New tetracyclic 1,4-oxazepines constructed via practically simple tandem condensation strategy from readily available synthons

A streamlined synthetic methodology towards novel tetracyclic 1,4-oxazepines from readily available precursors is described. The compounds, designed as more soluble version of the earlier described, poorly soluble dibenzo[b,f][1,4]oxazepines, were obtained in high yields and as a single regioisomer as a result of three tandem chemical events—nucleophilic aromatic substitution, Smiles rearrangement and denitrocyclization.