A solution of 28 ml. (0.22 mole) of p-chlorobenzoyl chloride and 29.4 g. (0.22 mole) of aluminum chloride in 160 ml. of 1,2-dichloroethane (DCE) is added to a refluxing solution of 52.7 g. (0.22 mole) of ethyl 3-ethoxycarbonyl-1-methylpyrrole-2-acetate in 160 ml. of DCE. The mixture is heated under reflux for 41/2 hours, after which it is poured into ice-hydrochloric acid. The mixture is extracted with CHCl3 and the extract is washed successively with dimethyl-amino-n-propylamine solution, dilute hydrochloric acid, and brine, and is dried over magnesium sulfate. Evaporation of the solvent in vacuo and chromotographing the resulting residue on silica gel with a benzene to ether gradient yields the desired product in the first compound-bearing fractions. The solvent is evaporated from these combined fractions, and the resulting residue is recrystallized successively from methylcyclohexane and isopropanol to yield ethyl 5-(p-chlorobenzoyl)-3-ethoxy -carbonyl-1-methylpyrrole-2-acetate as a white solid; m.p. 91°-93° C.
