反应详情

To a solution of 2.84 g (8.41 mmol) [3-(2,2-difluoro-2-pyridin-2-yl-ethylamino)-2oxo-2H-pyrazin-1-yl]-acetic acid ethyl ester (preparation described in example 17, step K) in 10.0 mL methanol was added 8.83 mL (8.83 mmol) 1.0N lithium hydroxide (aq) and the light yellow solution stirred 1 h at room temperature. The reaction pH was adjusted to 7.0 with a dropwise addition of 1.0N HCl in ether to give a precipitate. The solid was removed by filtration, washed well with water and dried under high vacuum for 24 h to give 3-[2,2-Difluoro-2-pyridin-2-yl-ethylamino)-2-oxo-2H-pyrazin-1-yl]acetic acid as a white solid: 1H NMR (DMSO-d6, 400 MHz): δ 13.13 (br s, 1H), 8.70 (d, 1H, J=4.7 Hz), 7.98 (t, 1H, J=7.8 Hz), 7.70 (d, 1H, J=7.9 Hz), 7.60–7.55 (m, 1H), 7.16 (t, 1H, J=6.7 Hz), 6.84 (d, 1H, J=4.7 Hz), 6.73 (d, 1H, J=4.6 Hz), 4.57 (s, 2H), 4.24 (dt, 2H, J=6.6 and 15.2 Hz); MS (Electrospray): M+H=311.0.

1. customto give a precipitate
2. customThe solid was removed by filtration
3. washwashed well with water
4. customdried under high vacuum for 24 h
5. customto give 3-[2,2-Difluoro-2-pyridin-2-yl-ethylamino)-2-oxo-2H-pyrazin-1-yl]acetic acid as a white solid