Of xylerythrins

This method allowed also the synthesis of xylerythrins (IV, Scheme 4b), through a Perkin-type condensation of the terphenylquinone with... 

Abrahamsson, S., and M. Innes Molecular Structure of Xylerythrin - a Fungus Pigment. Acta Chem. Scand. 19, 2246 (1965). 

Molecular Structure of Xylerythrin, a Fungus Pigment. Acta Crystallogr. 21,... 

In what amounts to a biogenetically patterned approach, a synthesis of xylerythrin (7 a) has been reported involving condensation between polyporic acid (100) and p-hydroxyphenylacetic acid (d) this Perkin-type reaction proceeds via the 4-oxo-2-enoic acid intermediate (101). 

In this section metabolites bearing one or more alkyl groups directly attached to the C-18 p-terphenyl core will be reviewed, including the xylerythrin group, which is originated through insertion of a third phenylpropanoid unit (See Section 5). 

Xylerythrin (155) and the other quinone methide pigments of P. sanguinea clearly have their biogenetic origins in the assembly of three phenylpropanoid units and therefore pose a question concerning... 

Despite the successful synthetic work of Gripenberg (329, 330), the obvious corollary that xylerythrin arises naturally by condensation between polyporic acid and (4-hydroxyphenyl)acetic acid (667) has so far found no support in labelling experiments. On the contrary, von Massow and coworkers (693, 695) have suggested that the dimeric intermediate may be a pulvinic acid and have subsequently supported their hypothesis with incorporation experiments using " C-labelled phenylalanine and tyrosine (690, 691, 694), as well as [ " C]-4-hydroxypulvinic acid (694). Their results suggest the pathway depicted in Scheme 29. 

According to this mode of biosynthesis, 4-hydroxypulvinic acid reacts further with phenylalanine (=phenylpyruvate) and with tyrosine ( = 4-hydroxyphenylpyruvate) to give xylerythrin (155) and peniophorin (159), respectively, with loss of the carboxyl group of the amino acid. The reasonable assumption that this same carbon atom is retained ultimately as the methylene group of the pyran ring during the biosynthesis of peniophorinin (161) is, however, rendered impossible if von Massow s observation that tyrosine is incorporated to the same... 

Incorporation of Phenylpropanes into Xylerythrin-Type Pigments in Peniophora sanguinea. Phytochem. 16, 1695 (1977). 

---