Oximes of isatins

Since the Pfitzinger reaction requires a large excess of alkali, aliphatic aldehydes, which readily polymerize under these conditions, cannot be used in the reaction. However, it was possible to overcome these difficulties by using the aldoximes. Thus, Pfitzinger heated the isatin 7 with acetaldehyde oxime in the presence of potassium hydroxide in water and obtained 4-quinolinecarboxylic acid together with the oxime of isatinic acid 196 [175],... 

In a novel transformation the j8-oximes of isatins gave o-N, N -dimeth-ylaminomethyleneaminobenzonitriles (13) with the Vilsmeier reagent (Me2NCHO—POCI3), The nitriles were cyclized to 4-aminoquinazolines with ammonium acetate in 70-80% yields. ... 

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