The CON−H^…+NH₂ Blue-Shifting H-Bond Stabilizing Effect on Z Secondary Amides and Cyclic System Conformational Rearrangement through an Alkylamine-Chain Migration Pathway

Figure 2

Fragmentary IR spectra in the solid state for infrared active secondary amides 2 and 4 with reference to 8 (in order from the top). The model, which took into account the out-of-plane N-H wagging provided a blue shift. The shift of the vibration bands varies between several tens of wavenumbers. The blue shift vibrational frequencies have proved to be a very sensitive indicator of the strength of the intramolecular H-bond.