Semisynthesis of Forsyshiyanine A and a Derivative with Significant Anti-Pancreatic Cancer Activity

Forsyshiyanine A (8), a trinorditerpene alkaloid isolated from Forsythia suspensa exhibiting in vitro anti-inflammatory and antiviral activities, has been synthesized for the first time from trans-communic acid (12a) and labdane cupressic acid (13). Furthermore, a series of derivatives were efficiently prepared and screened for cytotoxic activities against five human tumoral cell lines. Derivative 25 showed cytotoxicity (IC50 = 6.5 μM) against the Mia PaCa-2 pancreatic cancer cell line, making it an interesting candidate for future structure–activity relationship (SAR) investigations.