Synthesen von Indolen mit (2‐Aminoäthyl)‐, (2‐Aminopropyl)‐oder Alkanolamin‐Seitenketten am Sechsring. 5. Mitt. über synthetische Indol‐Verbindungen [1]

Abstract 4‐, 5‐, 6‐ and 7‐cyanoindoles are converted in excellent yields into the corresponding formylindoles by sodium hypophosphite/nickel according to the method of BACKEBERG and STASKUN. Condensation of these formylindoles with nitromethane or nitroethane affords the related nitrovinyl‐indoles, which are reduced to the aminoalkyl‐indoles quoted in the title by means of lithium aluminium hydride. On the other hand, 5‐chloroacetyl‐indole is aminated by reaction with various secondary amines, and the aminoketones formed are reduced to the corresponding 5‐(2‐amino‐1‐hydroxy‐alkyl)‐indoles. Condensation of 1‐acetyl‐7‐hydroxy‐indoline with chloroacetyl chloride according to FRIEDEL‐CRAFTS yields the 1‐acetyl‐4‐chloroacetyl‐7‐hydroxy‐indoline, which is transformed into indoline derivatives carrying a 2‐amino‐1‐hydroxyethyl side‐chain in position 4.