Synthesis of nοvel artemisinin dimers with polyamine linkers and evaluation of their potential as anticancer agents.

•Artemisinin was modified at position 10 or 11 with linkers bearing a hydroxyl group.•Urethane-type conjugates of modified artemisinins with polyamines were synthesized.•Conjugation resulted in more efficient compounds in inhibiting MCF7 cell growth.•The most active compounds (e.g. 9, 12) did not induce ROS production or apoptosis.•They inhibited angiogenesis in vivo and in vitro.