反应详情

Combine 3-nitroaniline (3.0 g, 21.7 mmol), dichloromethane (100 mL), pyridine (2.11 mL, 26.0 mmol) and 2-chloro-4-fluorobenzoyl chloride (3.07 mL, 23.9 mmol). Stir at room temperature overnight. Filter the white precipitate, rinse with ether (2×10 mL), and dry under vacuum to provide 2-chloro-4-fluoro-N-(3-nitrophenyl)benzamide (4.92 g, 77%). Combine the 2-chloro-4-fluoro-N-(3-nitrophenyl)benzamide (4.92 g, 16.7 mmol) with ethanol (150 mL), SnCl2.2H2O (18.9 g, 83.6 mmol) and concentrated hydrochloric acid (8.24 mL, 83.6 mmol). Stir at reflux under a nitrogen atmosphere for 2 hr. Neutralize with ammonium hydroxide (15 mL). Filter through celite, wash with dichloromethane (2×15 mL), separate the filtrate, extract with dichloromethane (2×80 mL), and dry the combined organic layers over magnesium sulfate. Filter and concentrate to dryness to provide the title intermediate as an off-white solid (3.04 g, 69%): mass spectrum (ion spray): m/z=265.0(M+1); 1H NMR (DMSO-d6): 10.16 (bs, N—H), 7.60 (dd, J=6.2 Hz, 8.6 Hz, 1H), 7.54 (dd, J=2.5 Hz, 9.0 Hz, 1H), 7.30 (td, J=2.5 Hz, 8.5 Hz, 1H), 7.04 (t, J=2.0 Hz, 1H), 6.93 (t, J=8.0 Hz, 1H), 6.74 (bd, J=7.9 Hz, 1H), 6.29 (dd, J=2.2 Hz, 7.9 Hz, 1H), 5.10 (bs, 2H).

1. temperatureat reflux under a nitrogen atmosphere for 2 hr
2. filtrationFilter through celite
3. washwash with dichloromethane (2×15 mL)
4. customseparate the filtrate
5. extractionextract with dichloromethane (2×80 mL)
6. dry with materialdry the combined organic layers over magnesium sulfate
7. filtrationFilter
8. concentrationconcentrate to dryness