AMINE-INDUCED REARRANGEMENTS OF 2-BROMO-1-(1H-INDOL-3-YL)-2-METHYL-1-PROPANONES - A NEW ROUTE TO ALPHA-SUBSTITUTED INDOLE-3-ACETAMIDES, BETA-SUBSTITUTED TRYPTAMINES, ALPHA-SUBSTITUTED INDOLE-3-ACETIC ACIDS AND INDOLE BETA-AMINOKETONES

The reaction of 2‐bromo‐1‐(1H‐indol‐3‐yl)‐2‐methyl‐1‐propanone (1) and 2‐bromo‐1‐(1‐methyl‐1H‐indol‐3‐yl)‐2‐methyl‐1‐propanone (2) with primary amines proceeds in good yields to produce rearranged amides by a proposed pseudo‐Favorskii mechanism. These amides in turn can either be reduced to produce β‐substituted tryptamines or hydrolyzed to produce substituted indole‐3‐acetic acids. When the reaction is carried out using bulky primary or secondary amines, β‐aminoketones are produced by elimination of hydrogen bromide followed by Michael addition. When hindered secondary amines or tertiary amines are used, elimination to the α,β‐unsaturated ketones occurs. Copyright © 1990 Journal of Heterocyclic Chemistry