Raymond L. Edwards

Metabolites of the higher fungi. Part 21. 3-Methyl-3,4-dihydroisocoumarins and related compounds from the ascomycete family xylariaceae

Culture solutions of members of the ascomycete family Xylariaceae produce a series of 5-substituted 8-hydroxy-3-methyl-3,4-dihydroisocoumarins as major metabolites. Ramulosin, iso-ochracein, and mellein are produced by three Hypoxylon species and 4-hydroxy iso-ochracein by one species. The antibiotic pyrenophorin is produced by Nummularia broomeiana. The synthesis of 7-formylmellein from mellein is described and the products from the alkaline rearrangement of 5-formylmellein are studied spectroscopically.

Biosynthesis of the fungal polyketide, cubensic acid from Xylaria cubensis.

Abstract The biosynthetic origin of cubensic acid (1) from Xylaria cubensis is reported. Analysis of this metabolite suggests a modular polyketide assembly with an underlying biogenetic basis.

Metabolites of the higher fungi. Part 19. Serpenone, 3-methoxy-4-methyl-5-prop-1-enylfuran-2(5H)-one, a new γ-butyrolactone from the fungus Hypoxylon serpens(Barrons strain)(Persoon ex Fries)Kickx

Culture solutions of the fungus Hypoxylon serpens(Barrons strain) contain a new butyrolactone as the major metabolite, which has been identified as 3-methoxy-4-methyl-5-prop-1-enylfuran-2(5H)-one (2), and small quantities of the reduced analogue, 3-methoxy-4-methyl-5-propylfuran-2(5H)-one (3); the structures have been established by synthesis of compound (3). A new rapid synthesis of the isomeric 4-methoxy-3,5-disubstituted analogues is described and the two groups of compounds are compared spectroscopically.

Metabolites of the higher fungi. Part 29. Maldoxin, maldoxone, dihydromaldoxin, isodihydromaldoxin and dechlorodihydromaldoxin. A spirocyclohexadienone, a depsidone and three diphenyl ethers: keys in the depsidone biosynthetic pathway from a member of the fungus genus Xylaria

2-(3′-Chloro-2′-hydroxy-4′-methoxy-6′-methoxycarbonylphenoxy)-6-hydroxy-4-methylbenzoic acid (dihydromaldoxin 1), 2-(3′-Chloro-4′-hydroxy-2′-methoxy-6′-methoxycarbonylphenoxy)-6-hydroxy-4-methylbenzoic acid (isodihydromaldoxin 2), dechlorodihydromaldoxin 3, a new chlorinated depsidone (maldoxone 4) and a new spirocyclohexadienone (maldoxin 5) have been isolated from the culture medium of an as yet unidentified Xylaria species. The structures have been determined by physical and chemical methods and the positions of the substituents in dihydromaldoxin 1 have been confirmed by a single crystal X-ray structure determination. Their role in the grisan–depsidone biosynthetic pathway is discussed.

Metabolites of the higher fungi. Part 24. Cytochalasin N, O, P, Q, and R. New cytochalasins from the fungus Hypoxylon terricola Mill

Punctaporonin B, cytochalasin C and D, and five new cytochalasins have been isolated from the culture medium and mycelium of the fungus Hypoxylon terricola. Cytochalasin C is the major metabolite. Cytochalasin N is the 5,6-epoxide of cytochalasin C, and cytochalasins O and P are two epimeric 6-hydroxy analogues. Cytochalasin Q is a 6,7-epoxide and R is a 6,7,13,14-diepoxide. The epoxides formed by cytochalasin C and D are described and the acid- and BF3-induced rearrangement products of cytochalasin N are identified.

Constituents of the higher fungi. Part XII. Identification of involutin as (–)-cis-5-(3,4-dihydroxyphenyl)-3,4-dihydroxy-2-(4-hydroxyphenyl)-cyclopent-2-enone and synthesis of (±)-cis-involutin trimethyl ether from isoxerocomic acid derivatives

Xerocomic and isoxerocomic acids have been synthesised and converted into the corresponding 2,5-diaryl-4-methoxycyclopent-4-ene-1,3-diones. Reduction of the dione from isoxerocomic acid has given racemic involutin trimethyl ether (IV); this identifies involutin as (III). Isoxerocomic acid is readily oxidised to xerocomorubin; this is compared with the naturally occurring variegatorubin.

Metabolites of the higher fungi. Part 23. The punctaporonins. Novel bi-, tri-, and tetra-cyclic sesquiterpenes related to caryophyllene, from the fungus Poronia punctata(Linnaeus:Fries) Fries

Six new sesquiterpenes have been isolated from the culture medium of the fungus Poronia punctata. Punctaporonins A, D, E, and F are isomeric allylic alcohols possessing a tricyclic carbon skeleton not previously found in nature. Punctaporonin B is a related trihydroxycaryophyllene isomer, and punctaporonin C is a novel tetracyclic hemisuccinate. An additional major metabolite has been identified as (E)-methyl 3-(4-methoxyphenoxy)propenoate.

Metabolites of the higher fungi. Part 26. Cubensic acid, 3,7,11,15-tetra hydroxy-18-(hydroxymethyl)-2,4,6,10,14,16,20-heptamethyldocosa-4E,8E,12E,16E-tetraenoic acid, a novel polysubstituted C22 fatty acid from the fungus Xylaria cubensis(Mont.) Fr. with substituents and substitution pattern similar to the macrolide antibiotics

Cubensic acid, 3,7,11,15-tetrahydroxy-18-(hydroxymethyl)-2,4,6,10,14,16,20-heptamethyldocosa-4E,8E,12E,16E-tetraenoic acid, has been isolated from the mycelium and culture medium of Xylaria cubensis. Cytochalasin D is an additional metabolite isolated from the culture medium. The structure of cubensic acid has been determined by a combination of spectroscopic and chemical methods. A possible biosynthetic link between cubensic acid and certain macrolide antibiotics is suggested.

Constituents of the higher fungi. Part XIV. 3′,4′,4-Trihydroxypulvinone, thelephoric acid, and novel pyrandione and furanone pigments from Suillus grevillei(Klotsch) Sing. [Boletus elegans(Schum. per Fries)]

Eight crystalline pigments have been isolated from the fungus Suillus grevillei. 3′,4′,4-Trihydroxypulvinone, a novel pyrandione, and a novel furanone are described, and thelephoric acid is identified as the cap skin pigment of Suillus grevillei var. badius

Constituents of the higher fungi. Part XVI. Bulgarhodin and Bulgarein, novel benzofluoranthenequinones from the fungus Bulgaria inquinans(Fries)

Three crystalline quinones have been isolated from the fungus Bulgaria inquinans. Two of these have been identified as derivatives of benzo[j]fluoranthene and the third characterised as 4,9-dihydroxyperylene-3,10-quinone. This is the first recorded isolation of a natural product with structure based on the benzofluoranthene nucleus.