反应详情

To a solution of tert-butyl (3R)-3-({5-[(1E)-3-ethoxy-3-oxo-1-propen-1-yl]-2-pyrazinyl}amino)-1-piperidinecarboxylate (6.26 g) in a mixture of 1,4-dioxane (25 mL) and MeOH (5 mL) was added 4N hydrogen chloride solution in ethyl acetate (30 mL) in water bath. The mixture was stirred at same temperature for 3 hrs. After evaporation of solvent, the residue was triturated with isopropylether to give ethyl (2E)-3-{5-[(3R)-3-piperidinylamino]-2-pyrazinyl}acrylate dihydrochloride (5.8 g) as an amorphous powder. 1H-NMR (300 MHz, DMSO-d6) δ 1.25 (3H, t, J=7 Hz), 1.46-1.65 (1H, m), 1.65-1.85 (1H, m), 1.85-2.06 (3H, m), 2.66-3.00 (2H, m), 3.05-3.25 (1H, m), 3.25-3.41 (1H, m), 4.18 (2H, q, J=7 Hz), 6.54 (1H, d, J=15 Hz), 7.57 (1H, d, J=15 Hz), 7.95-8.19 (2H, m), 8.28 (1H, s), 9.14 (2H, br peak)

1. customAfter evaporation of solvent
2. customthe residue was triturated with isopropylether