A study on the contribution of the 1-phenyl substituent to the molecular electrostatic potentials of some benzazepines in relation to selective dopamine D-1 receptor activity.

The molecular electrostatic potentials for a selective dopamine D-1 receptor antagonist, 7-chloro-8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-methylbenzazepine (SCH 23390 (1], and a selective dopamine D-1 receptor agonist, 7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SK&F 38393 (2], have been calculated in order to obtain an understanding of the nature of the interactions between the phenyl ring and the receptor. Analogues of 1 with conformationally constrained phenyl rings have also been studied. Based on this study, the conclusion is drawn that an important part of the interaction between the phenyl ring in the benzazepines and the receptor is due to electrostatic forces, and that the phenyl ring interacts with the same receptor site as the oxygen atom of the 8-hydroxy group.