelous substrate applicability and functional group tolerance, and wide application in scale-up synthesis, total synthesis, and late-stage functionalization.
View Article and Find Full Text PDFCommun Chem
December 2024
Anorganische Chemie, Universität Göttingen, Göttingen, Germany.
The search for stable compounds containing an antiaromatic cyclic 4π system is a challenge for inventive chemists that can look back on a long history. Here we report the isolation and characterization of the novel 4π-electron tetrasilacyclobutadiene, an analogue of a 4π neutral cyclobutadiene that exhibits surprising features of a Möbius-type aromatic ring. Reduction of RSiCl (R = (Pr)PCH) with KC in the presence of cycloalkyl amino-carbene (cAAC) led to the formation of corresponding silylene 1.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
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 PDFChem Biodivers
December 2024
State Key Laboratory of Bioactive Molecules and Druggability Assessment, and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM & New Drugs Research College of Pharmacy, Jinan University, Guangzhou, P. R. China.
An unusual C nor-halimane-type diterpenoid, norcrohalane A (1), a new nor-lasserane-type sesquiterpenoid, norcrolasane A (2), along with four known compounds (3-6) were isolated from the roots of Croton crassifolius. Compound 1 represents the first example of a C nor-halimane-type diterpenoid, which features a rare 6/6/6 tricyclic ring system, and the A ring is aromatic. Compound 2 is a rare nor-lasserane-type sesquiterpenoid.
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