Synthesis and Optical Properties of Alkaloid Quindoline, Its Structural Analogues and Substituted δ‐Carbolines

Abstract Alkaloid quindoline, its structural analogues and δ‐carbolines were obtained through the Cadogan reaction using DPPE under solvent‐free conditions as a key stage of the synthesis. Various o ‐nitroarylpyridines prepared by one‐pot synthesis from nitroacetophenones, methyl orthoformate and acetoacetic ester enamine were used as starting materials for the preparation of δ‐carbolines. 2‐Aryl‐3‐nitro‐5,6,7,8‐tetrahydroquinolines obtained by reacting 2‐hydroxymethylenecyclohexanone with nitroacetophenones enamines were used for the synthesis of quindoline and its structural analogs. A relationship between the structure and optical properties of the synthesized compounds was found.