Nitrogen-based camptothecin derivatives

A compound of the formula:

• wherein R is RaRbN—(CH2)m, m is an integer from 1-10, and each of Ra and Rb is independently
• phenyl optionally substituted with from one to five substituents independently selected from the group consisting of halo, lower alkyl, lower alkoxy, hydroxy, cyano, nitro, amino, halogenated lower alkyl, halogenated lower alkoxy, formyl, lower alkyl carbonyl, hydroxycarbonyl, lower alkylcarbonyloxy, benzyloxy, optionally substituted piperidino, lower alkoxycarbonyl, and lower alkylcarbonylamino;
• cycloalkyl of 3-7 carbons, optionally substituted with one to five substituents independently selected from the group consisting of halo, lower alkyl, lower alkoxy, hydroxy, cyano, nitro, amino, halogenated lower alkyl, halogenated lower alkoxy, hydroxycarbonyl, lower alkoxycarbonyl, lower alkylcarbonyloxy, and lower alkylcarbonylamino;
• lower alkoxy;
• or
• RaRb together with N form a cyclic amine or imide ring;
• and
• R2 is —CH2NR7R8 (where R7 and R8 together with N are cyclic amino), butoxyiminomethyl, hydrogen, or together with R3 is —CH2(NR12R13)—CH2—CH2— (where R12 and
• R13 each is independently hydrogen or lower alkyl);
• R3 is hydrogen, trialkylsilylethylene or together with R2 is —CH2(NR12R13)—CH2—CH2— (where R12 and R13 each is independently hydrogen or lower alkyl);
• R4 is hydrogen, lower alkyl or together with R5 is ethylenedioxy;
• R5 is hydrogen, halo or together with R4 is ethylenedioxy;
• and
• R6 is hydrogen,
• wherein:
• if R2 is —CH2NR7R8 (where R7 and R8 taken together with —N— represent a cyclic amino) then R3 and R6 are H and R4 and R5 taken together represent ethylenedioxy;
• if R2 is butoxyiminomethyl then each of R3, R4, R5 and R6 is H;
• if R2 is hydrogen then R3 is trialkylsilylethylene and each of R4, R5, and R6 is H;
• and
• if R2 and R3 together represent —CH(NR12R13)—CH2—CH2— then R4 is lower alkyl, R5 is halo, and R6 is H, wherein R12 and R13 each is independently H or lower alkyl.