Reaktion #45768

Reaktionsgleichung

Ethyl 3-bromopyruvate

4-cyano-7-fluoro-5-methyl-6-phenyl-1,3-benzoxazole-2-carbothioamide

sodium hydrogencarbonate

p-toluenesulfonic acid monohydrate

→

compound

Ausbeute 91.3%

Ethyl 2-(4-cyano-7-fluoro-5-methyl-6-phenyl-1,3-benzoxazol-2-yl)-1,3-thiazole-4-carboxylate

Ausbeute 91.3%

Lösungsmittel

toluene

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturby heating
2. 2
   TemperaturAfter cooling to room temperature
3. 3
   Temperaturby heating
4. 4
   Temperaturunder reflux in an oil bath at 125° C. for 15 hours
5. 5
   TemperaturAfter cooling to room temperature
6. 6
   Extraktionfollowed by extraction with ethyl acetate (50 ml×2)
7. 7
   WaschenThe organic layer was washed with an aqueous saturated sodium hydrogencarbonate solution (50 ml) and saturated brine (50 ml)
8. 8
   Trocknendried over anhydrous sodium sulfate
9. 9
   EinengenAfter concentration
10. 10
    Sonstigethe resulting residue was purified by silica gel column chromatography (eluent, chloroform:ethyl acetate=100:1→25:1)

Vorschrift

Ethyl 3-bromopyruvate (72.2 μl, 0.518 mmol) was added to a toluene (10 ml) solution of 4-cyano-7-fluoro-5-methyl-6-phenyl-1,3-benzoxazole-2-carbothioamide (I-196-1) (124 mg, 0.398 mmol), followed by heating under reflux in an oil bath at 125° C. for 2 hours. After cooling to room temperature, p-toluenesulfonic acid monohydrate (15.2 mg, 0.080 mmol) was added to the reaction liquid, followed by heating under reflux in an oil bath at 125° C. for 15 hours. After cooling to room temperature, an aqueous saturated sodium hydrogencarbonate solution (50 ml) and water (50 ml) were added, followed by extraction with ethyl acetate (50 ml×2). The organic layer was washed with an aqueous saturated sodium hydrogencarbonate solution (50 ml) and saturated brine (50 ml), and dried over anhydrous sodium sulfate. After concentration, the resulting residue was purified by silica gel column chromatography (eluent, chloroform:ethyl acetate=100:1→25:1) to obtain the entitled compound (148 mg, 91.2%) as a pale yellow solid.

Quelle