Equisetin, an antibiotic from Fusarium equiseti NRRL 5537, identified as a derivative of N-methyl-2,4-pyrollidone.

Ophiosetin, a new tetramic acid derivative from the mycopathogenic fungus Elaphocordyceps ophioglossoides

“…Equisetin (2) and all related compounds that have been tested so far show potent antibacterial activity against Gram-positive bacteria. [1][2][3][4] Consistent with previous reports, in our assay, compounds 2 and 3 exhibited antibacterial activity against Gram-positive S. aureus (MIC 4 mg ml À1 for both 2 and 3) and E. faecalis (MIC 4 mg ml À1 for 2 and 2 mg ml À1 for 3). In addition, compounds 2 and 3 also showed moderate activity against Gramnegative E. coli (MIC 8 mg ml À1 ).…”

Epi-trichosetin, a new undecaprenyl pyrophosphate synthase inhibitor, produced by Fusarium oxysporum FKI-4553

“…Careful comparison enabled us to conclude that 1 was the epimer of 2 at C-5 0 . Several structurally related compounds, such as equisetin (3), 11 paecilosetin (4), 12 and phomasetin (5), 13 were isolated from fungal strains belonging to the genera Fusarium, Phoma and Paecilomyces, respectively ( Figure 6). All compounds having a tetramic acid moiety are known to show a variety of biological activities, such as antimicrobial activity, 14 phytotoxic activity 15 and inhibitory activity of HIV integrase.…”

Synthetic strategies toward the decalin motif of maklamicin and related spirotetronates

“…Similar correlations have been observed in related equisetin derivatives. 21 In a similar manner, compounds 21 and 23 were identified as exo adducts since they displayed a NOESY signal between the protons at C10 and C5 as expected in a cis -decalin motif (marked with a red arrow in Scheme 3). Compound 21 displayed additional correlations between: (a) the C4 methyl and protons at C7 axial and C9 axial ; and (b) protons at C13 and C5 (marked in blue arrows in Scheme 3).…”

“…Similar correlations have been observed in pyrrolocin B, a compound that contains a cis -decalin with an equatorial methyl at C8. 21a …”