N-alkoxy-2-aryl-2-hydroxycarboxamides 3 are smoothly converted into 3-
alkylsubstituted 1-alkoxyindolin-2-ones (2A) by dicyclohexylcarbodiimi
de in boiling trichloroethene. The acidolysis of the 1-tert-butoxyindo
lin-2-ones 2Ab, g, i, k as well as the 1-alkoxy-methoxyindolin-2-ones
2Ac, h, j affords the corresponding 1-hydroxyindolin-2-ones 2B in good
yields.