RING-OPENING AMINOLYSIS OF SESQUITERPENE LACTONES - AN EASY ENTRY TO BIOACTIVE SESQUITERPENE DERIVATIVES - SYNTHESIS OF (-BETA-CYPERONE AND(-)-EUDESMA-3,5-DIENE FROM SANTONIN())

Santonin (1) and other sesquiterpene lactones (2-3) react with pyrroli dine and other cyclic secondary amines to afford gamma-hydroxyamides, which by elimination with mesyl chloride in pyridine-benzene at 80 deg rees C give unsaturated amides 4a-4c, 5a-5c and 6. Starting from amide s 5a-5c a series of bioactive compounds against Locusta migratoria hav e been prepared, differing in the oxidation states of the C-3 and C-12 carbon atoms. Starting from amides 5a and 6 two conjugated diene eude smanes (+)-beta-cyperone (15) and (-)eudesma-3,5-diene (19) have been prepared involving an elaboration of the amide group of the side chain of the eudesmane skeleton. Copyright (C) 1996 Elsevier Science Ltd