Synthesis and cytotoxicity of leinamycin antibiotic analogues.

A simple synthesis of 1,2-dithiolan-3-ones from alpha,beta-unsaturated thiophenyl esters is reported. Introduction of the biologically active 1,2-dithiolan-3-one-1-oxide moiety of leinamycin into aldehydo-d-arabinose 11, the uridine derivative 16, and the deoxythymidine 21 was established. An extended bioactive part of leinamycin carrying a carbon-carbon triple bond was also synthesized. All of these analogues of leinamycin showed cytotoxic activity against HeLa3 tumor cells. Interestingly, the lipophilic, silyl group-containing derivatives proved to be more active than the hydrophilic counterparts.