As a continuation of our earlier study (J. Med. Chem. 1992, 35, 4334-4343) we conformationally restricted the sigma-receptor ligand 2-(1-pyrrolidinyl)-N-[2-(3,4-dichlorophenyl)ethyl]-N-methylethylamine (1) by incorporating it into a series of homologous piperazines 3-9 and homopiperazines 10 and 11, diazabicyclononanes and decanes, bridgehead bicyclooctanes and nonanes as well as other miscellaneous compounds. sigma-Receptor binding affinities were obtained using [3H](+)-pentazocine in guinea pig brain membrane sigma 1 sites. The studies suggest that the nitrogen lone pair orientation found in the piperazines affords the strongest binding interaction. Other nitrogen lone pair orientations or compounds representing unlikely staggered conformations of 1 [ as in 4-[2-(3,4-dichlorophenyl)ethyl]-1,4-diazabicyclo[3.2.2]nonane (16)] show very weak sigma interaction. Comparison of the binding data of different N-substituted homologues of 1 with those of the 1-[2-(3,4-dichlorophenyl)ethyl]-4-alkylpiperazines suggests that the two nitrogen atoms of 1 are working in opposition to one another in terms of their sensitivity to steric bulk. The high binding affinity of the 1,4-diazabicyclo[4.3.0]nonanes 12 suggests that these may approximate the methyl and pyrrolidine ring conformations found in 1 when it is bound to the sigma receptor. Compound 12 exhibited a 4-fold enantioselectivity favoring (+)-12. The synthesis of 6,7-dichloro-2-[[2-(1-pyrrolidinyl)ethyl]amino]tetralin (19) and its desmethyl derivative 20 permitted constraint of the 3,4-dichlorophenyl and N-methyl moieties of 1 into a gauche orientation. The binding data suggests that this conformation in 1 favors strong binding interaction at sigma-receptors. sigma-Receptor Ki's ranged from 0.55 nM for 1-[2-(3,4-dichlorophenyl)ethyl]-4-n-butylpiperazine (7) to 654 nM for 16. Overall comparison of the results indicate that 1 is subject to considerable conformational freedom and suggests that the sigma receptor is not subject to rigid stereochemical restraints with 1. These results add to our earlier study where we restrained 1 using simple monocyclic heterocycles.

中文翻译：

---

构象受限的N- [2-（3,4-二氯苯基）乙基] -N-甲基-2-（1-吡咯烷基）乙基胺的合成和评价。2.哌嗪，双环胺，桥联双环胺和其他化合物。

作为我们先前研究（J. Med。Chem。1992，35，4334-4343）的继续，我们构象限制了sigma-受体配体2-（1-吡咯烷基）-N- [2-（3,4-二氯苯基）乙基] -N-甲基乙胺（1）掺入一系列同源的哌嗪3-9和均哌嗪10和11中，二氮杂双环壬烷和癸烷，桥头双环辛烷和壬烷以及其他其他化合物。使用[3H]（+）-喷他佐辛在豚鼠脑膜sigma 1位点获得sigma-受体结合亲和力。研究表明，在哌嗪中发现的氮孤对取向提供最强的结合相互作用。其他氮孤对取向或代表1 [不可能的交错构象的化合物，如4- [2-（3,4-二氯苯基）乙基] -1,4-二氮杂双环[3.2]。2] nonane（16）]显示非常弱的sigma相互作用。比较1的不同N-取代同系物与1- [2-（3,4-二氯苯基）乙基] -4-烷基哌嗪的结合数据表明，1的两个氮原子彼此相反。就其对空间体积的敏感性而言。1,4-二氮杂双环[4.3.0]壬烷12的高结合亲和力表明，当它们与sigma受体结合时，它们可能近似于1中发现的甲基和吡咯烷环构象。化合物12表现出有利于（+）-12的4倍对映选择性。6,7-二氯-2-[[[2-（1-吡咯烷基）乙基]氨基]四氢萘林（19）的合成及其去甲基衍生物20允许将1的3,4-二氯苯基和N-甲基部分限制为薄纱的方向。结合数据表明，这种构象在1中有利于σ受体之间的强结合相互作用。σ受体Ki的范围从1- [2-（3,4-二氯苯基）乙基] -4-正丁基哌嗪（7）的0.55 nM到16的654 nM。结果的整体比较表明1受到相当大的影响构象自由，并建议sigma受体不受1的刚性立体化学约束。这些结果增加了我们先前的研究，其中我们使用简单的单环杂环来约束1。