Synthesis of Analogues of (−)-Cytisine for in Vivo Studies of Nicotinic Receptors Using Positron Emission Tomography
摘要:
9-Substituted analogues of (-)-cytisine were synthesized in high yields via palladium-mediated couplings of either 9- (-)-bromocytisine and organostannanes or 9-(-) trimethylstannylcytisine and fluorobromobenzene. The protection of the amine with a nitroso group and the use of PdCl2(PPh3)(2) to carry out the Stille reaction allowed the rapid synthesis of 9-(4'-[F-18]fluorophenyl)cytisine (F-18: t(1/2) = 109.7 min), a new promising radioligand (radiochemical yield: 10% from [F-18]KF, 150 min, four steps) for positron emission tomography studies of alpha(4)beta(2) nicotinic receptors.
An efficient and environmentally electrooxidative N-nitrosation of secondary amines using potassium/sodium nitrite as nitrosating agents has been developed. This strategy break through the innate combination of sodium nitrite and a strong acid. The reaction is compatible with the late-stage modification of pharmaceutical compounds and could be conducted in gram scale with high reaction efficiency.
9-Substituted analogues of (-)-cytisine were synthesized in high yields via palladium-mediated couplings of either 9- (-)-bromocytisine and organostannanes or 9-(-) trimethylstannylcytisine and fluorobromobenzene. The protection of the amine with a nitroso group and the use of PdCl2(PPh3)(2) to carry out the Stille reaction allowed the rapid synthesis of 9-(4'-[F-18]fluorophenyl)cytisine (F-18: t(1/2) = 109.7 min), a new promising radioligand (radiochemical yield: 10% from [F-18]KF, 150 min, four steps) for positron emission tomography studies of alpha(4)beta(2) nicotinic receptors.
THE OXIDATION OF HYDROXYLAMINE BY FREMY’S SALT. PREPARATION OF<i>N</i>-NITROSAMINES AND TETRAZENES
作者:M. P. Vazaquez Tato、Luis Castedo、Ricardo Riguera
DOI:10.1246/cl.1985.623
日期:1985.5.5
Treatment of secondary amines with Fremy’s salt in aqueous sodium carbonate solution and in the presence of hydroxylamine gives a high yield of either N-nitrosamines or sym-tetrazenes. A mechanism for these conversions is proposed.