Quinuclidinone O-Alkynyloximes with muscarinic agonist activity
摘要:
A series of quinuclidinone O-alkynyloximes (14-19) were synthesized and evaluated in radioligand displacement assays for binding affinities to M-1-M-3 muscarinic receptors. Radioligand displacement assays were carried out using [H-3] oxotremorine-M and [H-3] pirenzepine on rat cortical tissue and [H-3] N-methylscopolamine on rat heart and submandibulary glands. Two alkynyloximes 15 and 18 had pirenzepine/oxotromorine M ratios which were indicative of muscarinic agonist Ind partial agonist activity, respectively. They were tested for their mnemonic effects in mice using the swimming escape task and found to attenuate scopolamine induced impairment of the task in mice at 2 mg/kg. The results show that the O-alkynyloxime moiety linked to aza-cycles of appropriate size and rigidity (for example quinuclidine and tropane) is a potentially useful muscarinic pharmacophore that can be exploited for the design of muscarinic agonists. (C) 2001 Elsevier Science Ltd. All rights reserved.
Synthesis and Pharmacological Characterization of <i>O</i>-Alkynyloximes of Tropinone and <i>N</i>-Methylpiperidinone as Muscarinic Agonists
作者:Rong Xu、Meng-Kwoon Sim、Mei-Lin Go
DOI:10.1021/jm9708588
日期:1998.8.1
A number of O-alkynyloximes of tropinone and N-methyl-4-piperidinone have been synthesized and evaluated for muscarinic activity. The affinities of these oximes were tested in homogenates of cerebral cortex, heart, and submandibulary glands from rats using [H-3]pirenzepine and [H-3]- N-methylscopolamine as radioligands. The oximes bind to the cortical muscarinic receptors with pK(i) values varying from 3 to 7. Higher binding affinities were observed for the O-alkynyl tropinone oximes than the corresponding piperidinone analogues. Binding to the muscarinic sites in the heart and submandibulary glands was also observed but with lower affinities. Good M-1 subtype selectivity (10-fold or greater) was observed with some oximes (26a, 28a, 32a) at the cortical sites. These oximes also attenuated scopolamine-induced impairment of the water mask task in mice. Functional assays for Ma activity on the rat aorta showed that all oximes possessed M-3 agonist action but M-2 agonist activity was not observed at the endothelium-denuded rabbit aorta. Analysis of the quantitative structure-activity relationship (QSAR) indicated that the Connolly surface area is an important determinant of activity, accounting for 70% of the variation in cortical binding affinity among the oximes.
On the viability of 5-endo-dig cyclisations of O-propargylic hydroxylamine derivatives, leading to 2,5-dihydroisoxazoles (3-isoxazolines)
作者:Oliver F. Foot、David W. Knight、Ai Cheng Lilian Low、YingFa Li
DOI:10.1016/j.tetlet.2006.11.114
日期:2007.1
O-Propargylic hydroxylamines undergo smooth 5-endo-dig cyclisations upon exposure to 3 equiv of molecular iodine to give respectable yields of the corresponding 4-iodo-2,5-dihydroisoxazoles, which should find a number of applications as intermediates for syntheses amongst this useful class of heterocycles.
Quinuclidinone O-Alkynyloximes with muscarinic agonist activity
作者:Brinda Somanadhan、Weng-Keong Loke、Meng-Kwoon Sim、Mei-Lin Go
DOI:10.1016/s0968-0896(01)00267-x
日期:2002.1
A series of quinuclidinone O-alkynyloximes (14-19) were synthesized and evaluated in radioligand displacement assays for binding affinities to M-1-M-3 muscarinic receptors. Radioligand displacement assays were carried out using [H-3] oxotremorine-M and [H-3] pirenzepine on rat cortical tissue and [H-3] N-methylscopolamine on rat heart and submandibulary glands. Two alkynyloximes 15 and 18 had pirenzepine/oxotromorine M ratios which were indicative of muscarinic agonist Ind partial agonist activity, respectively. They were tested for their mnemonic effects in mice using the swimming escape task and found to attenuate scopolamine induced impairment of the task in mice at 2 mg/kg. The results show that the O-alkynyloxime moiety linked to aza-cycles of appropriate size and rigidity (for example quinuclidine and tropane) is a potentially useful muscarinic pharmacophore that can be exploited for the design of muscarinic agonists. (C) 2001 Elsevier Science Ltd. All rights reserved.