Leinamycin, an antitumor antibiotic isolated from Streptomyces sp., shows a 1,2-dithiolan-3-one 1-oxide heterocycle that appears to be involved in the biological activity. Several derivatives related to 1,2-dithiolan-3-one 1-oxide have been prepared and their activity as antineoplastic agents have been investigated. The synthesized compounds did not display a significative antitumor or cytotoxic activity in vitro.