Synthesis of <i>N</i>-substituted 3-(2-aryl-2-oxoethyl)-3-hydroxyindolin-2-ones and their conversion to <i>N</i>-substituted (<i>E</i>)-3-(2-aryl-2-oxoethylidene)indolin-2-ones: synthetic sequence, spectroscopic characterization and structures of four 3-hydroxy compounds and five oxoethylidene products
Acta crystallographica. Section C, Structural chemistry.