[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[CH:5]=[CH:4][C:3]=1[C:9](=[O:16])[CH2:10][C:11]1[NH:12][CH:13]=[CH:14][N:15]=1.C1COCC1.[OH-].[K+].[C:24]([O:28][CH2:29][CH3:30])(=[O:27])[CH:25]=[CH2:26]>O.C(O)C>[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[CH:5]=[CH:4][C:3]=1[C:9](=[O:16])[CH:10]([C:11]1[NH:15][CH:14]=[CH:13][N:12]=1)[CH2:26][CH2:25][C:24]([O:28][CH2:29][CH3:30])=[O:27]
1-(2,4-dichlorophenyl)-2-imidazolylethan-1-one (0.80 M) was dissolved with heating as necessary in a stirred mixture of THF (250 ml) and abs. ethanol (250 ml). After cooling to room temperature, potassium hydroxide (0.20 M) was added followed by a dropwise addition of ethyl acrylate (45.8 ml) via addition funnel over 10 min. A room temperature water bath was used to cool the exothermic reaction for the first 30 min. After stirring for 14-16 hours, the reaction was neutralized with gla. acetic acid (10 ml) and concentrated under reduced pressure. The residual dark reddish black slurry was dissolved in abs. ethanol (100 ml) and concentrated again under reduced pressure giving ethyl 5-(2,4-dichlorophenyl)-4-imidazolyl-5-oxopentanoate (2) in 108% yield. The crude material is contaminated with potassium salts and is used without further purification.
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