A series of N-(benzofuran-2-ylmethyl)-N′-benzylpiperazines bearing alkyl or fluoroalkyl aryl ethers were synthesized and evaluated at various central nervous system receptors. Examination of in vitro σ1 {[3H](+)-pentazocine} and σ2 ([3H] DTG) receptor binding profiles of piperazines 11− 13 and 25− 36 revealed several highly potent and σ1 selective ligands, notably, N-(benzofuran-2-ylmethyl)-N′-(4′-methoxybenzyl) piperazine (13, K i= 2.7 nM, ...
[Costa, Brian de; Radesca, Lilian; Dominguez, Celia; Paolo, Lisa Di; Bowen, Wayne D. Journal of Medicinal Chemistry, 1992 , vol. 35, # 12 p. 2221 - 2230]