STUDIES ON INDIAN MEDICAL PLANTS .42. STEROL AND TARAXASTANE DERIVATIVES FROM ARTEMISIA-ANNUA AND A RATIONAL APPROACH BASED UPON C-13 NMR FOR THE IDENTIFICATION OF SKELETAL TYPE OF AMORPHANE SESQUITERPENOIDS

3 beta-Acetoxy-taraxer-14-ene (taraxeryl acetate) and a crystalline su bstance have been isolated front the hexane extracts of the roots of A rtemisia annua. The crystalline substance has been found to be a mixtu re of beta-sitosterol and stigmasterol from its C-13 NMR spectral data . For the establishment of skeletal type of amorphane sesquiterpenoids naturally occurring in A. annua, the chemical shifts of the C-4, C-5 and C-6 resonances are found to be of crucial significance.