Here we describe a novel catalyst-free 1,3-dipolar cycloaddition bioconjugation approach for chemical modification of proteins. The dehydroalanine (Dha)-containing protein reacts with nitrile oxides generated in situ through 1,3-dipolar cycloaddition in fully aqueous-buffered systems. This leads to the formation of a new isoxazoline ring at a pre-defined site (Dha) of the protein. Furthermore, the 1-pyrene isoxazoline-installed annexin V acts as a fluorescent probe, which successfully labels the outer cellular membranes of human cholangiocarcinoma (HuCCA-1) cells for detection of apoptosis.
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http://dx.doi.org/10.1002/cbic.202300268 | DOI Listing |
Molecules
December 2024
Department of Chemistry and Biochemistry, Augustana University, Sioux Falls, SD 57197, USA.
This study examined the chemoselectivity and diastereoselectivity of silyl nitronate alkenyn-nitroethers in Intramolecular Silyl Nitronate Cycloadditions (ISNCs) to produce isoxazole derivatives with interesting medicinal properties. These reactions resulted in the formation of either dihydrofuro[3,4-c]isoxazolines/isoxazolidines and/or alkynyl moieties attached to 2,5-dihydrofuryl carbonyls. This study also discerned the diastereoselectivities of the resulting cyclic adducts and compared them to previous findings.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China.
A novel and highly efficient Pd-catalyzed approach for the synthesis of bis-heterocycles featuring both isoxazoline and methyleneindole motifs is demonstrated. The in situ formation of vinyl Pd(II) species through an alkyne-tethered carbamoyl chloride cyclization is crucial, and the innovative Pd-catalyzed carboetherification of β,γ-unsaturated oximes with vinyl Pd(II) species has been developed. This method is not only operationally straightforward but also exhibits a broad substrate scope and excellent functional group tolerance.
View Article and Find Full Text PDFRSC Adv
December 2024
Faculty of Pharmaceutical Sciences, Setsunan University 45-1 Nagaotoge-cho Hirakata Osaka 573-0101 Japan
Electrophilic aromatic substitution at the C5 position of isoxazolines and construction of a new quaternary carbon center were achieved in this paper. This is the first report of carbon-carbon (C-C) bond formation onto isoxazoline without compromising the ring structure. Various aromatics including heteroaromatics gave the desired products in good yields, especially aromatics bearing electron-donating groups.
View Article and Find Full Text PDFMolecules
November 2024
MSO, Institut des Molécules et Matériaux du Mans (IMMM), UMR CNRS 6283, Le Mans Université, Avenue O. Messiaen, 72085 Le Mans, CEDEX 9, France.
Oximation of substituted ketofurfuryl alcohols in the presence of hydroxylamine hydrochloride and pyridine in ethanol as solvent led to a new class of spiro derivatives presenting a 7-methylene-1,6-dioxa-2-azaspiro [4.4] nona-2,8-diene skeleton along with, in some cases, the predictable oxime. The structures of such spiro compounds were determined by 2D NMR spectroscopy.
View Article and Find Full Text PDFChem Asian J
January 2025
Division of Organic Chemistry, CSIR-National Chemical Laboratory, Pune, 411 008, India.
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