Chemistry of Ecteinascidins. Part 5: An Additional Proof of Cytotoxicity Evaluation of Ecteinascidin 770 Derivatives.

ABSTRACT

Eleven 2'-N-acyl derivatives (5a-k) were prepared from ecteinascidin 770 (Et 770 1b) via known 18,6'-O-bisallyl-protected compound (3) in three steps. Their in vitro cytotoxicities were determined by measuring IC50 values against human cell lines HCT116 and DU145. 5-Isoxazolecarboylamide derivative (5i) and 4-methoxybenzoylamide derivative (5k) were found to be promising leads for further optimization.