2-Haloaporphines as potent dopamine agonists

Abstract

The synthesis of 2-amino- and 2-halo-substituted aporphines is described. The key step is the substitution of a hydroxy group in the 2-position with an amino group effected by a Smiles rearrangement reaction of the 2-methylpropanamide derivative 6. The affinity of the new compounds for the dopamine D-2 receptor in the anterior pituitary gland was evaluated. 2-Fluoroapomorphine was the most potent compound, being 1.5 times more potent than (-)-apomorphine. The structure-activity relationships are discussed in relation to a previously proposed receptor model.