Carbamate derivatives of betulinic acid and betulin with selective cytotoxic activity

Carbamate derivatives of betulinic acid and betulin were synthesized and tested against fifteen tumor cell lines. The most active compounds 9 (bis(ethylcarbamate)betulin) and 11 (3-O-ethylcarbamate of 28-O-acetylbetulin) were found to be selectively cytotoxic towards tumor cell lines, inducing apoptosis by activation of caspase 3.