Camptothecin analogs and methods of preparation thereof

A compound having the formula

• in racemic form, enantiomerically enriched form or enantiomerically pure form;
• wherein R1 and R2 are independently the same or different and are hydrogen, —C(O)Rf wherein Rf is an alkyl group, an alkoxy group, an amino group or a hydroxy group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an acyloxy group, —OC(O)ORd, wherein Rd is an alkyl group, —OC(O)NRaRb wherein Ra and Rb are independently the same or different, H, —C(O)Rf, an alkyl group or an aryl group, a halogen, a hydroxy group, a nitro group, a cyano group, an azido group, a formyl group, a hydrazino group, an amino group, —SRc, wherein Rd is hydrogen, —C(O)Rf, an alkyl group or an aryl group;
• or R1 and R2 together form a chain of three or four members selected from the group of CH, CH2, O, S, NH, or NR15, wherein R15 is an C1-C6 alkyl group;
• R3 is H, a halogen atom, a nitro group, an amino group, a hydroxy group, or a cyano group;
• or R2 and R3 together form a chain of three or four members selected from the group of CH, CH2, O, S, NH, or NR15;
• R4 is H, F, an amino group, a C1-3 alkyl group, a C2-3 alkenyl group, a C2-3 alkynyl group, a trialkylsilyl group or a C1-3 alkoxy group;
• R5 is a C1-10 alkyl group, an alkenyl group, an alkynyl group, or a benzyl group;
• R6 is —Si(R8R9R10) or —(R7)Si(R8R9R10), wherein R7 is an alkylene group, an alkenylene group, or an alkynylene group;
• and R8, R9 and R10 are independently a C1-10 alkyl group, a C2-10 alkenyl group, a C2-10 alkynyl group, an aryl group or a —(CH2)NR11 group, wherein N is an integer within the range of 1 through 10 and R11 is a hydroxy group, an alkoxy group, an amino group, an alkylamino group, a dialkylamino group, a halogen atom, a cyano group, —SRc or a nitro group;
• R13 is H, F or —CH3;
• R16 is —C(O)Rf or H;
• and
• pharmaceutically acceptable salts thereof.