Reaktion #75898

Reaktionsgleichung

(1-ethyl-5-hydroxy-3-methyl-1H-pyrazol-4-yl)-phenyl-methanone

phosphorus oxychloride

sodium hydrogen carbonate

→

(5-chloro-1-ethyl-3-methyl-1H-pyrazol-4-yl)-phenyl-methanone

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted three times with 70 ml of dichloromethane
2. 2
   TrocknenThe combined extracts were dried over magnesium sulphate
3. 3
   Filtrationfiltered
4. 4
   Sonstigeevaporated
5. 5
   SonstigeThe residue was purified by flash chromatography on silica gel
6. 6
   Waschenfor the elution

Vorschrift

A solution of 2.6 g of (1-ethyl-5-hydroxy-3-methyl-1H-pyrazol-4-yl)-phenyl-methanone in 4 ml of phosphorus oxychloride was stirred at 80° C. for 1.5 h. The mixture was poured into 300 ml of saturated sodium hydrogen carbonate and extracted three times with 70 ml of dichloromethane. The combined extracts were dried over magnesium sulphate, filtered and evaporated. The residue was purified by flash chromatography on silica gel using ethyl acetate/petroleum ether (bp 40-60° C.) (1:4) for the elution to give 1.74 g of (5-chloro-1-ethyl-3-methyl-1H-pyrazol-4-yl)-phenyl-methanone as a pale yellow liquid. Mass spectrum (ES) m/z 249 [M+H]+, 290 [M+H+CH3CN]+.

Quelle