Alkynyl-substituted camptothecins and process for their preparation

A pharmaceutical composition, which comprises an effective amount of an alkynyl-substituted camptothecin of formula (I)

• wherein R1 is selected from the group consisting of:
• hydrogen;
• an optionally substituted C1-C6 alkyl;
• C3-C7 cycloalkyl;
• C3-C7 cycloalkyl C1-C6 alkyl;
• an optionally substituted phenyl;
• an optionally substituted naphthyl;
• —Rx—NR3R4, wherein Rx is C1-C4 alkylene, R3 and R4 are, each independently, hydrogen, C1-C6 alkyl phenyl, or benzyl;
• —(Ry)m—COOR5, wherein m is zero or 1, Ry is C1-C4 alkylene, R5 is hydrogen, C1-C6 alkyl, C3-C7 cycloalkyl or phenyl C1-C6 alkyl;
• —(Rz)n—COR6, wherein n is zero or 1, Rz is C1-C4 alkylene, R6 is C1-C6 alkyl, C3-C7 cycloalkyl, phenyl C1-C6 alkyl, an optionally substituted phenyl, or —NR7R8, wherein R7R8 are, each independently, hydrogen or C1-C6 alkyl;
• and
• SiR9 R10R11, wherein R10 and R11 are, each independently, C1-C4alkyl;
• R2 is selected from the group consisting of:
• hydrogen;
• C1-C6 alkyl;
• C3-C7 cycloalkyl;
• and phenyl C1-C6 alkyl;
• X is selected from the group consisting of:
• alkanoyloxy;
• benzoyloxy;
• amino;
• hydroxy;
• nitro;
• chlorine;
• and a methylene- or ethylene-dioxy group linked to positions 10 and 11 of the molecule;
• or a pharmaceutically acceptable salt thereof as an active principle for treatment of tumors, in association with one or more pharmaceutically acceptable carriers and/or diluents.