Reaktion #73100

Reaktionsgleichung

HOAc

hydrazine

1-(thiazol-2-yl)ethanone

DMF DMA

→

2-(1H-pyrazol-5-yl)thiazole

Ausbeute 100.0%

Lösungsmittel

DCM

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigewas consumed
2. 2
   EinengenThis material was concentrated under reduced pressure
3. 3
   Sonstigeto give 6.5 g of crude intermediate
4. 4
   TemperaturThe resulting mixture was heated
5. 5
   Temperaturat reflux until all the starting material
6. 6
   Sonstigewas consumed
7. 7
   SonstigeThe layers were separated
8. 8
   Extraktionthe aqueous layer was extracted with DCM (2×50 mL)
9. 9
   TrocknenThe organic layers were dried over MgSO4
10. 10
    Filtrationfiltered
11. 11
    Einengenconcentrated under reduced pressure
12. 12
    SonstigeThe crude material was purified by MPLC (eluted with 0-20% MeOH/DCM)

Vorschrift

Dissolved 1-(thiazol-2-yl)ethanone (1-BA-1, 5 g, 39.7 mmole) in DMF DMA (9.5 g, 2 eq). The resulting mixture was warmed to 100° C. until all the ketone starting material was consumed. This material was concentrated under reduced pressure to give 6.5 g of crude intermediate. This material was dissolved in 25 mL of DCM and 5 mL of HOAc was added, followed by hydrazine (5 g, 4 eq) at 0° C. The resulting mixture was heated at reflux until all the starting material was consumed. The reaction mixture was cooled to rt and neutralized with 30 mL of a saturated NaHCO3 solution. The layers were separated and the aqueous layer was extracted with DCM (2×50 mL). The organic layers were dried over MgSO4, filtered, and concentrated under reduced pressure. The crude material was purified by MPLC (eluted with 0-20% MeOH/DCM) to give 2-(1H-pyrazol-5-yl)thiazole (Compound 2-BA-1, ˜6 g). LC/MS: 152.0 m/z (M+H)+.

Quelle