Alberto Giménez

Dihydroanthracenones from Dermocybe splendida and related fungi

Abstract (3 S )-Atrochrysone and (3 S )-torosachrysone have been isolated from Australian toadstools belonging to the genus Dermocybe ; labelling experiments show that sodium [2- 13 C]acetate and [Me- 13 C]methionine are efficiently incorporated into torosachrysone by intact fruit bodies.

Pigments of fungi. Part 38. Synthesis of austrocorticinic acid and (S)-(–)-austrocorticin; absolute stereochemistry of natural austrocorticin

The absolute configuration of the fungal anthraquinone (+)-austrocorticin 1 is established as (R) by synthesis of its antipode 5 from (S)-(–)-but-3-yn-2-ol via a Diels–Alder reaction involving the highly functionalised, chiral butadiene 6. Similarly, austrocorticinic acid is made available from but-1-yne.

Austrovenetin, the principal pigment of the toadstool Dermocybe austroveneta☆

Abstract Fruit bodies of the fungus Dermocybe austroveneta produce the novel dimeric anthracenone pigment austrovenetin which has been isolated and characterized after extraction and purification in the absence of oxygen and light. Austrovenetin is the precursor of skyrin and hypericin found in extracts of D. austroveneta under normal laboratory conditions.

Pigments of fungi, part 19. A degradative method for the determination of central chirality in naturally occurring 3-hydroxy-3-methyl-3,4-dihydroanthracen-1(2H)-ones: Application to pigments of the flavomannin type.

Abstract The absolute stereochemistry at both chiral centres in the flavomannin-6,6′-di- O -methyl ethers A 1 ( 23 ) and B 1 ( 24 ) si determined as ( R ) by chemical correlation over six steps without the need for intermediate purification with methyl ( S )-(−)-tetrahydro-2-methyl-5-oxo-2-furanetate ( 25 ); the methodology is developed using the fungal metabolite ( S )-torosachrysone ( 2 ) as an initial substrate.

A degradative method for the determination of central chirality in naturally occurring 3-hydroxy-3-methyl-3,4-dihydroanthracen-1(2H)ones.

Abstract Torosachrysone ( 2 ) is correlated over six steps without the need for intermediate purification with methyl R -(+)-tetrahydro-2-methyl-5-oxo-2-furanacetate ( 16 ); the method is applicable in principle to a large number of more complex dihydroanthracenones of as yet indeterminate stereochemistry.

The dermocanarins, unique macrocyclic lactones from the fungus dermocybe canaria

Abstract The dermocanarins I ( 3 ) and II ( 4 ), unique coupled octaketides containing a nine-membered lactone bridge, have been isolated from the mycelium of the fungus Dermocybe canaria and their structures determined by spectroscopic methods.

Pigments of fungi. Part 17. (S)-(+)-dermochrysone, (+)-dermolactone, dermoquinone, and related pigments; new nonaketides from the fungus Dermocybe sanguinea(sensu Cleland)

The novel dihydroanthracenones (8), (11), and (12), and the biogenetically related anthraquinones (13), (14), and (15) have been isolated from fruit bodies of the Australian toadstool Dermocybe sanguinea(sensu Cleland). The absolute stereochemistry of dermochrysone (8) is inferred by chiroptical comparison with fungal dihydroanthracenones of known chirality. Feeding experiments show that sodium [1-13C] acetate is efficiently incorporated into dermochrysone (8) and dermolactone (13) by intact fruit bodies.

Prenylated Acylphloroglucinols with Leishmanicidal Activity from the Fern Elaphoglossum lindbergii.

Purification of a diethyl ether extract of the Argentinian fern Elaphoglossum lindbergii afforded five new prenylated acylphloroglucinols, lindbergins E-I (1-5), of which two showed significant in vitro leishmanicidal activity against promastigotes of Leishmania braziliensis and L. amazonensis. The structures of compounds 1-5 were elucidated based on analysis of their spectroscopic data and comparison with values previously reported for other phloroglucinol derivatives isolated from plant species of the genera Hypericum, Dryopteris, and Elaphoglossum. Fragmentation and rearrangement patterns of prenylated acylphloroglucinols were analyzed, and some mechanisms were proposed to rationalize the peaks observed in the mass spectra of these natural products produced by EI and FAB. Compounds isolated from E. lindbergii show the opposite absolute configuration when compared to those reported from E. crassipes. Empirical evidence indicates that acylphloroglucinols carrying a prenylated acylfilicinic acid residue possess a high-amplitude configuration-dependent Cotton effect centered at 350-360 nm in their CD curves, from which the absolute configuration of the sole chiral center of the prenylated acylfilicinic acid moiety can be deduced.

Pigments of fungi. Part 40. Dermocanarins 1–3, unique naphthol- and naphthoquinone-anthraquinone dimers that contain a macrocyclic lactone ring from the fungus Dermocybe canaria Horak

The dermocanarins 4–6 are unique naphthylanthraquinones containing a nine-membered lactone ring that have been isolated as the principal pigments of the subterranian mycelium of the fungus Dermocybe canaria and their structures determined by spectroscopic methods. In the fruit bodies of this fungus physcion 8-O-β-D-glucopyranoside 12 accompanies the aglycone 1 as the major colouring matters.

New trihydroxylated tetrahydroanthraquinones from fungi of the genus Dermocybe

Abstract The pigments 6 , 7 and 8 , the first trihydroxylated tetrahydroanthraquinones from Basidiomycetes, have been isolated from an Australian toadstool belonging to Dermocybe ; the absolute stereochemistry of each pigment is established by synthesis.