Synthetic study toward pareirubrine B

Abstract

Pareirubrine B, isolated from the roots of Cissampelos pareira(Menuspermaceae) was reported to display antileukemic activity. And total synthesis of pareirubrine B have not been reported yet up to date. The concise synthesis of pareirubrine B precursor has been achieved by utilization of the anionic radical coupling of a prepared phenolic nitronate. The required phenol was introduced by Pd-mediated coupling reaction, and the nitromethyl group was introduced on the bottom part of the molecule by Reissert-type addition. The bottom part of the molecule, isoquinoline was constructed by Pomerantz-Fritsch isoquinoline synthesis. The overall yield of pareirubrine B precursor from a commercially available starting material (isovanillin) was 22% in 13 steps.