2-Ethyl-5-(3-indolyl)oxazole from Streptomyces cinnamomeus discovered by chemical screening. Characterization and structure elucidation by X-ray analysis.

In the lipophilic extracts from Streptomyces cinnamomeus 2-ethyl-5-(3-indolyl)oxazole (1a) was detected by chemical screening methods. The structure of the crystalline 1a was determined by spectroscopic and X-ray analysis. The new mono- and dibromo derivatives 1b and 1c are described. 1a is identical with pimprinethine and belongs to a group of microbial indole alkaloids, which can be regarded as masked tryptamine derivatives.