New approach towards cytotoxic furyl macrolactones by ring closing metathesis.

Furan-2-ylalkenols 2a-d were esterified with undec-10-enoyl chloride and the resulting esters were cyclized to unsaturated 2- and 3-furyl macrolactones by ring closing metathesis using Grubbs catalyst I. Hydrolysis of the macrolactone 4b with NaOH led to the furylalkenoic acid and reaction of 4c with tert-butyllithium gave a tert-butyl ketone. Some of the resulting compounds were tested in the MTT assay for their cytotoxic activities against HL 60 cells and at the National Cancer Institute (NCI) against 60 cancer cell lines. The compounds only showed cytotoxic activities in the muM range.