P(Cl)(Cl)(Cl)=O.CN(C)[C:8](=[O:11])[CH2:9][CH3:10].[Cl:13][C:14]1[CH:19]=[CH:18][C:17]([C:20]2[N:21]([CH2:26][CH3:27])[CH:22]=[CH:23][C:24]=2[CH3:25])=[CH:16][CH:15]=1.O.O.O.C([O-])(=O)C.[Na+]>ClCCCl.O>[Cl:13][C:14]1[CH:15]=[CH:16][C:17]([C:20]2[N:21]([CH2:26][CH3:27])[C:22]([C:8](=[O:11])[CH2:9][CH3:10])=[CH:23][C:24]=2[CH3:25])=[CH:18][CH:19]=1Phosphorus oxychloride (0.47 g, 0.28 ml, 3.00 mmol) was added dropwise to previously cooled (0 to 5° C.) N,N-dimethyl propionamide (0.30 g, 0.27 ml, 3.00 mmol) maintaining the temperature between about 0° C. to about 5° C. The resulting reaction mixture was then allowed to warm to room temperature (about 25° C.), which was then stirred at room temperature (about 25° C.) for 20 minutes. The reaction mixture was then diluted with 1,2-dichloroethane (15 ml), the resulting mixture was cooled to 0° C., to it was then added 2-(4-chlorophenyl)-1-ethyl-3-methyl-1H-pyrrole (compound 51a, 0.6 g, 2.73 mmol) in 1,2-dichloroethane (15 ml) dropwise. The reaction mixture so formed was heated to reflux for 30 minutes. The progress of the reaction was monitored by TLC. The reaction mixture was then allowed to cool to room temperature, and to it was then added a solution of sodium acetate trihydrate (1.23 g, 15.0 mmol) in 14 ml water. The reaction mixture so obtained was heated to reflux for 30 minutes. Two phases formed in the reaction mixture were then separated. The aqueous layer was extracted with dichloromethane (3×30 ml). The combined organic layer was washed with water (1×30 ml) and dried over anhydrous Na2SO4. The solvent was evaporated from the dried organic layer under reduced pressure to obtain a crude product, which was then purified by flash column chromatography using 10% ethyl acetate in hexanes as an eluent to obtain the title compound (0.5 g, 66.4%).
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