The IR spectra of O. Ol M solutions of the bases (I-XXIII) in chloroform showed the presence of intramolcule hydrogen bonding (IBH) between the hydrogen on the amide nitrogen and the amino-group [5]. The strength of the IHB is shown by the considerable shift in the absorption for stretching vibrations of the NH group (AVNH), amounting for example to 175 cm-~ in (VIII). The substituents at the amine nitrogen, by virtue of their negative inductive ...