Syntheses, spectroscopic and crystallographic characterizations of 4-nitrobenzyloxy derivatives and benzofurans from ortho-substituted benzaldehydes and 4-nitrobenzyl bromide

A series of benzyloxybenzaldehyde derivatives (1-3) were prepared by the reactions of 4-nitrobenzyl bromide with 4-hydroxy-3-methoxybenzaldehyde (vanillin), 2-hydroxy-3-methoxybenzaldehyde (o-vanillin) and 2-hydroxy-4-methoxybenzaldehyde. When the reaction time is quite long, benzofuran derivatives (4 and 5) were obtained by the reactions of ortho-hydroxyaldehydes with the 4-nitrobenzyl bromide. Condensation reactions among the three benzyloxybenzaldehyde derivatives (1-3) with 2-aminomethylfuran (furfurylamine) yielded the new imine compounds (6-8). The structures of these aldehydes (1-3), benzofuran derivatives (4 and 5) and imine compounds (6-8) were confirmed on the basis of elemental analyses, IR, (1)H NMR and (13)C NMR and mass spectroscopy. The solid-state structures of compounds 4-6 were determined by single-crystal X-ray crystallography.