[CH2:1]([N:3]1[C:7]([OH:8])=[CH:6][C:5]([CH3:9])=[N:4]1)[CH3:2].[OH-].[Ca+2].[OH-].[C:13](Cl)(=[O:20])[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1.Cl>O1CCOCC1.O>[CH2:1]([N:3]1[C:7]([OH:8])=[C:6]([C:13]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)=[O:20])[C:5]([CH3:9])=[N:4]1)[CH3:2]
A suspension of 1.4 g of 2-ethyl-5-methyl-2H-pyrazol-3-ol, 1.6 g of calcium hydroxide and 1.3 ml of benzoyl chloride in 70 ml of 1,4-dioxane was stirred at 110° C. for 3.5 h. 1 ml of water was added and the mixture was stirred at 110° C. for 2 h. 25 ml of 2N hydrochloric acid was added. The mixture was stirred at room temperature for 16 h and extracted three times with 60 ml of ethyl acetate. The combined extracts were dried over magnesium sulphate, filtered and evaporated to give 3.1 g of (1-ethyl-5-hydroxy-3-methyl-1H-pyrazol-4-yl)-phenyl-methanone as a yellow oil which was used without further purification. Mass spectrum (ES) m/z 231 [M+H]+, 272 [M+H+CH3CN]+.
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