Diplophyllum albicans

X-Ray crystallographic analysis has led to a revised cycloaromadendrane structure for (-)-myliol (619), a metabolite of the liverwort Mylia taylorii ° cf. Vol. 4, p. 135 Vol. 6, p. 90). More recent investigations have resulted in the isolation of an isomeric compound, (—)-dihydromylione A (620) from the same source. Independent studies have also revealed the widespread occurrence of a closely related hydrocarbon, anastreptene (177), in the essential oils of various liverworts Anastrepta oveadensis, Diplophyllum albicans, Barbilophozia species) cf. p. 

Albicanol (66), a drimane-type sesquiterpene, was isolated from the liverworts Diplophyllum albicans [30] and also from the dorid nudbranch Cadlina luteomarginata [31] together with its acetate (67) which exhibits potent fish antifeedant activity. 

Liver mosses the chemistry of liver mosses has been studied intensively during the past years. Among the volatile components, a range of terpenoids, often with a unique structure, have been reported [12]. (—)-Bicyclogermacrene has been identified as a constituent of various liverworts such as Plagiochila asplenioides, Diplophyllum albicans, wA Mylia species [13]. 

Cw-a-bisabolene (241) and its trans-xsomQX (242) are present in Scapania species (2). ( —)-P-Bisabolene (234) has been isolated from Diplophyllum albicans 281). 

An independent investigation of the metabolites of American Diplophyllum albicans and D. taxifolium resulted in isolation of diplophyllin (355), a double bond isomer of (356), and 9a-acetoxydiplophyllin (361) 281). The stereostructure of (355) was based on spectroscopic evidence ( H-NMR and CD) and synthesis of ewNdiplophyllin (397) from isoalantolactone (396) by the acid-catalyzed reaction shown in Scheme 47. -diplophyllolide (398) was also obtained 281). The attachment of the acetoxyl group of (360), whose CD curve was quite similar to that of (355) to C-9 was suggested by a doublet at 5.04 ppm (/=9.7) and a doublet of doublets at 4.35 ppm (7=8.4, 10) due to the lactone methine. The stereochemistry at C-9 was based on analysis of H-NMR spectra of (360) and its dihydro- and tetrahydro derivatives, and on comparison of the spectral properties with those of (355) and related lactones. 

Benesova, V., Z. Samek, and S. Vasickova Structure of the Sesquiterpenic Lactone Diplophyllolide and Other Components from Diplophyllum albicans (L.) Dum. Collect. Czech. Chem. Comm. 40, 1966 (1975). 

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