反应详情

Part B: To a stirred suspension of 2,4-dichloroaniline (19.44 gram, 0.12 mol) in concentrated HCl (25 mL) and acetic acid (75 mL) at 0° C. is added a solution of NaNO2 (9.0 gram, 0.13 mol) in water (50 mL) and the resulting solution is stirred for 15 minutes. A solution of dimethyl 2-(4-chlorobenzoylamino)malonate (28.55 gram, 0.10 mol) in acetone (200 mL) is slowly added while keeping the temperature below 0° C. A solution of K2CO3 (120 gram) in water (200 mL) is slowly added and the resulting black mixture is stirred for 30 minutes at 0° C. The mixture is extracted three times with EtOAc. The collected organics are washed with water, aqueous NaHCO3 and water, respectively, dried over MgSO4, filtered and concentrated in vacuo. The residue is dissolved in methanol (500 mL) and a solution of sodium (1 gram) in methanol (75 mL) is added. The resulting stirred mixture is allowed to stand overnight at room temperature and cooled in a refrigerator. The formed precipitate is collected by filtration and washed with methanol to give methyl 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-1H-1,2,4-triazole-3-carboxylate (11.4 gram, 30% yield). Melting point: 153-154° C. 1H-NMR (200 MHz, CDCl3): δ 4.07 (s, 3H), 7.28-7.60 (m, 7H).

1. customthe temperature below 0° C
2. stirringthe resulting black mixture is stirred for 30 minutes at 0° C
3. extractionThe mixture is extracted three times with EtOAc
4. washThe collected organics are washed with water, aqueous NaHCO3 and water
5. dry with materialrespectively, dried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. dissolutionThe residue is dissolved in methanol (500 mL)
9. additiona solution of sodium (1 gram) in methanol (75 mL) is added
10. stirringThe resulting stirred mixture
11. waitto stand overnight at room temperature
12. temperaturecooled in a refrigerator
13. filtrationThe formed precipitate is collected by filtration
14. washwashed with methanol