Variously substituted ethyl 6-oxo-1,6-dihydropyrimidine-5-carboxylates can be easily prepared by a metal carbonyl mediated rearrangement of ethyl 3-oxo-2-(1,2,4-oxadiazol-5-yl)propanoates. The irradiation of a mixture of oxadiazoles and Fe(CO) in wet solvents with a 365 nm LED at room temperature for 2 h followed by heating at 80 °C for 2 h gives pyrimidines in up to 90% yield. This procedure enables the preparation of 6-oxo-1,6-dihydropyrimidine-5-carboxylates with various aryl substituents at the C2 and alkyl or aryl substituents at the C4 position. 1-(1,2,4-Oxadiazol-5-yl)propan-2-ones analogously give 6-methylpyrimidin-4(3)-ones, albeit in lower yields. Ethyl 6-oxo-1,6-dihydropyrimidine-5-carboxylates can be easily modified at the C6 position by bromination followed by cross-coupling reactions to give pyrimidine-5-carboxylates with pyridyl, amino and ethynyl substituents.
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http://dx.doi.org/10.1039/d3ob00148b | DOI Listing |
Nanoscale
January 2025
State Key Laboratory of Biobased Fiber Manufacturing Technology, Tianjin Key Laboratory of Pulp and Paper, China Light Industry Key Laboratory of Papermaking and Biorefinery, Tianjin University of Science and Technology, No. 29, 13th Street, TEDA, Tianjin 300457, P. R. China.
The remarkable catalytic activity, optical properties, and electrochemical behavior of nanomaterials based on noble metals (NM) are profoundly influenced by their physical characteristics, including particle size, morphology, and crystal structure. Effective regulation of these parameters necessitates a refined methodology. Lignin, a natural aromatic compound abundant in hydroxyl, carbonyl, carboxyl, and sulfonic acid groups, has emerged as an eco-friendly surfactant, reducing agent, and dispersant, offering the potential to precisely control the particle size and morphology of NM-based nanomaterials.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India. Electronic address:
Biofilm formation is a key adaptive response of marine bacteria towards stress conditions. The protective mechanisms of biofilm matrixome proteins against heavy metals (Pb and Cd) induced oxidative damage in the marine bacterium Bacillus stercoris GST-03 was investigated. Exposure to heavy metals resulted in significant changes in cell morphology, biofilm formation, and matrixome composition.
View Article and Find Full Text PDFJ Contam Hydrol
December 2024
Division of Earth and Environmental System Sciences-Major of Environmental Geosciences, Pukyong National University, Busan 48513, South Korea; Wible Co Ltd, Pukyong National University, 365 Sinseon-ro, Nam-gu, Busan 48547, South Korea. Electronic address:
Microplastics (MPs) in aquatic environments adsorb heavy metals, thereby posing potential environmental risks. However, further research is needed to elucidate the adsorption behavior of different types of MPs for various heavy metals. The aim of this study was to characterize four types of MPs: polypropylene (PP), polyvinyl chloride (PVC), high-density polyethylene (HDPE), and low-density polyethylene (LDPE).
View Article and Find Full Text PDFMetallomics
December 2024
Department of Environmental and Physical Sciences, Faculty of Science.
Non-enzymatic glycation is the chemical reaction between the amine group of an amino acid and the carbonyl group of a reducing sugar. The final products of this reaction, advanced glycation end-products (AGEs), are known to play a key role in aging and many chronic diseases. The kinetics of the AGE formation reaction depends on several factors, including pH, temperature, and the presence of prooxidant metals, such as iron and copper.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Henan Key Laboratory of Crystalline Molecular Functional Materials, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
The conversion of methane and carbon dioxide to form C products is of great interest but presents a long-standing grand challenge due to the significant obstacle of activating the inert C-H and C═O bonds as well as forming the C-C bonds. Herein, the consecutive C-C coupling of CH and CO was realized by using heteronuclear metal cations CuTa, and the desorption of HC═C═O molecules was evidenced by state-of-the-art mass spectrometry. The CuTa reaction system is significantly different from the homonuclear metal systems of Cu and Ta.
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