Synthesis and characterization of 4,6-dimethylbenzofurans; challenges in benzofuro[3,2-c]quinolines formation

In this study, 4,6-dimethylbenzofurans were synthesized via the conden­sation reaction of 3,5-dimethylphenol with various α-bromoa­cetophenone derivatives in the presence of Al2O3. The resulting dimethylbenzofurans were then subjected to a Vilsmeier-Haack reaction, leading to selective formylation at the C3 position. Schiff base formation with hydroxylamine was successfully achieved for all benzofuran carbaldehydes, affording the corresponding aldoximes. The attempted synthesis of benzofuro[3,2-c]quinolines through benzoylation and cyclization of the related benzofuran aldoximes is also described.