Bazı yeni benzensulfonil substitue izoksazolidin bileşiklerinin sentezi ve kütle spekrumlarının incelenmesi

ABSTRACT SYNTHESIS AND MASS SPECTROMETRY OF SOME NEW BENZENESULFONYL SUBSTITUTED ISOXAZOLIDINES ALTU?, Cevher M.Sc., Department of Chemistry Supervisor : Prof. Dr. Yaşar DÜRÜST December 2004, 119 pages In this work, the 1,3-dipolar cycloaddition (1,3 DC) reactions of some nitrones including a new one to the dipolarophile phenylvinyl sulfone are described. To our best knowledge of literature survey, nine new isoxazolidine compounds have been synthesized. Purification of the title compounds have been performed by means of flash column chromatography on silica gel.Also much attention was focused on the fragmentation ways of the cycloadducts, namely benzenesulfonyl substituted isoxazolidines, in electron impact mass spectrometry and the routes leading to described fragmentations were interpreted in terms of stability and substituents existing on the isoxazolidine ring. The structures of benzenesulfonyl substituted isoxazolidines were elucidated by means of İR, NMR (1H, 13C), MASS spectra and physical 111characteristics (melting points and Rf values). The stereochemistry of the isoxazolidine ring was determined by n.O.e experiments and was found to be trans configuration according to the groups on C-3 and C-4 carbons. Regiochemistry is also determined as to have been formed only 4- regioisomers but not 5-regioisomers based on the J coupling constants in 1H- NMR and n.O.e data. Keywords: 1,3-Dipolar cycloaddition, nitrones, isoxazolidine. IV