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温度

0 °C

A solution of 1,1-dimethyl-3-(4-((6-nitropyridin-3-yl)oxy)pyridin-2-yl)urea (6.2 g, 20.4 mmol) in MeOH (100 mL) and THF (100 mL) was treated with NH4Cl (332.8 g, 613 mmol) and cooled to 0° C. with stirring. Zinc dust (13.37 g, 204 mmol) was added portion-wise over 10 min and the mixture was stirred overnight as the cooling bath expired. The mixture was diluted with EtOAc and the solids were removed via filtration, and washed with EtOAc. The filtrate was concentrated to dryness, then suspended in EtOAc. The solids were removed by filtration and the filtrate was concentrated to dryness. The resultant brown solid was suspended in MeCN and sonicated for a few minutes. The light brown solid was collected to afford a first crop of 3-(4-((6-aminopyridin-3-yl)oxy)pyridin-2-yl)-1,1-dimethylurea. The MeCN filtrate was concentrated to dryness and again suspended in MeCN. The light brown solid was collected and dried to afford a second crop of 3-(4-((6-aminopyridin-3-yl)oxy)pyridin-2-yl)-1,1-dimethylurea (5.57 g combined, 100%). 1H NMR (400 MHz, DMSO-d6) δ 8.81 (s, 1H), 8.05 (d, J=5.7 Hz, 1H), 7.77 (d, J=2.9 Hz, 1H), 7.33 (d, J=2.4 Hz, 1H), 7.24 (dd, J=8.9, 2.9 Hz, 1H), 6.53-6.49 (m, 2H), 6.00 (br s, 2H), 2.88 (s, 6H); MS (ESI) m/z: 274.1 (M+H+).

1. stirringthe mixture was stirred overnight as the cooling bath
2. customthe solids were removed via filtration
3. washwashed with EtOAc
4. concentrationThe filtrate was concentrated to dryness
5. customThe solids were removed by filtration
6. concentrationthe filtrate was concentrated to dryness
7. customsonicated for a few minutes
8. customThe light brown solid was collected