Investigation into the regiochemistry of some isoxazoles derived from 1,3-dipolar cycloaddition of 4-nitrobenzonitrile oxide with some dipolarophiles: A combined theoretical and experimental studies

Reaction of 4-nitrobenzonitrile oxide(2) which was generated in situ with acrylo nitrile (3), methyl methacrylate (4) and allyl bromide (5) as dipolarphile afforded the new 7a, 8a and 9a compounds respectively. Reactivity and regiochemistry of these reactions were investigated using activation energy calculations and density functional theory (DFT)-based reactivity indexes. The theoretical 13C NMR chemical shifts of the cycloadducts which were obtained by GIAO method were comparable with the observed values.

Graphical abstract.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► 4-Nitrobenzonitrile oxide reacted with some dipolarphiles to afford new compounds. ► We study regiochemistry of reactions by activation energy and DFT reactivity indexes. ► Theoretical 13C NMR shifts of cycloadducts are comparable with observed values. ► The results obtained clearly predict the regiochemistry of the isolated cycloadducts.