Stoffwechselprodukte von Mikroorganismen, XXXI [1]. Duricaulinsäure, ein neuer Naturstoff vom Phthalimidin-Typ aus Aspergillus duricaulis / Metabolie Products of Microorganisms, XXXI [1]. Duricaulic Acid, a New Natural Product of the Phthalim idine Type from Aspergillus duricaulis

Abstract

<jats:p>Duricaulic acid (1), a new nitrogen containing metabolite was isolated from Aspergillus </jats:p><jats:p>duricaulis and its structure established. <jats:sup>1</jats:sup>H and <jats:sup>13</jats:sup>C NMR of some phthalimidines are discussed.</jats:p>

The taxonomy, biology and chemistry of the fungal Pestalotiopsis genus

“…104 It appeared in the NMR spectrum as a mixture of two inseparable atropisomers due to the hindered internal rotation, which indicated a non-enzymatic biosynthesis or a particularly facile mode of racemization and was confirmed by X-ray crystal structure analysis. The structure of 33 differs significantly from those known alkaloids [105][106][107][108][109] by having a relatively rare 2,4-dichloro-5-methoxy-3-methylphenol moiety connected to the isoindolin-1-one core structure, and it displayed potent antifungal activity against Fusarium culmorum with an IC 50 value of 0.89 mM. Surprisingly, compound 33 can be easily converted under almost neutral conditions from the marine antibiotic pestalone, 110 a chlorinated and highly functionalized benzophenone produced by a marine fungus of the genus Pestalotia, and the total synthesis of pestalone has been achieved in only 10 steps with an overall yield of 16% starting from commercially available orcinol.…”

Marilines A–C: Novel Phthalimidines from the Sponge‐Derived Fungus Stachylidium sp.

“…Compounds with a related phthalimidine (isoindolinone) nucleus as found for 1 – 3 are known from fungal metabolism, however, they all lack the methyl group at C8. The structurally most simple phthalimidines possess an unsubstituted nitrogen atom as found in mariline C ( 3 ), namely 6‐hydroxy‐4‐methoxy‐5‐methylphthalimidine (cichorine),2, 3 zinnimidine,4 duricaulic acid,29 memnobotrin A and the related stachybotrylactam30 and the more complex xylactam 31. Reported N‐substituted phthalimidines include compounds with a phenylethyl,13, 32 ethyl‐1‐ol,6, 7 or a carbonic acid9, 12 moiety attached.…”

Fungal phthalimidines-chemodiversity, bioactivity and biosynthesis of a unique class of natural products

“…This genus has also been identified as producer of various phthalimidines-derivatives. For example the first phthalimidine, duricaulic acid (1) was isolated in 1985 from Aspergillus duricaulis (Achenbach et al 1985). Although phthalide analogues of compound 1 from the same fungus were identified as antimicrobial, however, no such activity was reported for compound 1.…”