反应详情

Concentrated hydrogen chloride (2.5 mL) was added dropwise to a solution of the product from step (v) (4.33 g) in methanol (43 mL) at RT and stirred for 14 h. The mixture was concentrated and diluted with methanol. The precipitate was collected by filtration, washed with methanol and dried to give 2.87 g of the sub-title compound as a white solid, which was used without further purification; 1H NMR (300 MHz, d6-DMSO) δ=12.59 (2H, brs), 8.05 (2H, s), 6.89 (1H, d), 6.51 (1H, d), 6.36 (1H, dd), 3.97 (2H, t), 3.52 (2H, t), 3.46 (2H, s), 2.13 (3H, s), 1.78-1.86 (2H, m); LC-MS: m/z 320.

1. concentrationThe mixture was concentrated
2. additiondiluted with methanol
3. filtrationThe precipitate was collected by filtration
4. washwashed with methanol
5. customdried