[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[NH:12][N:11]=[CH:10][C:9]=2[CH:13]=O)=[CH:4][CH:3]=1.C(O)(=O)[CH2:16][C:17]([OH:19])=[O:18].N1CCCCC1.Cl>O.COCCOCCOC>[F:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]2[NH:12][N:11]=[CH:10][C:9]=2/[CH:13]=[CH:16]/[C:17]([OH:19])=[O:18])=[CH:6][CH:7]=1
A mixture of 5-(4-fluorophenyl)-1H-pyrazole-4-carbaldehyde (1.0 g), malonic acid (0.67 g), piperidine (0.54 g) and bis(2-methoxyethyl) ether (10 mL) was stirred at 110° C. for 6 hrs. Water and 1N hydrochloric acid were added to acidify the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated. The obtained residue was subjected to silica gel column chromatography to give (2E)-3-[5-(4-fluorophenyl)-1H-pyrazol-4-yl]acrylic acid as colorless crystals (0.12 g, yield 10%) from a fraction eluted with hexane-ethyl acetate (1:9, v/v). Recrystallization thereof from acetone-diisopropyl ether gave colorless prism crystals. melting point: 276-277° C.
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