Synthesis and Biological Evaluation of Antitumor‐Active Arglabin Derivatives

Abstract Arglabin derivatives varied at the endo‐ or exo‐cyclic double bond were synthesized and studied in a colorimetric sulforhodamine B assay for their cytotoxicity. Variations on the endocyclic double bond led to compounds of reduced cytotoxicity whereas derivatives from the reaction of the α‐methylene‐γ‐butyrolactone moiety led to compounds of similar or only slightly reduced cytotoxicity but different, cell line‐dependent selectivity. In addition, arglabin is an excellent starting material for the synthesis of the guaianolide arborescin.