Efficient microwave-assisted prenylation of pinostrobin and biological evaluation of its derivatives as antitumor agents

Pinostrobin (5-hydroxy-7-methoxyflavanone) obtained in relatively large amounts from fingerroot (Boesenbergia pandurata) was converted to its C-6 and C-8 prenylated derivatives. The Mitsunobu reaction, europium(III)-catalyzed Claisen–Cope rearrangement, and Claisen reaction coupled with cross-metathesis were used as the key steps. Using a sealed-vessel microwave reactor, the Mitsunobu and Claisen/Cope reactions occurred smoothly with short reaction times and in satisfactory yields. The target compounds and five new intermediary substances showed cytotoxic activity toward SK-BR-3, MCF-7, PC-3, and Colo-320DM human tumor cell lines, and all of them had significantly lower IC50 (μM) values than pinostrobin.

Pinostrobin (1) was converted to its prenylated or allylated derivatives (2–8) using a microwave reactor. All resulting compounds showed cytotoxic activity toward a panel of human tumor cell lines with significantly lower IC50 (μM) values than compound 1.Figure optionsDownload as PowerPoint slide