A series of spirocyclic piperidine derivatives were designed and synthesized as σ1 receptor ligands. In vitro competition binding assays showed that 1′-(4-(2-fluoroethoxy) benzyl)-3 H- spiro [2-benzofuran-1, 4′-piperidine](19) possessed high σ1 receptor affinity (K i= 0.79 nM)
![3-Methyl-3H-spiro[isobenzofuran-1,4'-piperidine] hydrochloride Structure](https://image.chemsrc.com/caspic/028/747353-15-7.png)
![1'-benzyl-3-methoxy-3H-spiro[isobenzofuran-1,4'-piperidine] Structure](https://image.chemsrc.com/caspic/387/398476-50-1.png)
![1'-benzyl-3H-spiro[isobenzofuran-1,4'-piperidine]-3-carbonitrile Structure](https://image.chemsrc.com/caspic/210/477352-23-1.png)