Chemistry of 1,3-dioxepins. XIII. (E)/(Z) configurational assignment of 4,7-dihydro-4-hydroxyimino-6-nitro-1,3-dioxepins

Jadrijević-Mladar Takač, Milena; Butula, Ivan; Vikić-Topić, Dražen; Dumić, Miljenko (1998) Chemistry of 1,3-dioxepins. XIII. (E)/(Z) configurational assignment of 4,7-dihydro-4-hydroxyimino-6-nitro-1,3-dioxepins. Croatica Chemica Acta, 71 (3). pp. 557-571. ISSN 0011-1643

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Abstract

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 two-dimensional homo- and hetero-nuclear H-1 and C-13 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.

Item Type:	Article
Uncontrolled Keywords:	1, 3-Dioxepins, 4, 7-dihydro-4-hydroxyimino-6-nitro-1, 3-dioxepins, (E)/(Z) configurational assignment, 1D and 2D NMR spectra, 1H and 13C NMR correlated spectra, differential NOE
Subjects:	NATURAL SCIENCES > Chemistry
Divisions:	NMR Center
Projects:	Project title Project leader Project code Project type Biotici i ksenobiotici Branka Zorc 006243 MZOS Izotopno obilježavanje i molekulske spektroskopije Goran Baranović 00980802 MZOS
Depositing User:	Dražen Vikić-Topić
Date Deposited:	26 Nov 2013 16:00
URI:	http://fulir.irb.hr/id/eprint/1143

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