OXIDATION OF 1-ACYLINDOLES WITH MOLYBDENUM PEROXO COMPLEX (MoO<sub>5</sub>·HMPA): PREPARATION OF 1-ACYL-<i>trans</i>- AND<i>cis</i>-2,3-DIHYDROXYINDOLINE DERIVATIVES
Oxidation of 1-acylindoles with MoO5·HMPA in methanol gave a mixture of 1-acyl-trans- and cis-2,3-dihydroxyindoline derivatives in good yields, while 1-acyl-2-substituted indole was oxidized to a corresponding 2-hydroxyindoxyl.
Reaction of 3-hydroxy-2-methoxyindoline (4) with the amide acetal (5) gives 4-carbamoylmethyl-indoline (7) and -indole (8), which are converted into 4-(2-aminoethyl)indole (10) by treatment of the indoline (7) with hydrogen chloride followed by sodium hydroxide to form the indole (8), and then by reduction of the indole (8) with lithium aluminium hydride.