Enhanced antitumor properties of 3'-(4-morpholinyl) and 3'-(4-methoxy-1-piperidinyl) derivatives of 3'-deaminodaunorubicin

Reductive N,N-dialkylation of daunorubicin with 2,2'-oxydiacetaldehyde and NaBH3CN occurred in two steps without interruption and with cyclization to form 3'-(4-morpholinyl)-3'-deaminodaunorubicin. This derivative retained the antitumor efficacy of doxorubicin against mouse leukemia P388 but at one-fortieth the dose; hence, it is the most potent anthracycline analogue synthesized so far. The 4-methoxy-1-piperidinyl derivative, similarly prepared with 3-methoxyglutaraldehyde, showed improved efficacy against P388, though at normal doses. Results with a series of analogues indicate that incorporation of the N in the new ring and the presence of an ether O at the 4-position are critical for enhanced activity.