Indolenine Oxides, VIII. Reaction of 5,7‐di‐ tert ‐butyl‐3,3‐dimethyl‐3 H ‐indole 1‐Oxide with Grignard Reagents. – A New Stable Aminyl Oxide (Nitroxide)

The title compound 1 , unsubstituted at C‐2, is efficiently converted into its 2‐substituted derivatives 4a , b by Grignard addition and lead dioxide oxidation. 4a , when subjected to the same sequence, gives high yields of the aminyl oxide 5a which is also formed in small amounts in the conversion of 1 together with two other minor compounds. The course of the reaction is influenced by the presence of a bulky tert ‐butyl group at C‐7 in 1 and by the solvent used for the Grignard reaction.