反应详情

To a vigorously stirred solution of 6-methyl-5-nitro-N*2*-(4-trifluoromethylbenzyl)-pyrimidine-2,4-diamine (450 mg, 1.376 mmol) in tetrahydrofuran (20 ml) and acetic acid (5 ml) on cold water bath, zinc powder (particle size<10 micron, 5 g) was added by portions in 2 min. Water bath was removed and more zinc powder (2 g) were added. The suspension was stirred at ambient temperature for 60 min and quenched with 10% aqueous sodium carbonate to pH>8. The obtained suspension was extracted with ethyl acetate (10 times). The combined organic solution was filtered via plug of silica gel (10 g) and eluted with 20% in ethyl acetate to give 430 mg of pale yellow oil after evaporation. The product solidified after drying in vacuo. Yield 100%. It was used in the next step without further purification. LC-MS (m/z) 298.1 (MH+); tR=1.68. 1H NMR (500 MHz, DMSO-d6): 2.02 (s, 3H), 3.1-3.8 (br, NH2+H2O), 4.43 (d, 2H), 5.88 (br, 2H), 6.26 (t, 1H, NH), 7.48 (d, 2H), 7.62 (d, 2H).

1. customWater bath was removed
2. additionmore zinc powder (2 g) were added
3. customquenched with 10% aqueous sodium carbonate to pH>8
4. extractionThe obtained suspension was extracted with ethyl acetate (10 times)
5. filtrationThe combined organic solution was filtered via plug of silica gel (10 g)
6. washeluted with 20% in ethyl acetate