engleski

The Determination of Beckmann Rearrangement Products of 4, 7-Dihydro-5-nitro-4-oximino-1, 3- dioxepins by Spectroscopic Methods

Under the Beckmann rearrangement condition (alkyl- or arylsulfonylchlorides/pyridine) of the 4, 7- Dihydro-5-nitro-4-oximino-1, 3-dioxepins no one of the two possible dioxazocine were formed, but O- sulfonyl-derivatives of the oxyme were isolated. Under stronger rearrangement conditions (PCl5/CHCl3) the nitro-oxazinone derivative was isolated and its structure was elucidated by IR, 1H and 13C NMR spectroscopy) and MS spectroscopy. The influence of position of nitrogen and oxygen and of their lone electrone pairs on 13C chemical shifts and C-H coupling constants enables us to discuss on two possible structures of nitrooxazinones. The spectroscopic data will be correlated with the results of X-ray structure analysis.

4 ; 7-Dihydro-5-nitro-4-oximino-1 ; 3-dioxepins ; Beckmann rearrangement ; 1H and 13 C NMR spectra ; Chemical shifts ; Coupling constants ; X-ray

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