Synthesis, nicotinic acetylcholine receptor binding, and antinociceptive properties of 2-exo-2-(2'-substituted 5'-pyridinyl)-7-azabicyclo[2.2.1]heptanes. Epibatidine analogues.
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Carroll FI, Liang F, Navarro HA, Brieaddy LE, Abraham P, Damaj MI, Martin BR
Synthesis, nicotinic acetylcholine receptor binding, and antinociceptive properties of 2-exo-2-(2'-substituted 5'-pyridinyl)-7-azabicyclo[2.2.1]heptanes. Epibatidine analogues.
J Med Chem. 2001 Jun 21;44(13):2229-37.
- PubMed ID
- 11405659 [ View in PubMed]
- Abstract
A convenient, high-yield synthesis of 7-tert-butoxycarbonyl-7-azabicyclo[2.2.1]hept-2-ene (5), which involved the addition of tributyltin hydride to 7-tert-butoxycarbonyl-2-p-toluenesulfonyl-7-azabicyclo[2.2.1]hept-2-ene (4) followed by elimination of the tributyltin and p-tolylsulfonyl groups using tetrabutylammonium fluoride was developed. The addition of 2-amino-5-iodopyridine to 5 under reductive Heck conditions provided 7-tert-butoxycarbonyl-2-exo-(2'-amino-5'-pyridinyl)-7-azabicyclo[2.2.1]heptane (6). Compound 6 was the key intermediate used to prepare epibatidine analogues where the 2'-chloro group on the pyridine ring was replaced with a fluorine (1b), bromine (1c), iodine (1d), hydroxy (1e), amino (1f), dimethylamino (1g), trifluoromethanesulfonate (1h), and hydrogen (1i) group. (+)- and (-)-Epibatidine and compounds 1b-d and 1i all possess similar binding affinities at the alpha(4)beta(2) nAChR receptors labeled by [(3)H]epibatidine. Compound 1f has affinity similar to nicotine, whereas compounds 1e, 1g, and 1h have much lower affinity. The binding affinity appears to be dependent upon the electronic nature of the substituent. However, other factors are also involved. None of the compounds possesses appreciable affinity for the alpha(7) nAChR labeled by [(125)I]iodo-MLA. With the exception of 1f and 1g, all the epibatidine analogues are full agonists (tail flick test) in producing antinociception after intrathecal injection in mice.
DrugBank Data that Cites this Article
- Binding Properties
Drug Target Property Measurement pH Temperature (°C) Epibatidine Neuronal acetylcholine receptor subunit beta-2 Ki (nM) 0.058 N/A N/A Details Epibatidine Neuronal acetylcholine receptor subunit beta-2 Ki (nM) 0.018 N/A N/A Details Nicotine Neuronal acetylcholine receptor subunit beta-2 Ki (nM) 1.26 N/A N/A Details Nicotine Neuronal acetylcholine receptor subunit beta-2 Ki (nM) 1.5 N/A N/A Details Nicotine Neuronal acetylcholine receptor subunit beta-2 Ki (nM) 1.01 N/A N/A Details