C([C:4]1[C:8]([CH3:9])=[C:7]([C:10]([C:12]2[CH:17]=[CH:16][C:15]([CH3:18])=[CH:14][CH:13]=2)=[O:11])[N:6]([CH3:19])[C:5]=1[CH2:20][C:21]([O:23][CH2:24][CH3:25])=[O:22])(O)=O.N1C2C(=CC=CC=2)C=CC=1>[Cr]([O-])([O-])=O.[Cu+2]>[CH3:19][N:6]1[C:7]([C:10]([C:12]2[CH:17]=[CH:16][C:15]([CH3:18])=[CH:14][CH:13]=2)=[O:11])=[C:8]([CH3:9])[CH:4]=[C:5]1[CH2:20][C:21]([O:23][CH2:24][CH3:25])=[O:22]A solution of 33.0 g. (0.096 mole) of ethyl 3-carboxy-1,4-dimethyl-5-(p-toluoyl)-pyrrole-2-acetate in 200 ml. of quinoline with 0.1 g. copper chromite added is heated under nitrogen for 6 hours at 200° C., then for 30 minutes at 220° C. The quinoline is distilled off in vacuo. The residue is dissolved in ether and washed successively with dilute hydrochloric acid, dilute sodium hydroxide, and brine; dried over magnesium sulfate; and the solvent evaporated in vacuo to give a brown oily residue which crystallizes. It is recrystallized from methanol, sublimed at 150° C. (0.025 mm/Hg) and recrystallized from hexane to give ethyl 1,4-dimethyl-5-(p-toluoyl)-pyrrole-2-acetate as a white solid, m.p. 90-93° C.
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