AbstractDioxolides, a novel class of secondary metabolites were detected by a HPLC‐diode array screening technique in the culture filtrate ofStreptomyces tendaeTü 4042. The compounds show no biological activity against Gram‐positive and Gram‐negative bacteria, yeasts and fungi. Besides dioxolides, which consist of an unusual substituted dioxolane ring, anhydroshikimate andpara‐hydrobenzamide were detected by this technique. Both compounds were not yet described as natural