Central nervous system active compounds. XIII: The use of aminomethylene phthalides in the synthesis of phthalideisoquinoline alkaloids

Dimethylaminomethyleneisobenzofuranones react with alkoxyphenylethylamines in aqueous acidic solution to give phthalide isoquinolines (tetrahydroisoquinolinylisobenzofuranones) in moderate yields. N-Methylation gives the naturally occurring phthalideisoquinoline alkaloids. A number of examples of this reaction sequence are reported, including the synthesis of (±)-cordrastine, (±)-corlumine and (±)-adlumine.