Fusidane Lanostane Group

The structure of helvolic acid has been revised to (13). The ring b acetoxy-group is at C-6 and not at C-7 as was previously suggested. As a result, a similar modification must be made to the structures of helvolinic acid, 7-deacetoxyhelvolic acid, and 7-oxofusidic acid. The two interesting double bond isomers (14) and 

Several new halothurinogenins have been reported. Djerassi and his colleagues isolated s temaygenin (19), koellikerigenin (20), and seychellogenin (21) by acid 

Holothuria polii. The non-conjugated dienes stichopogenins Ai (31) and A, (32) have been reported from trepang, the far-eastern sea cucumber. 

Kanematsu and S. Natori, Chem. Pharm. Bull. Japan), 1970, 18, 779. 

Wehrli, and K. Schaifner, Chem. Comm., 1969, 852. 

Yamamura and Y. Hirata, in Alkaloids , ed. K. Wiesner, M.T.P. International Review of Science, 

Organic Chemistry Series Two, Volume 9, Butterworths, London, 1976, p. 161. 

Reagents i, BuLi-Pr2NH-6-methyIhept-5-enoic acid ii, CH2N2 iii, Ac20-py iv, POCl3-py 

In an approach to the stereocontrolled creation of the acyclic side-chain of tetracyclic triterpenoids and other natural products, Trost and his colleagues have converted the acyclic starting compound (29) into the cyclopropanoid intermediate (31) via the diazo-ketone (30). The key step in the scheme is the cleavage of the cyclopropane with lithium dimethylcuprate to give (32). The stereochemistry at C-7 is determined by the configuration of the double bond in (29). The c.d. and u.v. spectra of a series of triterpenoid olefins have been measured. The Scott-Wrixon rules can be used to correlate the sign of the c.d. curves with molecular structure. A 

Photolysis of the imidazolide (33) of 3j8-acetoxy-25,26,27-trisnorlanost-8-en-24-oic acid to give (34) has the advantages of simpler experimentation and higher 

Further new natural products are (38) from the toxic micro-organism Fusarium sporotrichioides 921,30 (39) and (40) from olive oil,31 triphyllol (41) from Adeno-phora triphylla (Campanulaceae),32 and cyclonervilol (42) and cyclohomonervilol (43) from Nervilia purpurea (Orchidaceae). The structure of (43) was supported by its conversion into cycloeucalenol.33 Two new xylosides from Cimicifuga japonica (Ranunculaceae) are based on the genuine sapogenins (44) and (45). Treatment of 

The seed oil of Cucumis sativus (Cucurbitaceae) contains (51) and (52) in addition to other known 4 x-methyl compounds.39 Momordicosides A—E from the seeds of Momordica charantia (Cucurbitaceae) are based on the sapogenins (53)—(56). The structure and stereochemistry of compound (53) were established by X-ray analysis.40 These cucurbitacins are notable for the absence of an oxygen function 

The bark of Rhus javanica (Anacardiaceae) contains rhuslactone (57), a novel dammarane-type triterpenoid with an a-oriented side chain. The structure followed 

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