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Report | Regular issue | Vol 19, No. 3, 1982, pp.551-558
Published online, 1st January, 1970
DOI: 10.3987/R-1982-03-0551
2,3-Dihydrobenzo-γ-pyrone Oximes. Part VII. A Simple Method of Differentiation of Isomeric Derivatives of Δ2-Isoxazoline and Flavanone Oximes. A Correction of Some Structures

Zbigniew Witczak

*Faculty of Pharmacy, School of Medicine, Department of Organic Chemistry, Institute of Chemical Sciences, 90-145 Lodz, Narutowicza 120a, Poland

Abstract

The simple method of differentiation of isomeric derivatives i.e. (E)-2,3-dihydro-2-(4-ethoxyphenyl)-4H-benzopyran-4-one oxime (2) and
corresponding Δ2-isoxazoline (3) on the basis of their UV and 1H NMR data, allows us to establish that the 2,3-dihydro-4H-benzopyran-4-one derivatives (4a-4d) in the reaction with hydroxylamine give oximes (5a-5d) instead of isomeric Δ2-isoxazolines as previously described12. The isomeric Δ2-isoxazoline derivatives (6b-6d) were obtained by trifluoroacetic acid-catalyzed rearrangement of obtained oximes (5b-5d).