Water → 3-(2-Pyrazinyl)-1-azabicyclo[2.2.2]oct-2-ene

Participants

Reaction Steps

Thionyl chloride (0.24 g. 1.55 mmol) was added dropwise to a rapidly stirred solution of 3-(2-pyrazinyl)-1-azabicyclo[2.2.2]octan-3-ol (0.21 g, 1.02 mmol) in dichloromethane (10 ml) at -5° C. The reaction mixture was warmed to room temperature and then refluxed for 3 h. Water (5 ml) was added to the solution, basified to pH >10 with potassium carbonate and extracted with dichloromethane (3×50 ml). The combined extracts were dried (Na2SO4), the solvent removed under vacuum and the residue chromatographed through alumina (Grade II-III) using dichloromethane/methanol (98:2) as eluant to give 3-(2-pyrazinyl)-1-azabicyclo[2.2.2]oct-2-ene as a pale yellow solid (0.14 g), δ (360 MHz, CDCl3) 1.54-1.61 (2H, m, CH2); 1.77-1.95 (2H, m, CH2); 2.63-2.71 (2H, m, CH2 --N); 3.02-3.09 (2H, m, CH2 --N); 3.53-3.56 (1H, m, CH-bridgehead); 7.30 (1H, d, J=1.5 Hz vinyl-H); 8.41 (1H, d, J=2 Hz, pyrazine-H); 8.52 (1H, dd, J=1 and 2 Hz, pyrazine-H) 8.78 (1H, d, J=1 Hz, pyrazine-H).

Provenance & Evidence