Synthesis and biological activities of NB-506 analogues: Effects of the positions of two hydroxyl groups at the indole rings

In the course of a study of 6-N-amino-substituted analogues of NB-506 (1), a more potent anticancer drug, J-109,404 (2), in which the formyl group of NB-506 was replaced with a 1,3-dihydroxypropane group, was reported. A stud y of further modification in the positions of two hydroxyl groups at the in dole rings of 2 resulted in the discovery of a 2,10-dihydroxy analogue, J-1 07,088 (3), which is a promising anticancer agent with a broader therapeuti c window than J-109,404. (C) 1999 Elsevier Science Ltd. All rights reserved .