Antitumor activity of new morpholino anthracyclines

Antitumor activity of 3'-deamino-3'-morpholino anthracyclines was examined. Morpholino derivatives of 13-deoxocarminomycins, MX2 (1), MX (2) and MY5 (3) shown in Fig. 1, administered iv showed increase in life span (ILS) values over 110% against ip-inoculated P388 leukemia. The ranges of effective doses of these compounds were broader than those of their parent drugs. The morpholino derivatives of doxorubicin and carminomycin, however, were not so effective as their parent drugs. Among these compounds, MX2 administered orally showed nearly the same effects as those obtained by iv administration against P388 leukemia. MX2 administered iv showed 89% ILS against intracerebrally-inoculated L1210 leukemia. The highly lipophilic nature of MX2 could contribute partly to achieving chemotherapeutic responses against intracerebrally-inoculated tumors or by oral administration.