反应详情

A solution of 6-chloro-2-methoxy-3-nitro-pyridin-4-ylamine (8.90 g, 43.7 mmol, prepared as described in the previous step) in 1,4-dioxane (200 mL) and water (100 mL) was treated with Cs2CO3 (35.6 g, 109 mmol) and 2-chlorophenylboronic acid (10.2 g, 65.5 mmol) under Ar. To the resulting mixture was added Cl2Pd(dppf).DCM (3.50 g, 4.30 mmol) and the mixture was then heated to 90° C. for 15 h. The cooled mixture was diluted with EtOAc (500 mL) and washed with water (500 mL). The aqueous layer was extracted twice with EtOAc (3×300 mL). The combined extracts were dried over MgSO4 and concentrated in vacuo. The residue was purified on silica (0:100-50:50 EtOAc/hexanes) to yield a yellowish white solid. The solid was dissolved in EtOAc (200 mL) with heating and hexane (150 mL) was added. The resulting solution was concentrated until the solution became turbid and heated to yield a clear solution which was left overnight at room temperature. The crystals formed were collected by suction filtration. This recrystallization procedure was repeated twice to yield 6-(2-chloro-phenyl)-2-methoxy-3-nitro-pyridin-4-ylamine. 1H-NMR (400 MHz, CDCl3) δ: 7.59-7.66 (m, 1H), 7.43-7.51 (m, 1H), 7.31-7.39 (m, 2H), 6.69 (s, 1H), 6.11 (br. s., 2H), 4.07 (s, 3H). Mass Spectrum (LCMS, ESI pos.) Calculated for C12H10N3O3Cl: 280.0 (M+H), Measured: 280.1.

1. washwashed with water (500 mL)
2. extractionThe aqueous layer was extracted twice with EtOAc (3×300 mL)
3. dry with materialThe combined extracts were dried over MgSO4
4. concentrationconcentrated in vacuo
5. customThe residue was purified on silica (0:100-50:50 EtOAc/hexanes)
6. customto yield a yellowish white solid
7. temperaturewith heating
8. concentrationThe resulting solution was concentrated until the solution
9. temperatureheated
10. customto yield a clear solution which
11. customThe crystals formed
12. filtrationwere collected by suction filtration
13. customThis recrystallization procedure