a thiazole containing macrolide characterized by an unusual 1,3-dioxo-1,2-dithiolane moiety that is spiro fused to an 18 member macrolactam ring; isolated from Streptomyces; MF C22-H26-N2-O6-S3; possible DNA alkylator; the leinamycin biosynthetic gene cluster from Streptomyces atroolivaceus S-140 consists of two polyketide synthases genes