Synthesis of N-substituted 9-azabicyclo[3.3.1]nonan-3alpha-yl carbamate analogs as sigma2 receptor ligands

A series of N-substituted 9-azabicyclo3.3.1]nonan-3alpha-yl phenylcarbamate analogs was prepared and their affinities for sigma (sigma(1) and sigma(2)) receptors were measured in vitro. The results of their structure-activity relationship study identified two new compounds, N-(9-(4-aminobutyl)-9-azabicyclo3.3.1]nonan-3alpha-yl)-N'-(2-methoxy-5-methylphenyl)carbamate and N-(9-(6-aminohexyl)-9-azabicyclo3.3.1]nonan-3alpha-yl)-N'-(2-methoxy-5-methylphenyl)carbamate, having a high affinity and selectivity for sigma(2) versus sigma(1) receptors. These compounds were also used in the preparation of biotinylated and fluorescent probes of the sigma(2) receptor.