Interestingly, from the new series, compound 27 with a 2-methoxymethyl group and compound 28 with a 2-(3-hydroxypropoxy)methyl substituent at the benzofurane, showed antiproliferative activity against tumor and endothelial cells in the nanomolar range (IC50 = 8–31 nM), keeping full activity against P-glycoprotein overexpressing cells (A2780 AD). Here, ABCB1 is linked to neoplasm.