(2-Methoxy-5-nitrophenyl)-3-pyrazin-2-yl-urea → 1-(5-Amino-2-methoxyphenyl)-3-pyrazin-2-yl-urea

Participants

Reaction Conditions

Reaction Steps

A solution of (2-methoxy-5-nitrophenyl)-3-pyrazin-2-yl-urea (Compound 159, Example 3) (16.9 g, 55 mmol) in dimethylformamide (DMF, 320 mL) was shaken under H2 in the presence of palladium on carbon (Pd/C) catalyst (1.6 g, 10% Pd) at 80° C. for 12 h. A second portion of catalyst was added (1.6 g) and shaking was continued for an additional 8 h at the same temperature. The solution was filtered through a pad of celite using an additional 200 mL of DMF. The filtrate was concentrated in vacuo and the residue was triturated with methanol (100 mL). The solid was collected, stirred in boiling methanol, and solids present (1.8 g) were filtered off and discarded. The filtrate was cooled at 4° C. overnight. Solids (1.4 g) were removed by filtration and the filtrate was concentrated in vacuo to a tan solid (2.6 g). The crude solid product was triturated with THF (200 mL), collected by filtration, and dried in vacuo to afford the product as a tan solid (1.85 g, 13%). 1H NMR (300 Mhz, d6 DMSO) δ: 10.10 (s, 1H), 9.94 (br s, 1H), 8.89 (s, 1H), 8.32 (s, 1H), 8.22 (s, 1H), 7.58 (s, 1H), 7.75 (d, 1H), 6.21 (d, 1 H), 4.70 (s, 2H), 3.76 (s, 3H). 13C NMR (75 Mhz, d6-DMSO) δ: 151.4, 149.4, 142.6, 140.9, 139.8, 137.2, 135.2, 128.7, 112.8, 107.7, 106.0, 56.8.

Provenance & Evidence