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Chemistry of 1,3-Dioxepins. XIII. (E)/(Z) Configurational Assignment of 4,7-Dihydro-4-hydroxyimino-6-nitro-1,3-dioxepins

Milena Jadrijević-Mladar Takač ; Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biochemistry University of Zagreb, A. Kovačića 1, HR–10000 Zagreb, Croatia
Ivan Butula ; Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Biochemistry University of Zagreb, A. Kovačića 1, HR–10000 Zagreb, Croatia
Dražen Vikić-Topić ; Ruđer Bošković Institute, NMR Center, Bijenička cesta 54, HR–10001 Zagreb, Croatia
Miljenko Dumić ; PLIVA–Research Institute, Prilaz baruna Filipovića 25, HR–10000 Zagreb, Croatia

Sažetak

The configuration of oximes 1a and 1b was investigated by chemical and spectroscopic methods. Under the Beckmann rearrangement conditions, using sulfonyl chlorides as reagents, the sulfonic esters 2a-c were obtained. Under more drastic conditions, using PCl₅ or P₂O₅, the only isolated product was 4-nitro-5H-furan-2-on (3). It was also formed as the sole product by hydrolysis of oximes 1a-b, as well as sulfonic ester 2a. The structure of all compounds was determined by one- and twodimensional homo- and hetero-nuclear 1H and 13C NMR correlated spectra: COSY, NOESY, HETCOR and HMBC. Gradient selected differential NOE measurements confirmed that, in dimethylsulfoxide solution, oximes 1a and 1b exist in E-configuration, irrespective of the route of their formation.

Ključne riječi

Hrčak ID:

132367

URI

https://hrcak.srce.hr/132367

Datum izdavanja:

1.10.1998.

Posjeta: 938 *