Curcumin has been transformed to racemic curcuminoids via an azomethine ylide cycloaddition reaction using isatin/acenaphthoquinone and proline as the reagents. The products were characterized by extensive 1D/2D NMR analysis and single-crystal X-ray crystallographic studies. The enantiomers of one racemic product were separated by HPLC on a Chiralcel OD-H column and were indeed confirmed by the CD spectra of the separated enantiomers.
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http://dx.doi.org/10.1021/acs.orglett.5b02085 | DOI Listing |
Pharmaceuticals (Basel)
November 2024
Laboratory of Nanobiotechnologies, Saint-Petersburg National Research Academic University of the Russian Academy of Sciences, Saint Petersburg 194021, Russia.
: A series of spiro-fused heterocyclic compounds containing cyclopropa[a]pyrrolizidine-2,3'-oxindole and 3-spiro[3-azabicyclo[3.1.0]-hexane]oxindole frameworks were synthesized and studied for their in vitro antiproliferative activity against human erythroleukemia (K562), cervical carcinoma (HeLa), acute T cell leukemia (Jurkat), melanoma (Sk-mel-2) and breast cancer (MCF-7) as well as mouse colon carcinoma (CT26) cell lines.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
College of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China.
A synthetic strategy of a three-component spiro-pyrrolidine compound based on benzofuran via an [3+2] azomethine ylide cycloaddition reaction is reported herein. Under mild optimal conditions, this reaction can quickly produce potentially bioactive compounds with a wide range of substrates, high yield, and simple operation. The desired products were obtained with a yield of 74-99% and a diastereomeric ratio (dr) of >20:1.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
The chiral amine catalyzed diastereo- and enantioselective [3 + 2] cycloaddition between isatin-derived azomethine ylides and α,β-unsaturated aldehydes was successfully carried out to afford spiro[oxindole-3,2'-pyrrolidine]s. It was anticipated that the formation of azomethine ylides occurred the cycloreversion of dispirooxindole-imidazolidines, which are precursor imine homodimers, in aqueous solvents.
View Article and Find Full Text PDFMolecules
December 2024
Center for Green Chemistry, Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, MA 02125, USA.
Chemistry
December 2024
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan.
Reactions of cyclic thioureas (1,3,4,5-tetramethylimidazol-2-thione and 1,3-dimethylimidazolidin-2-thione) and ureas (1,3,4,5-tetramethylimidazol-2-one and 1,3-dimethylimidazolidin-2-one) with an isolable dialkylsilylene were examined. In these reactions, cyclic thioureas served as sulfur and NHC (N-heterocyclic carbene) sources, and the corresponding silanethione and NHC-derived products formed via silanethione-NHC complexes. Reactions of cyclic ureas with the silylene afforded a new NHC and an isolable azomethine ylide.
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