M. Kinugawa et al., LARGE-SCALE SYNTHESIS OF THE HIGH-QUALITY INDOLOQUINONE ANTITUMOR AGENT EO-9 VIA [BIS(TRIFLUOROACETOXY)IODO]BENZENE OXIDATION OF 4-AMINOINDOLE, Synthesis, (5), 1996, pp. 633
A convenient large scale preparation of the indoloquinone antitumor ag
ent EO 9 (1) has been developed. The hazardous reagent, Fremy's salt,
was replaced by a safer one, [bis(trifluoro acetoxy)iodo]benzene, for
oxidation of the 4-aminoindole 3 to the corresponding indoloquinone 4,
and high quality 1 was easily obtained by choosing acetonitrile as th
e reaction solvent for substitution of the methoxy group with ethyleni
mine to introduce the aziridinyl group into EO 7 (6).