Synthesis and in vitro biological profile of all four isomers of the potent muscarinic agonist 3-(3-methyl-1,2,4-oxadiazol-5-yl)-1-azabicyclo[2.2.1]heptane
作者:Graham A. Showell、Raymond Baker、Juliet Davis、Richard Hargreaves、Stephen B. Freedman、Karst Hoogsteen、Shailendra Patel、Roger J. Snow
DOI:10.1021/jm00083a016
日期:1992.3
The four stereoisomers of the muscarinic agonist 7 have been synthesized from enantiomerically pure exo-azanorbornane esters (13a,b). The esters were obtained in optically active form by separation of the carboxamide diastereomers 12a,b, formed from the borane complex of exo-azanorbornane-3-carboxylate 10 and a chiral amine auxiliary. Using the known chirality of (R)-alpha-methylbenzylamine, an X-ray
毒蕈碱激动剂7的四种立体异构体是从对映体纯的外氮-天山硼烷酯(13a,b)合成的。通过分离由外-叠氮基硼烷-3-羧酸酯10的硼烷配合物和手性胺助剂形成的羧酰胺非对映异构体12a,b,以旋光形式得到酯。使用(R)-α-甲基苄基胺的已知手性,对12a进行X射线分析,以确定金刚烷烷C4手性中心的绝对构型。手性酯13a,b中的每一种都在氮杂硼烷烷环的C3处伴随差向异构化而分别转化为恶二唑,以提供异构体的热力学平衡混合物。色谱分离,然后通过NMR和GC分析各异构体,从而证实了7的所有四种异构体的绝对立体化学。在生化和药理学分析中进行的全面生物学评估表明,3R,4R异构体在受体结合研究中最活跃,在药理制剂中最有效,与M1相比,在M2和M3位点的效价提高了50倍。