Lecidea lithophila

A number of well-known depsides were synthesised in the manner described above (777), as well as the recently reported compounds 2-0-methylperlatolic acid (241), 2 -0-methylperlatolic and 2 -0-methylanziaic acid (777). An earlier report of the isolation of the related depside, 4-0-demethylplaniaic acid (257) from Stereocaulon ramulosum (41) appears to be an error (84). However this depside has now been shown to co-occur with planiaic acid (258) in the lichens Lecidea lithophila and L. plana (84). The structure of (257) was indicated by microhydrolysis experiments and confirmed by comparison with synthetic material. The synthetic route to (257) is outlined in Scheme 30, and is typical of the approach to all thepara-orcinol depsides. 

O-Demethyl- OMe H OH H CsHn H OMe CO2H CsHn H Lecidea lithophila Crystallization Microhydrolysis, 84,... 

Isol. from Lecidea plana and L. lithophila. Needles (MeOH). Mp 110-111°. 

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See also in sourсe #XX -- [ , ]

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