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

摘要

We describe in this paper the synthesis of a new spiro[2-carboxycyclopentane-1,1-(6,7-methylenedioxy)isochroman] and a spiro[2-carboxycyclohexane-1,1-(6,7-methylenedioxy)isochroman] acids 11 and 12, obtained from natural safrole (7), isolated from sassafras oil. These derivatives were obtained in high overall 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 material, the key step of the synthetic route representing a variable in the well-known Friedel-Crafts reaction. The new acids, derivatives 11 and 12, were obtained in ca 74% and 78% overall yield. They show a good analgesic profile in the pharmacological assay, the test in mice abdominal contortion. [References: 18]