The structures of two alkaloids of Balfourodendron riedelianum, balfourodine and isobalfourodine, as well as two of their isomeric transformation products,+ balfourodine and $-isobalfourodine, have been determined. These compounds repre-sent the four possible isomeric linear and angular dihydrofuro-and dihydropyrano-quinolones corresponding to 2- alkoxy-4-quinolones and 4-alkoxy-2-quinolones. Through the use of synthetic compounds ...