Reaktion #86051

Reaktionsgleichung

4-nitropyrazole

cesium carbonate

(R)-propylene oxide

→

(R)-1-(4-amino-1H-pyrazol-1-yl)propan-2-ol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe reaction mixture was partitioned between ethyl acetate (3 mL) and half-saturated aqueous sodium chloride solution (3 mL)
2. 2
   SonstigeThe organic was separated
3. 3
   Extraktionthe remaining aqueous phase was extracted with ethyl acetate (2×3 mL)
4. 4
   TrocknenThe collected organic was dried over anhydrous sodium sulfate
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated
7. 7
   workup.DISSOLUTIONThe resulting residue was dissolved in methanol (4 mL)
8. 8
   Sonstigefitted with a palladium on carbon catalyst cartridge at 30° C
9. 9
   EinengenThe resulting solution was concentrated in vacuo
10. 10
    Sonstigeto provide product as a pink oil, which
11. 11
    Sonstigewas used without further purification

Vorschrift

To a solution of 4-nitropyrazole (44.7 mg, 0.395 mmol, 1 equiv) in (R)-propylene oxide (1 mL) was added cesium carbonate (78 mg, 0.24 mmol, 0.61 equiv) at 24° C. After 64 h, the reaction mixture was partitioned between ethyl acetate (3 mL) and half-saturated aqueous sodium chloride solution (3 mL). The organic was separated, and the remaining aqueous phase was extracted with ethyl acetate (2×3 mL). The collected organic was dried over anhydrous sodium sulfate, filtered, and concentrated. The resulting residue was dissolved in methanol (4 mL) and circulated through a H-Cube® continuous-flow hydrogenation reactor (ThalesNano) fitted with a palladium on carbon catalyst cartridge at 30° C. The resulting solution was concentrated in vacuo to provide product as a pink oil, which was used without further purification. 1H NMR (500 MHz, CDCl3), δ: 7.17 (s, 1H), 7.01 (s, 1H), 4.13 (m, 1H), 4.00 (dd, J=13.8, 2.7 Hz, 1H), 3.84 (dd, J=13.8, 7.9 Hz, 1H), 3.47 (s, 1H), 3.15 (br s, 2H), 1.18 (d, J=6.3 Hz, 3H).

Quelle