合成路线1

The title compound is synthesized starting from the natural isoflavone formononetin (I). Esterification of (I) with pivaloyl chloride (II) affords pivalate (III). Catalytic hydrogenation of (III) in the presence of Pd/BaSO4 leads to the chromane derivative (IV). The Grignard reagent (VI), prepared from 4-(benzyloxy)benzyl chloride (V), is then condensed with ketone (IV) to furnish the tertiary alcohol (VII). The O-benzyl protecting group of (VII) is then removed by catalytic hydrogenolysis to afford phenol (VIII). Alkylation of (VIII) with N-(2-chloroethyl)piperidine (IX) and K2CO3, with simultaneous pivalate ester hydrolysis, leads to the piperidylethyl ether (X). The tertiary alcohol of (X) is finally dehydrated by means of HCl in acetonitrile to provide the target compound (1,2).