Fluorinated 2-Arylcyclopropan-1-amines - A new class of sigma receptor ligands.

Stereoisomeric 2-aryl-2-fluoro-cyclopropan-1-amines have been discovered as a new class of σ receptor ligands showing different selectivity for the two subtypes of the receptor. Generally, compounds substituted in 4-position are much more active than corresponding 3-substituted isomers. trans-2-Fluoro-2-(4-methoxyphenyl)cyclopropan-1-amine (19a) was the most potent (Ki = 4.8 nM) σ1 receptor ligand, while cis-2-fluoro-2-(4-trifluoromethylphenyl)cyclopropan-1-amine (20b) was the most potent (Ki = 95 nM) σ2 receptor ligand.