Simple Synthesis of 1,3,4,5-Tetrahydropyrrolo[4,3,2-de]quinoline and 5-Hydroxy-4-nitroindole (Synthetic Study for Indoles Having a Nitrogen Containing Functional Group at the 4-Position)

Abstract

A simple four (or three) step synthesis method for 1,3,4,5-tetrahydropyrrolo[4,3,2-elquinoline ( 5 ) from indole-3carboxaldehyde ( 9 ) is developed.A single step preparation of 5hydroxy-4-nitroindole ( 8 ) by the oxidation of 4-arnlnoindole (1-6) 1 s also reported.Discorhabdins (I) , 2 prianosins (2) ,3 batzellins (!) ,4 plakinidins (4-) , 5 and dehydrobufotenin ( ! 1 6 , ' are biologically active natural products and involve a 1,3,4, 5-tetrahydropyrrola[4,3,2-~lquinoline nucleus as a common structure (Figure 1).In