Agroathelia rolfsii (A. rolfsii) is a fungal infection and poses a significant threat to over 500 plant species worldwide. It can reduce crop yields drastically resulting in substantial economic losses.
View Article and Find Full Text PDFThe quinazolinone scaffold is found in natural products and biologically active compounds, including inflammatory inhibitors. Major proteins or enzymes involved in the inflammation process are regulated by the amount of gene expression. Quinazolinone derivatives were investigated and developed against the inflammatory genes cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS) in the lipopolysaccharide (LPS)-stimulated RAW 264.
View Article and Find Full Text PDFA facile and green one-pot synthesis of AChE quinazolinone inhibitors was developed using microwave irradiation under solvent free conditions. Quinazolinones were synthesized from 2-aminobenzamide derivatives and various alcohols such as benzyl alcohol derivatives and butanol using economical commercially available copper as a catalyst in the presence of base, CsCO. The desired products were achieved in moderate to high yields with up to 92% isolated yield.
View Article and Find Full Text PDFNovel bidentate N-heterocyclic carbene-phosphine iridium complexes have been synthesized and evaluated in the hydrogenation of ketones. Reported catalytic systems require base additives and, if excluded, need elevated temperature or high pressure of hydrogen gas to achieve satisfactory reactivity. The developed catalysts showed extremely high reactivity and good enantioselectivity under base-free and mild conditions.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
July 2019
The development of new general methods for the synthesis of chiral fluorine-containing molecules is important for several scientific disciplines. We herein disclose a straightforward method for the preparation of chiral organofluorine molecules that is based on the iridium-catalyzed asymmetric hydrogenation of trisubstituted alkenyl fluorides. This catalytic asymmetric process enables the synthesis of chiral fluorine molecules with or without carbonyl substitution.
View Article and Find Full Text PDFThe synthesis of chiral fluorine containing motifs, in particular, chiral fluorine molecules with two contiguous stereogenic centers, has attracted much interest in research due to the limited number of methods available for their preparation. Herein, we report an atom-economical and highly stereoselective synthesis of chiral fluorine molecules with two contiguous stereogenic centers via azabicyclo iridium-oxazoline-phosphine-catalyzed hydrogenation of readily available vinyl fluorides. Various aromatic, aliphatic, and heterocyclic systems with a variety of functional groups were found to be compatible with the reaction and provide the highly desirable product as single diastereomers with excellent enantioselectivities.
View Article and Find Full Text PDFA number of cyclic olefins were prepared and evaluated for the asymmetric hydrogenation reaction using novel N,P-ligated iridium imidazole-based catalysts (Crabtree type). The diversity of these cyclic olefins spanned those having little functionality to others bearing strongly coordinating substituents and heterocycles. Excellent enantioselectivities were observed both for substrates having little functionality (up to >99% ee) and for substrates possessing functional groups several carbons away from the olefin.
View Article and Find Full Text PDFN-Heterocyclic carbene-phosphine iridium complexes (NHC-Ir) were developed/found to be a highly reactive catalyst for N-monoalkylation of amides with alcohols via hydrogen transfer. The reaction produced the desired product in high isolated yields using a wide range of substrates with low catalyst loading and short reaction times.
View Article and Find Full Text PDFAn N-heterocyclic carbene-phosphine iridium complex system was found to be a very efficient catalyst for the methylation of ketone via a hydrogen transfer reaction. Mild conditions together with low catalyst loading (1 mol %) were used for a tandem process which involves the dehydrogenation of methanol, C=C bond formation with a ketone, and hydrogenation of the new generated double bond by iridium hydride to give the alkylated product. Using this iridium catalyst system, a number of branched ketones were synthesized with good to excellent conversions and yields.
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