An uncharacterized terpene cyclase from Streptomyces pratensis was identified as (+)-(1(10)E,4E,6S,7R)-germacradien-6-ol synthase. The enzyme product exists as two interconvertible conformers, resulting in complex NMR spectra. For the complete assignment of NMR data, all fifteen ((13)C1)FPP isotopomers (FPP=farnesyl diphosphate) and ((13)C15)FPP were synthesized and enzymatically converted. The products were analyzed using various NMR techniques, including (13)C, (13)C COSY experiments. The ((13)C)FPP isotopomers were also used to investigate the thermal rearrangement and EI fragmentation of the enzyme product.
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http://dx.doi.org/10.1002/anie.201507615 | DOI Listing |
J Environ Manage
March 2025
National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization, Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Institute of Urban and Rural Mining, Changzhou University, Changzhou 213164, China. Electronic address:
Converting biomass waste into hydrogen energy through gasification is a crucial pathway for producing "green hydrogen". In a fixed bed reactor, a representative biomass waste, rice straw (RS), was pyrolyzed at N, HO, CO, and O atmospheres to generate hydrogen. Solid C-13 Nuclear Magnetic Resonance Spectroscopy (C-NMR) and Fourier Transform infrared spectroscopy (FTIR) were employed to elucidate the carbon structure and functional groups of the samples.
View Article and Find Full Text PDFJ Org Chem
March 2025
Department Chemie and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany.
4-Substituted 7-(4'-alkenyloxy)-1-indanones were prepared from the respective substituted aryl propanoic acids and subjected to UV-A irradiation (λ = 350 or 366 nm). While the 4-chloro compound was directly converted at λ = 366 nm into a pentacyclic product (47% yield) by a three-photon cascade process, the oxygenated substrates reacted in trifluoroethanol at λ = 350 nm by a two-photon cascade, involving an photocycloaddition, a thermal disrotatory ring opening, and a [4π] photocyclization (six examples, 67-82% yield). An ensuing photochemical di-π-methane rearrangement of the latter products was achieved by irradiation at λ = 350 nm in toluene (five examples, 36-70% yield).
View Article and Find Full Text PDFAcc Chem Res
March 2025
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210093, China.
ConspectusAmines are frequent structural components in natural products, pharmaceuticals, ligands, and catalysts, making their synthesis and transformation essential to organic chemistry. While C-N bond formation has become a well-established and reliable synthetic strategy, the selective cleavage of C-N bonds remains relatively underexplored. This challenge arises from the low heterolytic nucleofugality of nitrogen, a property that limits the practical application of C-N bond cleavage.
View Article and Find Full Text PDFChem Asian J
February 2025
Sao Paulo State University Julio de Mesquita Filho Institute of Chemistry: Universidade Estadual Paulista Julio de Mesquita Filho Instituto de Quimica, Departament Analytical, Physical-Chemistry and Inorganic, Francisco Degni Street, 14800-900, Araquarara, BRAZIL.
Magneto-optical borogermanate glasses were developed by incorporating electro-electronic waste recovered from fluorescent lamps. Glasses with a composition of (41GeO₂-25B₂O₃-4Al₂O₃-10Na₂O-20BaO)-x%wst, (x = 0, 10, 20, 30, and 50 wt% of waste) were prepared. The final chemical composition was determined, and the glasses were characterized through thermal, structural, morphological, optical, and magneto-optical analyses.
View Article and Find Full Text PDFInt J Biol Macromol
February 2025
MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Beijing 100083, China; Beijing Key Laboratory of Wood Science and Engineering, Beijing Forestry University, Beijing 100083, China. Electronic address:
A self-synthesized hyperbranched sulfuretted polyamidoamine-epichlorohydrin (PCDME) resin was developed to enhance high-temperature soybean meal (HSM) protein-based adhesives. In PCDME-modified HSM adhesives, a multi-crosslinked network is built based on ring-opening reactions, disulfide bond rearrangement, electrostatic interactions, and hydrogen bonding between the active groups in PCDME resins and HSM proteins. This results in the HSM-based adhesive with significantly enhanced internal cohesion, thermal stability, moisture resistance and bonding strength.
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