SYNTHESIS OF BIOACTIVE COMPOUNDS FROM ABUNDANT NATURAL PRODUCT .13. THE SYNTHESIS AND ANALGESIC PROPERTIES OF NEW SPIROISOCHROMANYL ACID-DERIVATIVES SYNTHESIZED FROM NATURAL SAFROLE

We describe in this paper the synthesis of a new xycyclopentane-1,1-(6 ,7-methylenedioxy)isochroman] and a oxycyclohexane-1,1-(6,7-methylened ioxy)isochroman] acids 11 and 12, obtained from natural safrole (7), i solated from sassafras oil. These derivatives were obtained in high ov erall yield using a synthetic route in which was observed brevity and appreciable diastereoselectivity in the intramolecular regioalkylation of the 6-position of the aromatic system of the natural starting mate rial, the key step of the synthetic route representing a variable in t he well-known Friedel-Crafts reaction. The new acids, derivatives 11 a nd 12, were obtained in ca 74% and 78% overall yield. They show a good analgesic profile in the pharmacological assay, the test in mice abdo minal contortion.