[NH:1]([C:3]1[N:8]=[CH:7][CH:6]=[CH:5][N:4]=1)[NH2:2].[F:9][C:10]([F:20])([F:19])[C:11](=O)[CH2:12][C:13](OCC)=[O:14]>C(O)(=O)C>[N:4]1[CH:5]=[CH:6][CH:7]=[N:8][C:3]=1[N:1]1[C:13]([OH:14])=[CH:12][C:11]([C:10]([F:20])([F:19])[F:9])=[N:2]1A mixture of 2 g (9 mmol) of 2-hydrazinopyrimidine and ethyl trifluoroacetoacetate (2.6 ml; 9.1 mmol) in 10 ml of acetic acid was refluxed for 60 hours with stirring under nitrogen and then cooled. The mixture was concentrated in vacuo, the residue was diluted with 100 ml of water, and the mixture was extracted with ethyl acetate (3×). The combined organic layer was dried over magnesium sulfate, and concentrated in vacuo. The resulting residue was dried in vacuo to afford 700 mg of 1-(2-pyrimidinyl)-3-trifluoromethyl-5-hydroxypyrazole as a red gum.
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