Isomerism in the series of acetoacetamide cyanoacetylhydrazones

Acetoacetamide cyanoacetylhydrazones in the crystal state and in a DMSO sol ution exist as equilibrium mixtures of stereoisomeric forms due to conforma tional and geometric isomerism. The equilibrium in the hydrazone tautomer i s almost independent on the nature and position of substituent in the amide fragment. The EE'E" conformer always predominates.