Concise synthesis and structure–activity relationship of furospinosulin-1, a hypoxia-selective growth inhibitor from marine sponge

Structure–activity relationship of furospinosulin-1 (1), a hypoxia-selective growth inhibitor isolated from marine sponge, was investigated. Concise synthetic method of 1 was developed, and some structurally modified analogues were prepared. Biological evaluation of them revealed that the whole chemical structure was important for the hypoxia-selective growth inhibitory activity of 1. Among prepared, the desmethyl analogue 30 showed excellent hypoxia-selective inhibitory activity similar to that of 1 and also exhibited in vivo anti-tumor activity with oral administration.