Spectroscopic Studies on 4‐Nitrophenylhydrazones of Secondary and Tertiary α‐Ketoamides4‐Nitrophenylhydrazones of secondary and tertiary α‐ketoamides both exist in two stable isomeric forms (E/Z) with respect to the position of the substituents at the CN‐Bond. But whereas the Z‐form of the secondary amides can be easily assigned by means of intramolecular hydrogen bond, this criterion in case of most the derivatives of tertiary amides fails. As shown by derivatives of glyoxylic acid this deviation is evidently caused by steric facts due to the double substituted amide group and the alkyl residue