反应详情

Equip a 3-L reaction flask with a cooling bath, air stirrer, and thermometer probe and charge with 4-chloro-N-dimethylaminomethylene-2-thiophene carboxamide. (155 g, 0.715 moles) and HOAc (1500 mL) to form a solution. Using an ice-water cooling bath to maintain the temperature at ≦30° C., add methylhydrazine (33.2 g, 0.721 moles) dropwise using an addition funnel over 15-20 min to form a light yellow slurry. Heat the reaction gradually to 90° C. and hold at 90° C. for 30 min. Analyze the mixture by GC, then cool the reaction to about 70° C., and concentrate to a thick oil/slurry. Add water (1.67 L) slowly to precipitate solids, cool the mixture to <30° C., filter, and wash with water (1.67 L). Dissolve the wet solids (125.8 g) in warm t-butyl methyl ether (1.64 L), dry over Na2SO4, filter, and concentrate to dryness to provide the title compound as a pale yellow solid (85.8 g, 60%).

1. customEquip
2. temperatureto maintain the temperature at ≦30° C.
3. customover 15-20 min
4. customto form a light yellow slurry
5. temperatureHeat
6. customthe reaction gradually to 90° C.
7. temperatureAnalyze the mixture by GC, then cool
8. customthe reaction to about 70° C.
9. concentrationconcentrate to a thick oil/slurry
10. customAdd water (1.67 L) slowly to precipitate solids
11. temperaturecool the mixture to <30° C.
12. filtrationfilter
13. washwash with water (1.67 L)
14. dissolutionDissolve the wet solids (125.8 g) in warm t-butyl methyl ether (1.64 L)
15. dry with materialdry over Na2SO4
16. filtrationfilter
17. concentrationconcentrate to dryness