Atromentin and Derivatives

An alternative mechanism for degradation of leucomentin-3 to the acetate (31) of (-h)-osmunda lactone would involve initial acid catalysed addition of acetic acid to the epoxide followed by intramolecular displacement of the hydroquinone moiety and would lead, significantly. 

The structures of the flavomentins and spiromentins were determined using mainly H-n.m.r. spectroscopy (365). Interestingly, in the H-n.m.r. spectra of the monoacylated terphenylquinones (33), (34), and (35) (among others) the protons of the two aryl residues appear to be equivalent due to a rapid acyl shift between the oxygen atoms in the quinonoid ring (364). 

The distribution and some properties of the flavomentins and spiromentins are summarised in Table 6 (365). 

Pigment Occurrence Colour on TLC TLC Rf Ultraviolet/Vis. [ max qualitative, ethanol] 

Flavomentin-B (35) Paxillus atrotomentosus, P. panuoides var. ionipus Orange 0.44 266, 371 nm 

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