A tandem isomerization--Markovnikov oxidation of linear allylic imidic esters is developed using bis(benzonitrile)palladium chloride as the catalyst and O as the sole oxidant, regiospecifically giving β-amino aldehydes as the product. -Butyl nitrite works as a simple, and the only, redox cocatalyst. BuOH proves to be a crucial solvent for achieving excellent yield and specificity toward -Markovnikov aldehyde products.
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http://dx.doi.org/10.1021/acs.orglett.1c03619 | DOI Listing |
J Am Chem Soc
January 2025
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
Despite tremendous progress of dienamine catalysis along with its application in enantioselective synthesis over nearly two decades, certain limitations, especially with respect to the regioselectivity in the dienamine generation step, continue to persist. To overcome these shortcomings of classical dienamine catalysis, we now introduce the concept of alkoxy-directed dienamine catalysis and apply it to the enantioselective arene construction by desymmetrizing -enediones through [4 + 2]-cycloaddition. Catalyzed by a diphenylprolinol silyl ether, this reaction utilizes γ-alkoxy α,β-unsaturated aldehydes as the substrate and proceeds in a highly regioselective fashion through the intermediacy of δ-alkoxy dienamine.
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January 2025
Laboratory of Food Biotechnology and Foods for Special Dietary Uses, Federal State Budgetary Scientific Institution Federal Research Center of Nutrition, Biotechnology and Food Safety, 109240 Moscow, Russia.
The development of plant-based meat substitutes is imperative for reducing animal fat intake and promoting dietary diversification. However, the flavor profiles of these products frequently fall short of consumer expectations. This study sought to optimize the production process of meat flavorings for plant-based products using the Taguchi method.
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January 2025
College of Biochemical Engineering, Beijing Union University, Beijing 100023, China.
The aroma of yak milk powder is a crucial sensory indicator for evaluating its quality and flavor. Yak milk powders collected from different lactation periods exhibit distinct flavors, but no studies have thoroughly investigated the aroma characteristics and variation patterns of yak milk powders across these periods. This study identified and analyzed the volatile compounds in freeze-dried colostrum powder (YCSP), freeze-dried mature milk powder (YMMP), and freeze-dried ending milk powder (YEMP) using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and multivariate statistical analysis.
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December 2024
College of Food Science and Engineering, Guiyang University, Guiyang 550005, China.
The effects of frying times (1, 2, 3, and 4 min) and temperatures (140, 160, 180, and 200 °C) were investigated on the nutritional components, color, texture, and volatile compounds of three varieties (808, 0912, and LM) from Guizhou, China. Increased frying time and temperature significantly reduced the moisture, polysaccharide, and protein contents, while increasing hardness and chewiness, and decreasing elasticity and extrusion resilience, negatively impacting overall quality. Optimal umami and sweet amino acid retention were achieved by frying at 160 °C frying for 1-3 min or 140-180 °C for 2 min.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Institute for Information Technologies Kragujevac, Department of Science, University of Kragujevac, Jovana Cvijića bb, 34000 Kragujevac, Serbia.
In this study, the antioxidant and prooxidant potency of protocatechuic aldehyde (PCA) was evaluated using density functional theory (DFT). The potency of direct scavenging of hydroperoxyl (HOO) and lipid peroxyl radicals (modeled by vinyl peroxyl, HC=CHOO) involved in lipid peroxidation was estimated. The repair of oxidative damage in biomolecules (lipids, proteins and nucleic acids) and the prooxidant ability of PCA phenoxyl radicals were considered.
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