A NEW SYNTHETIC ROUTE TO THE AZOCINO[4,3-B]INDOLE CORE STRUCTURE

The reaction of 2 with 2-methoxyethylamine in the presence of ZnCl2 af forded imine 3, which was reduced with NaBH4 to amine 4 without isolat ion. After deprotection of the carbonyl function by treatment with ben zeneseleninic anhydride, ketone 5 was converted to compound 6 with 2-o xobutyric acid and dicyclohexylcarbodiimide. The isodasycarpidone deri vative 7, formed by aldol reaction of 6, represents a tetracyclic subs tructure of strychnos-type alkaloids.