Bisabolane, Sesquicarane

A large number of oxygenated bisabolane sesquiterpenoids (53)—(71) have been isolated and identified by Bohlmann s group (see also ref. 342). A third 

Reagents i, MeOjPlOCHCO Me ii, BuLi-TMEDA iii, CO iv, MeOH-H v, Chrom. vi, 

Masaki, K. Hashimoto, K. Sakuma, and K. Kaji, J. Chem. Soc., Chem. Commun., 1979, 855. 

Reagents i, PhSCl ii, Et3N iii, MeCOaH iv, (MeO)3P v, Mn02 vi, NaOAc vii, A viii, PTSA-AcOH ix, OH  

Spectroscopic evidence has been used to deduce the structures of iso-sesquicarene (97) and the derivative of sesquisabinene (98) isolated from Haplopappus tenuisectus and Arctotis grandis respectively. Two isoprenylogues of a-phellandrene, namely the methyl esters of 3,4-dihydronidorellaurin acid (99) and nidorellaurin (100), have been identified in Nidorella auriculata DC.  

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