Reaktion #45742

Reaktionsgleichung

trimethylsilyldiazomethane diethyl ether

sodium dihydrogenphosphate dihydrate

2-methyl-2-butene

sodium chlorite

sodium hydrogencarbonate

hydrochloric acid

2-Cyclopropyl-7-fluoro-6-formyl-5-methyl-1,3-benzoxazole-4-carbonitrile

→

Methyl 4-cyano-2-cyclopropyl-7-fluoro-5-methyl-1,3-benzoxazole-6-carboxylate

Lösungsmittel

water

tetrahydrofuran

ethyl acetate

tert-butanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe solvent was evaporated away under reduced pressure
2. 2
   ExtraktionThe aqueous layer was further extracted twice with ethyl acetate
3. 3
   Waschenwashed with saturated brine
4. 4
   Trocknendried over anhydrous sodium sulfate
5. 5
   SonstigeThe insoluble matter was separated by filtration
6. 6
   Sonstigethe solvent was evaporated away under reduced pressure
7. 7
   workup.ADDITIONBenzene (6 ml) and methanol (2 ml) were added to it
8. 8
   workup.STIRRINGAfter stirring at room temperature for 18 hours
9. 9
   ExtraktionThe solution was extracted three times with ethyl acetate
10. 10
    Waschenwashed with saturated brine
11. 11
    Trocknendried over anhydrous sodium sulfate

Vorschrift

2-Cyclopropyl-7-fluoro-6-formyl-5-methyl-1,3-benzoxazole-4-carbonitrile (I-182) (280 mg, 1.15 mmol) was dissolved in tert-butanol (8 ml), tetrahydrofuran (6 ml) and water (6 ml), then at 0° C., sodium dihydrogenphosphate dihydrate (268 mg, 1.72 mmol), 2-methyl-2-butene (515 μl, 4.59 mmol), then sodium chlorite (purity 80%, 389 mg, 3.44 mmol) were added. After stirring at room temperature for 6 hours, the solvent was evaporated away under reduced pressure. The residue was fractionated with ethyl acetate and aqueous 1 mol hydrochloric acid solution. The aqueous layer was further extracted twice with ethyl acetate. The organic layers were combined, washed with saturated brine, and dried over anhydrous sodium sulfate. The insoluble matter was separated by filtration, then the solvent was evaporated away under reduced pressure. Benzene (6 ml) and methanol (2 ml) were added to it, then at 0° C., 2 M trimethylsilyldiazomethane/diethyl ether solution (1.15 ml, 2.29 mmol) was added. After stirring at room temperature for 18 hours, an aqueous saturated sodium hydrogencarbonate solution was added at 0° C. The solution was extracted three times with ethyl acetate. The organic layers were combined, washed with saturated brine, and dried over anhydrous sodium sulfate.

Quelle