Abstract:
The present invention relates to the compounds of formula (I), wherein: R1 is hydrogen, hydroxy or amino; R2 is hydrogen, hydroxy, methoxy or methoxymethoxy; R3 is hydrogen, hydroxy, amino, methoxy, methoxymethoxy or, taken together with R2, methylenedioxy (also known as 1,3 dioxolo); R4 is hydrogen, hydroxy, methoxy, methoxymethoxy, benzyl, di(C¿1-4?)alkylaminomethyl or, taken together with R?3¿, methylenedioxy; R5 is hydrogen or hydroxy; provided that at least one of R1 through R5 is other than hydrogen; and i) X2 is hydroxy or methoxy with X?1, X3 and X4¿ being hydrogen or ii) X1 taken together with X2, X2 taken together with X3 or X3 taken together with X4, is methylenedioxy, provided that each of the remaining respective X?1, X2, X3 and X4¿ substituents are hydrogen, intermediates in the synthesis of them, pharmaceutical formulation containing them, their use as inhibitors of topoisomerase and their use in the treatment of tumors.