Synthesis and dopamine receptor pharmacological evaluations on ring C ortho halogenated 1-phenylbenzazepines

A series of 1-phenylbenzazepines containing bromine or chlorine substituents at the ortho position of the appended phenyl ring (2'-monosubstituted or 2',6'- disubstituted patterns) were synthesized and evaluated for affinity towards dopamine D1R, D2R and D5R. As is typical of the 1-phenylbenzazepine scaffold, the compounds displayed selectivity towards D1R and D5R; analogs generally lacked affinity for D2R. Interestingly, 2',6'-dichloro substituted analogs showed modest D5R versus D1R selectivity whereas this selectivity was reversed in compounds with a 2'-halo substitution pattern. Compound 10a was identified as a D1R antagonist (K-1 = 14 nM; IC50 = 9.4 nM).