3-(Dimethylamino)-1-phenyl-2-propen-1-one → 7-Phenylpyrazolo[1,5-a]pyrimidine

Beteiligte Stoffe

Reaktionsschritte

A reaction mixture of 5.25 g. of 3-dimethylaminoacrylophenone [von H. Meerwein et al., Annalen der Chemie, Band 641, 1-39, (1961)] and 2.50 g. of 3-aminopyrazole in 25 ml. of glacial acetic acid is refluxed for 3.5 hours, cooled overnight and evaporated to a thick yellow oil. This oil is dissolved in methylene chloride, washed with a saturated aqueous solution of sodium bicarbonate, dried over sodium sulfate and then passed through a sintered glass funnel or a chromatographic column packed in vacuo with hydrous magnesium silicate. Additional methylene chloride is passed through the funnel (column). The effluent is refluxed on a steam bath. The gradual addition of hexane produces crystals. The crystallization from methylene chloride with hexane is repeated giving the desired product, m.p. 72°-73° C.

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