Eremophilane, Ishwarane

Recent additions to the eremophilane sesquiterpenoids include the petasol derivative (689),308 isofukinone (690),309 the noreremophilane (691),310 and the unique cyclopropenone derivative (692).311 This last compound also co-occurs 

Laudova, Z. Samek, K. Ubik, and L. Novotny, Coll. Czech. Chem. Commun., 1981, 46, 1048. 

Takahashi, K. Tori, I. Horibe and K. Kuriyama, J. Chem. Soc., Perkin Trans. 1, 1981, 2695. 

Reagents i, MCPBA ii, LiCH2NC iii, Me2SO-(COCl)2 iv, LiCsCMe v, A 

The biosynthesis of PR toxin (723), derived from Penicillium roqueforti, has been examined by incorporation of [l,2-13C2]acetate into the fungus.325 The labelling pattern as observed from the 13C n.m.r. spectrum is completely in accord with the original Robinson proposal involving a C-10, C-5 methyl migration from a eudesmane-type precursor, as has been demonstrated before. 

---

Rao et al. isolated ishwarone (391) as one of the chief constituents of the roots of A. indica [347], Subsequent investigations by Ganguly et al. and Govindachari et al. led to the first structural assignment of ishwarone (391) as a novel tetracyclic sesquiterpene ketone based on eremophilane skeleton, the first of its kind to occur in the nature [348,349]. Ishwarane (388), reported from the roots of A. indica by Govindachari et al. is the first tetracyclic sesquiterpene hydrocarbon based on the eremophilane skeleton [334], A tetracyclic sesquiterpene alcohol, ishwarol (389) is also reported from the roots of A. indica [350]. Pakrashi et al. isolated (125)-... 

---