Reaktion #340488

Reaktionsgleichung

2-(8-fluoro-2,3-dihydro-1,4-benzodioxin-6-yl)-3-oxobutanenitrile

hydrazine dihydrochloride

triethylamine

→

4-(8-fluoro-2,3-dihydro-1,4-benzodioxin-6-yl)-3-methyl-1H-pyrazol-5-amine

Ausbeute 93.0%

Lösungsmittel

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture was refluxed for 2 h
2. 2
   Sonstigethe solvent was evaporated under vacuum
3. 3
   workup.DISSOLUTIONThe residue was dissolved in ethyl acetate (50 ml)
4. 4
   Waschenwashed with saturated sodium bicarbonate (2×25 mL), brine (25 ml)
5. 5
   Trocknenthen dried over sodium sulfate
6. 6
   FiltrationFiltration and concentration

Vorschrift

2-(8-fluoro-2,3-dihydro-1,4-benzodioxin-6-yl)-3-oxobutanenitrile (0.37 g; 1.56 mmol) was dissolved in dry ethanol (5 mL) and hydrazine dihydrochloride (0.20 g, 1.87 mmol) then triethylamine (217 μg, 1.56 mmol) were added. The reaction mixture was refluxed for 2 h, cooled to rt and the solvent was evaporated under vacuum. The residue was dissolved in ethyl acetate (50 ml), washed with saturated sodium bicarbonate (2×25 mL), brine (25 ml) then dried over sodium sulfate. Filtration and concentration gave 4-(8-fluoro-2,3-dihydro-1,4-benzodioxin-6-yl)-3-methyl-1H-pyrazol-5-amine (0.36 g, 93% yield) as an orange solid. 1H NMR (400 MHz, d6-DMSO) δ 6.75 (dd, 1H), 6.65 (m, 1H), 4.30 (m, 4H), 2.14 (s, 3H). MS (EI) for C12H12FN3O2: 250 (MH+).

Quelle