Synthesis of Ecteinascidin analogues from Cyanosafracin B: isolation of a kinetically stable quinonimine tautomer of a 5-hydroxyindole
P. A. Ceballos, M. Pérez, C. Cuevas, A. Francesch, I. Manzanares, A. M. Echavarren
Eur. J. Org. Chem. 2006, 1926-1933
Abstract: Phthalimido derivatives of cyanosafracin B have been synthesized as analogues of the antitumor agent ecteinascidin 743. As part of this study, a quinoneimine has been prepared, which is a kinetically stable tautomer of a 5-hydroxyindole. This quinoneimine tautomer is stable under acidic and mild basic conditions.