Basicity, Lipophilicity, and Lack of Receptor Interaction of N‐Aminoalkylbenzamides and N‐Aminoalkyl‐o‐anisamides as Model Compounds of Dopamine Antagonists

N‐Aminoalkylbenzamides and N‐aminoalkyl‐o‐methoxybenzamides have been prepared and examined for their pKa, log P and dopamine receptor affinity. The pKa values range from ca. 7.5 for the derivatives having a one‐C‐atom side‐chain, to ca. 10.3 for the N‐aminobutyl derivatives. These variations with chain length are satisfactoryly explained by a field model. The variations in (log P)‐values as a function of chain length and substitution at the N‐atom indicate the involvement of proximity and conformational effects. The complete inability of the compounds to displace 3H‐spiperone and 3H‐sulpiride from their specific rat striatal binding sites demonstrates the critical role of adequate aromatic substitution at positions 4 and 5.