Novel Benzotropolone and 2H-Furo[3,2-b]benzopyran-2-one Pigments fromTricholoma aurantium (Agaricales)

  title={Novel Benzotropolone and 2H-Furo[3,2-b]benzopyran-2-one Pigments fromTricholoma aurantium (Agaricales)},
  author={D{\"o}rte Klostermeyer and Liliana Knops and Tilman Sindlinger and Kurt Polborn and Wolfgang Steglich},
  journal={European Journal of Organic Chemistry},
The bright orange-red color of the toadstool Tricholoma aurantium is due to the benzotropolone pigment aurantricholone (1). The compound is at least partially present as the calcium salt. Minor pigments are the yellow 2H-furo[3,2-b]benzopyran-2-one derivatives aurantricholides A (7a) and B (7b), which exhibit strong green fluorescences. Their structures have been established by total syntheses. 
Syntheses of 3,4-benzotropolones by ring-closing metatheses.
Hydrolysis of the dimethyl ketal moiety and enolization provided the 3,4-benzotropolones and this access comprises 4-6 steps and totaled a 22-81% yield.
Structural Revision and Biomimetic Synthesis of Goupiolone B.
In this study, the structure of goupiolone B was revised on the basis of DFT calculations of the 13 C NMR chemical shifts and biosynthetic considerations and it was suggested that the compound was produced by oxidative coupling between catechol and goupiola, which was strongly supported by biomimetic synthesis.
1. Tetronic Acids
Tetronic acids belong to the class of 4-hydroxybutenolides that are characterized by a 4-hydroxy-2(5H)-furanone ring, as it can be seen in the generic structure of Scheme 1.1 [1]. This type of
Regioselective Bromination of Benzocycloheptadienones for the Synthesis of Substituted 3,4-Benzotropolones Including Goupiolone A.
Coupling with excess phenylboronic acid and ketal hydrolysis provided the diphenylated benzotropolone 56 and suggests a strategy, by which the natural bispulvinone aurantricholone might be reached.
Secondary Metabolites Isolated from Tricholoma Species (Basidiomycota, Tricholomatacee): A Review
This review is the first complete report about the secondary metabolites isolated to date from the fruiting bodies of Tricholoma (Fr.) Staude, with the exclusion of most volatile constituents.


Spectral evidence for the structure of three flavanotropolones related to theaflavin, an orange-red pigment of black tea
Conclusive spectral evidence for the structure of categallin (V), pyrogallin (VI), and erycetin (VIII), three flavanotropolones related to theaflavin (I) and purpurogallin (IX), is presented. The
Neuartige Diterpenoide aus den Ritterlingen Tricholoma aurantium und T. fracticum (Agaricales)
Novel Diterpenoids from the Toadstools Tricholoma aurantium and T. fracticum (Agaricales)1 Two novel diterpenoids trichaurantin (1) and its 6-O-acetyl derivative 2 have been isolated from
Pigments of Fungi. XV. An Efficient, Unambiguous Route to Unsymmetrically Substituted Dibenzyl Acyloins and Their Use in the Synthesis of Fungus Pigments of the Pulvinone and Grevillin Types
Dibenzyl acyloins including those bearing unsymmetrically disposed aryl residues are assembled in high yield by reaction between the O-trimethylsilyl ethers of arylacetaldehyde cyanohydrins and
Tannins and Related Compouns. XXXVI. : Isolation and Structures of Theaflagallins, New Red Pigments from Black Tea
A chemical examination of black tea polyphenols had led to the isolation of three new red pigments, spitheaflagallin 3-O-gallate (1), epitheaflagallin (2) and theaflagallin (3), together with the
1H and 13C NMR assignment of theaflavin, theaflavin monogallate and theaflavin digallate
Theaflavin, theaflavin monogallate and theaflavin digallate were isolated from black tea leaves and studied by 1D and 2D NMR techniques, thus allowing unambiguous assignment of the 1H and 13C
Studies on the Mechanism of the Oxidation of Tea Leaf Catechins
Oxidations of epigallocatechin in the presence of catechol or pyrogallol with tea oxidase as well as with an oxidizing reagent and the isolation of the oxidation products, categallin (II) and
Zur Kenntnis der o‐Chinone, XXIV. Synthese, Struktur und Eigenschaften von 1′.2′‐Dihydroxy‐6.7‐benzotropolonen
1′.2′-Dihydroxy-benzotropolon-Derivate konnen nach zwei Methoden dargestellt werden: 1.aus 3 Moll. eines o-Benzochinons mit unsubstituierter Doppelbindung und 1 Mol. eines geeigneten