ANNOTININE: THE LACTONE RING

The action of lithium aluminum hydride in dioxane solution on annotinine reduces the lactone and gives rise to a dihydroxy ether while the same reaction in tetrahydrofuran causes scission of the cyclic ether as well and produces a trihydroxy compound. The same trihydroxy compound is also obtainable by the similar reduction of annotinine chlorohydrin. Treatment of the trihydroxy compound with thionyl chloride converts it to a chlorine-containing sulphite ester which under the action of chromous chloride yields an unsaturated dihydroxy compound A, while under the conditions of the Clemmensen reaction, it yields an isomeric unsaturated dihydroxy compound B. Annotinine reacts with phenyl-lithium to give what seems to be a tetrahydroxy compound (C28H35O4N) which is oxidized by chromic acid to C28H33O4N. These reactions lead to two conclusions: (a) that hydrochloric acid and lithium aluminum hydride open the cyclic ether of annotinine in the same way, and (b) that the hydroxyl involved in the lactone is tertiary.