The biosynthesis of phenols. Part XXIV. Arugosin C, a metabolite of a mutant strain of Aspergillus rugulosus

Abstract

Significant deviations in chemical shift values. t The multiplicity indicated is the result of off-resonance experiments.

Secoemestrin D, a Cytotoxic Epitetrathiodioxopiperizine, and Emericellenes A–E, Five Sesterterpenoids from Emericella sp. AST0036, a Fungal Endophyte of Astragalus lentiginosus1

“…Although the purified epimeric aldehydes 5 and 6 did not undergo any interconversion, it cannot be ruled out that only one of these is the genuine natural product and the other is an artifact formed as a result of epimerization during the isolation process (see Supporting Information, S27 ). Compounds 7 – 9 were identified as sterigmatocystin ( 7 ), 10 arugosin C ( 8 ), 11 and epiisoshamixathone ( 9 ) 12 respectively, by comparison of their low-resolution MS and NMR spectroscopic data with those reported. …”

“…AST0036, isolated from a healthy leaf tissue of Astragalus lentiginosus (spotted locoweed, Fabaceae) was found to be active in the resazurin (alamarBlue®) cell viability assay for cell proliferation/survival. 7 Bioactivity-guided fractionation of this extract provided a new epitetrathiodioxopiperizine, named secoemestrin D ( 1 ), and five new sesterterpenes, emericellenes A–E ( 2 – 6 ), together with sterigmatocystin ( 7 ), 10 arugosin C ( 8 ), 11 and epiisoshamixanthone ( 9 ) 12 of which 1 and 7 were found to be cytotoxic. Metabolites 2 – 6 contain a hitherto unprecedented bicarbocyclic sesterterpene molecular scaffold which we have named as emericellane skeleton.…”

The Oxidation of Organic Compounds by Active Manganese Dioxide

“…744 (303) was oxidized with freshly prepared active manganese dioxide in ether resulting in the ketone 306. Oxidation of IIX-hydroxyprevitamin 0 3 (304) with an active manganese dioxide resulted also in l-ketoprevitamin 0 3 (306). This oxidation.…”

“…The formation of l-ketoprevitamine (306) instead of l-ketovitamin 305 implied that the thermal equilibrium 306 ~ 306 is totally on the side of 306. differing thus from the equilibrium vitamin 0 3 ~ previtamin 0 3 which is predominant on the side of the vitamin. This shift in the position of the equilibrium is consistent with the increased stability due to the linearly conjugated carbonyl system present in the ketone 306 314 (Scheme 6).…”

Three Pairs of New Isopentenyl Dibenzo[b,e]oxepinone Enantiomers from Talaromyces flavus, a Wetland Soil-Derived Fungus

“…Up to now, about nine isopentenyl dibenzo[b,e] oxepinones had been reported from fungi in Nature, including arugosins A-D from Aspergillus rugulosus [1,2] and A. variecolor [3], arugosin G from Emericella nidulans var. acristata [4], pestalachloride B from Pestalotiopsis adusta [5], cephalanones D-E from Graphiopsis chlorocephala [6], and 1,6,10-trihydroxy-8-methyl-2-(3-methyl-2-butenyl)-dibenz[b,e]oxepin-11(6H)-one (CAS: 160585-91-1, 5) from Penicilium sp.…”