Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• cytotoxicity against P388 murine leukemia cells with IC50 values of 33 and 89 μM, respectively. Keywords: Actinomadura; nomimicin; polyketide; spirotetronate; Introduction Actinomycetes are a valuable source of bioactive compounds, accounting for approximately two thirds of all known antibiotics, and more

• medium, and the whole culture broth was extracted with 1-butanol. The extract was subjected to silica gel and ODS column chromatography, and the final purification was achieved by reversed-phase HPLC to yield two new spirotetronate polyketides, nomimicins B (1) and C (2), along with a known compound

• remaining four sp2 carbon atoms, C1, C2, C3, and C24, although only limited HMBC correlations H22/C24 and H25/C3 were available, a spirotetronate structure was assembled. This was in consideration of the high similarity of the 13C NMR chemical shifts of these carbon atoms to those for the corresponding

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• experiments and in vitro reaction with the purified enzyme (Scheme 23) [146]. Interestingly, homologs of vstJ are also present in the biosynthetic gene clusters of the spirotetronate-containing polyketides abissomycin C (148), tetrocarcin (150), quartromicin D1 (151), chlorothricin (152), lobophorin and