The Senecio alkaloids. The structure and absolute configuration of isoline
Abstract
The structure and absolute configuration of the alkaloid isoline has been determined by showing that its acid portion, isolinecic acid, is (2S,3R,5S)-5-ethyl-2,5-dihydroxy-2,3-dimethylhexanedioic acid (1). The stereochemistry was defined by degradation of the acid to 3-methylheptane-2,5-dione (4) of known absolute configuration.