A diastereoselective one-pot synthesis of highly substituted dihydropyrimido[2,1-a]isoindole-6(2H)-ones containing three continuous stereocenters is reported. The reaction sequence is based on a hetero-Diels-Alder reaction between an enimide and a N-acylimine followed by an unprecedented Brønsted acid mediated rearrangement of an intermediate 5,6-dihydro-4H-1,3-oxazine to a pyrimido[2,1-a]isoindole.
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http://dx.doi.org/10.1021/acs.orglett.7b03545 | DOI Listing |
Chem Sci
January 2025
Instituto de Carboquímica (ICB-CSIC) C/Miguel Luesma Castán 4 E-50018 Zaragoza Spain
Fluorescent nitrogen-doped carbon dots (N-GQDs) with long-wavelength emission properties are of increased interest for technological applications. They are widely synthesized through the solvothermal treatment of graphene oxide (GO) using ,-dimethylformamide (DMF) as a cleaving and doping agent. However, this process simultaneously generates undesired interfering blue-emissive by-products.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemistry, National Institute of Technology Manipur, Imphal 795004, India.
A cost-effective, eco-friendly, and highly efficient one-pot electrochemical process has been described for the synthesis of 4-1,3-benzoxazine and 4,5-dihydro-1,3-benzoxazepine derivatives by employing 2-aminobenzyl alcohols, 2-(2-aminophenyl)ethan-1-ol, isothiocyanate derivatives, and TBAPF as an electrolyte. The developed method is accomplished at 25 °C with a constant current of 20 mA. Utilizing a graphite anode and a platinum cathode in a dimethyl sulfoxide solvent, the devised metal-free electrochemical approach minimizes the production of waste and eliminates the need for external oxidizing agents.
View Article and Find Full Text PDFNature
January 2025
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
Crosslinked thermosets are highly durable materials, but overcoming their petrochemical origins and inability to be recycled poses a grand challenge. Many strategies to access crosslinked polymers that are bioderived or degradable-by-design have been proposed, but they require several resource-intensive synthesis and purification steps and are not yet feasible alternatives to conventional consumer materials. Here we present a modular, one-pot synthesis of degradable thermosets from the commercially available, biosourced monomer 2,3-dihydrofuran (DHF).
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Organic Chemistry, Faculty of Chemistry, Alzahra University Vanak Tehran 1993893973 Iran
In this work, we present an efficient strategy for the straightforward synthesis of functionalized 1,6-dihydropyridine derivatives a three-component reaction of 3-vinylchromones, aromatic aldehydes, and ammonium acetate. A tandem procedure including NH aldimine formation/Michael-type addition/opening of the pyrone ring/isomerization/6π-electrocyclization/[1,5]-H shift allows rapid access to a series of dihydropyridines bearing an -hydroxybenzoyl and a benzoyl scaffold in good yields. Readily available precursors, simple heating conditions, and operational simplicity are some highlighted advantages of this transformation.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
Polyurethanes (PU) make up a large portion of commodity plastics appearing in applications including insulation, footwear, and memory foam mattresses. Unfortunately, as thermoset polymers, polyurethanes lack a clear path for recycling and repurposing, creating a sustainability issue. Herein, using dynamic depolymerization, we demonstrate a simple one-pot synthesis for preparation of an upcycled polyurethane grafted graphene material (PU-GO).
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