Pseudocyphellaria amphisticta

Two naturally occurring ozonides, gilvanol (213) from Quercus gilva and adian-5-ene ozonide (214) from the leaves of Adiantum monochlamys, °° have been isolated. Their structures were readily confirmed by the action of ozone on hop-17(2l)-en-3jS-ol and adian-5-ene respectively. Amphistictinic acid (215), from the lichen Pseudocyphellaria amphisticta, is 15a-acetoxy-22-hydroxy-hopan-24-oic acid. The structure of the 6a,7a,22-trior previously reported from the lichen P. mougeotiana has been revised to 6a,7/3,22-tri-hydroxyhopane (216). The Tlj8,22-dior isolated from the same source has been shown to be a mixture of 7/8,22- (217) and 15a,22-dihydroxyhopane (218). 

A new hopane derivative, amphistictinic acid (488), has been isolated from Pseudocyphellaria amphisticta (273). The structural assignment followed principally from H-n.m.r. and mass spectral data and was confirmed by chemical conversion to hopane-15a,22-diol. 

Ronaldson, K. J., and A. L. Wilkins The Structure of Amphistictinic Acid a Triterpenoid Constituent of the Lichen Pseudocyphellaria amphisticta. Austral. J. Chem. 31, 215 (1978). 

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