Reaktion #44295

Reaktionsgleichung

2-(2-bromoethoxy)tetrahydro-2H pyran

4-iodopyrazole

Cs2CO3

DMF

→

4-iodo-1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-1H-pyrazole

Ausbeute 87.1%

Lösungsmittel

water

EtOAc

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGthe reaction was stirred at 70° C. for 16 hours
2. 2
   TemperaturAfter cooling down
3. 3
   SonstigeThe organic layer was collected
4. 4
   Extraktionthe aqueous layer was extracted with EtOAc (3×100 mL)
5. 5
   WaschenThe combined organic layers were washed with water (3×100 mL)
6. 6
   Trocknendried over Na2SO4
7. 7
   Einengenconcentrated
8. 8
   Sonstigeto afford dark brown oil
9. 9
   SonstigeThe crude product was purified on a silica gel column
10. 10
    Wascheneluting with ethyl acetate and hexanes

Vorschrift

In a round bottom flask was added 4-iodopyrazole (10.22 g, 52.70 mmol), Cs2CO3 (20.6 g, 63.2 mmol), and anhydrous DMF (100 mL). The suspension was stirred at 23° C. for 5 min. 2-(2-bromoethoxy)tetrahydro-2H pyran (9.95 mL, 63.2 mmol) was added and the reaction was stirred at 70° C. for 16 hours. After cooling down, EtOAc (100 mL) and water (100 mL) was added to the reaction. The organic layer was collected, and the aqueous layer was extracted with EtOAc (3×100 mL). The combined organic layers were washed with water (3×100 mL), dried over Na2SO4, and concentrated to afford dark brown oil. The crude product was purified on a silica gel column eluting with ethyl acetate and hexanes to provide 4-iodo-1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-1H-pyrazole as yellow oil (14.78 g, 87% yield). 1H NMR (300 MHz, DMSO-d6) δ 7.89 (s, 1H) 7.52 (s, 1H) 4.47-4.56 (m, 1H) 4.25-4.35 (m, 2H) 3.81-3.96 (m, 1H) 3.66-3.75 (m, 1H) 3.45-3.57 (m, J=2.83 Hz, 1H) 3.32-3.40 (m, 1H) 1.34-1.71 (m, 6H).

Quelle