Synthesis of Schiff bases of benzofuran with potential biological activity

Reduction of 5-methoxy-6-formyl(Ia)- and 5-formyl-6-methoxy-2,3-diphenylbenzofuran (IVa) yielded 6- and 5-methyl derivatives Ib and IVb, respectively. Oxidation, hydrolysis and demethylation of Ib and IVb gave 2,2-dihydroxy-4-methyl-)IIc)-and2,4-dihydroxy-5-methylbenzofuran )Vc). The carboxamides Ie and IVe were obtained from the oximes Ic and IVc via the cyano derivatives Id and IVd. By condensation of the aldehydes If, IVf and VII with primary amines the corresponding Schiff bases (IIIa--c, VI and VIIIa--f) were obtained. The antibacterial activity of the Schiff bases and previously prepared benzofuran derivatives were investigated.