Acetone extracts of the mycelial cake of Streptomyces luteoreticuli Arai yield a new toxic, nitro-containing metabolite (I), C_<19>H_<19>HO_5, m.p. 184.5-185°, which was named luteoreticulin. Oxidation of (I) with potassium permanganate gave p-nitrobenzoic acid, and with alkaline hydrogen peroxide gave an acid (III), C_<13>H_<13>NO_4. The ethyl ester of (III) was identified with ethyl 2,4- dimethyl-5-(p-nitrophenyl)-2,4-pentadienoate prepared from the synthetic pathway by means of mixed m.p., UV, IR, and NMR. On the hydrogenation over Adams catalyst, (I) absorbed five moles of hydrogen to give (II). The IR and UV spectra of (II) indicate the presence of a 4-methoxy-2-pyrone moiety in (I). Hydrolysis of (I) with barium hydroxide in 50%-ethanol gave a diketone (VIII), which establishes the relative position of the substituted groups on the 4-methoxy-2-pyrone. On the basis of NMR studios of (I), (IV) and related compounds, geometric configuration of (I) was deduced to be trans-trans configuration. The structure (I)_c including the geometric configuration was established for luteoreticulin.
