Reaktion #364611

Reaktionsgleichung

sodium hydride

(4-chloro-2-nitrophenyl)isocyanate

ethyl-3-amino-4,4,4-trifluorocrotonate

→

3-(4-chloro-2-nitrophenyl)-6-trifluoromethyl-2,4(1H, 3H)-pyrimidinedione

Lösungsmittel

N,N-dimethylformamide

toluene

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONAfter addition
2. 2
   workup.STIRRINGAfter stirring for 20 min
3. 3
   Sonstigethe cold bath was removed
4. 4
   workup.STIRRINGthe resulting mixture was stirred overnight at ambient temperature
5. 5
   SonstigeThe reaction mixture was partitioned between ethyl acetate and 1N-hydrochloric acid
6. 6
   WaschenThe organic phase was washed with brine (×2)
7. 7
   Trocknendried over anhydrous sodium sulfate
8. 8
   SonstigeThe solvent was removed in vacuo
9. 9
   Sonstigethe residue was purified by column chromatography on silica gel
10. 10
    Wascheneluted with ethyl acetate and hexane (1:1)

Vorschrift

To a suspension of sodium hydride (60% dispersion in oil, 2.5 g) in anhydrous N,N-dimethylformamide (100 ml) was added dropwise a solution of ethyl-3-amino-4,4,4-trifluorocrotonate in toluene (50 ml) at 0° C. under nitrogen atmosphere. After addition, the mixture was stirred for 20 min at same temperature, then cooled to −30° C. A solution of (4-chloro-2-nitrophenyl)isocyanate in toluene (50 ml) was added dropwise. After stirring for 20 min, the cold bath was removed and the resulting mixture was stirred overnight at ambient temperature. The reaction mixture was partitioned between ethyl acetate and 1N-hydrochloric acid. The organic phase was washed with brine (×2) and dried over anhydrous sodium sulfate. The solvent was removed in vacuo and the residue was purified by column chromatography on silica gel eluted with ethyl acetate and hexane (1:1) to afford 3-(4-chloro-2-nitrophenyl)-6-trifluoromethyl-2,4(1H, 3H)-pyrimidinedione (10.2 g) as a yellow solid.

Quelle