1,3-dimethyl-5-oxo-N-phenyl-4H-pyrazole-4-carboxamide

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1,3-Dimethylpyrazole-5-one above (11.2 g) and triethylamine (10.2 g) were dissolved in dry benzene and phenyl isocyanate (12 g) added. The mixture was stirred 16-18 hrs at room temperature, whereupon it was extracted with water (4 × 50 ml). The combined aqueous extracts were acidified with dilute hydrochloric acid and the mixture refrigerated for several hours. The product was then recovered by filtration and dried. 4,5-dihydro-1,3-dimethyl-5-oxo-N-phenyl-4-pyrazolecarboxamide (17.5 g, 76%) was obtained as a colourless powder, m.p. 231-233° C. was extracted with water (4 × 50 ml) the mixture refrigerated for several hours The product was then recovered by filtration dried