TOTAL SYNTHESIS OF AN ANALOGUE OF SCHIZANDRIN

A schizandrin analogue 9,1,2,3, 10, 11,12-hexamethoxy-6, 7-dihydroxy-cis-6, 7-dimethyl dibenzocyclooctadiene, is one of the metabolites of schizandrin with comparable anti-convulsion activity. In this paper, compound 9 was synthesized from gallic acid through the following sequence of reactions: methylation, Henry condensation, reduction with Fe—FeCl₃—HCl, intermolecular reductive coupling and intramolecular nonphenolic oxidative coupling, totally in seven steps. The intermediate 1, 4-diaryl-2, 3-dimethyl-2, 3-butanediol (7) which is a mixture of erythro and threo isomers was converted by DDQ in TFA into compound 9 and another new compound 10 via a different reaction path.