A New Route For The Synthesis Of (-)-Demethylmedicarpin

Pterocarpans are devrivatives of isolfaconoids found widely in natural plants,which have a variety of biological activities. Pterocarpans are one of the activeingredients in many herbal medicines. Domestic and foreign chemical scientistssuccessfully extracted and separated all kinds of pterocarpins, and tested theiractivities, including anti-bacterial activity, anti-fungal activity, anti-microbial activity,anti-HIV-1activity, anti-infection activity, anti-plasma activity, anti-snake venomactivity, hepatoprotective activity and anti-oxidant activity. So far, chemical scientistsstudied their total syntheses and proposed some synthetic strategies.Our desired synthetic compound is (-)-demethylmedicarpin. On the basis ofreported literature, we proposed a new total synthetic route that is the most simple ofresorcinol as starting material to obtain the7-methoxychromene via acetylation,cyclization and methylation reactions. And then, the7-methoxychromene can beconverted into the (S)-7-methoxychromenol via chiral reduction in the presence ofCBS catalyst. However, in this reduced step, we failed to obtain the chiral reduceddesired product. Thus, after many attempts, we decide to change our original totalsynthetic strategy. Firstly, we try to synthesize isoflavones which will be reduced intothe chiral product in the presence of CBS catalyst. Finally, the (-)-demethylmedicarpincan be obtained via dehydration condensation and Lewis-acid-demethoxylation. Thecompounds were determined by1H NMR and13C NMR spectra.