Polyporic acid synthesis

Among the early synthetic works, we wish to mention here the synthesis of polyporic acid (3) [115] and thelephoric acid (82) [78]. As summarised in Scheme 3a, several terphenylquinones have been synthesized with moderate yields starting from 2,5-dichlorobenzoquinone by arylation with V-nitrosoacetanilides or diazonium salts and subsequent alkaline hydrolysis. This method allowed preparation of symmetrical and unsymmetrical terphenylquinones, this latters with low yields. 

H. rutilans (Figure 9). Studies in rats showed that polyporic acid induced the same symptoms as had been seen in human beings which presumably reflect the reduced synthesis of uridine triphosphate (UTP). Treatment requires supportive therapy with restoration of electrolyte balances and dialysis for renal insufficiency. 

The discovery that polyporic acid (11) exhibits antileukemic activity (146) induced the synthesis of numerous analogues (148, 149, 150). The pigment also causes contraction of isolated rabbit ileum suspended in oxygenated Tyrode solution (395). Similarly, atromentin (13) shows significant smooth muscle stimulant activity (638) and proves to be an effective anticoagulant (226, 409). Polyporic acid lacks this latter property completely (409). 

The structures of phlebiarubrone (23) and its dihydroxy derivative (25) were confirmed by synthesis involving methylenation of the potassium salts of polyporic acid (11) and atromentin (13), respectively, with methylene sulphate in the presence of sodium bicarbonate (22,... 

Structure (155) for xylerythrin was confirmed by synthesis involving a Perkin-type condensation between polyporic acid and (4-hydroxy-phenyl)acetic aicid (329). This reaction, performed in acetic anhydride... 

Synthesis of the Pigments of the Polyporic Acid Series by the Use of A-Nitrosoace-tylarylamines. J. Pharmac. Soc. Japan 62, 195 (1942). 

Polyporic acid series. J Chem Soc 1041-1045 Cambie RC (1968) The depsides from Stereocaulon ramulosum (Sw.) Rausch. N Z J Sci 11 48-53 Canonica L, Rindone B, Santaniello E, Scolastico C (1972) A total synthesis of mycophenolic acid, some analogues and some biogenetic intermediates. Tetrahedron 28 4395-4404... 

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). 

The red-violet pigment in the lower cortex of some Sticta and Pseudocy-phellaria species is polyporic acid (104), the structure of which has been proven by synthesis. 

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