The characterization, total synthesis and antiprotozoal activities of novel bichalcones from Rhus pyroides

Rhus pyroides is a tree which is resistant to attack by common pests including the corn cricket. Early investigations were directed to determining if anti-feeding metabolites were present in the plant [1]. As part of our effort to look for anti-protozoal substances we obtained from the leaves of the same plant novel O-linked chalcone dimer (1) and the previously unknown C-C coupled dimer (2) [2]. We also reported on the synthesis of the O-linked dimers (achieved through application of the Ullmann coupling of appropriately substituted chalcone moieties), and their antiproliferative properties. We have now concluded an investigation that culminated in the total synthesis of the C-C linked dimers from simple and available resorcinol and 4-hydroxybenzaldehyde and have also determined their antiprotozoal and cytotoxic properties. Key steps included the solvent-free syntheses of chalcones, and the first application of the Suzuki-Miyaura coupling reaction in the synthesis of bichalcones. The present work constitutes a general method for the rapid syntheses of a number of rhuschalcone VI related bichalcones. The synthesis and biological properties will be presented.

References: [1] Masesane, I.B. et al. (1999) Phytochemistry 53:1005–1008.

[2] Mdee, L.K. et al. (2003)J. Nat. Prod. 66:599–604.