Reaktion #55725

Reaktionsgleichung

hydrochloric acid

3-benzoylacrylic acid

hydrazine

potassium hydroxide

→

4,5-Dihydro-3-phenyl-1H-pyrazole-5-carboxylic acid

Lösungsmittel

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturheated
2. 2
   Temperaturat reflux for 2 hours
3. 3
   Sonstigeto precipitate 7.1 g of solid, melting point 180°-182° C
4. 4
   workup.DISSOLUTIONThis material is dissolved in 40 ml of warm dimethylformamide
5. 5
   workup.ADDITIONtreated wit 140 ml of methanol
6. 6
   Sonstigeto crystallize 3.9 g of the title compound, melting point 199°-201° C.

Vorschrift

A mixture of 10.0 g of 3-benzoylacrylic acid, 1.8 g of hydrazine, and 3.7 g of potassium hydroxide in 30 ml. of aqueous ethanol (1:1) is stirred and heated at reflux for 2 hours. The cooled solution is treated with 5 ml of concentrated hydrochloric acid to pH 4.0 to precipitate 7.1 g of solid, melting point 180°-182° C. This material is dissolved in 40 ml of warm dimethylformamide and treated wit 140 ml of methanol to crystallize 3.9 g of the title compound, melting point 199°-201° C.

Quelle