To a stirred mixture of 75.0 ml of monochlorobenzene, 7.4 g of 3-(4-dimethylaminophenyl)-6-dimethylaminophthalide and 2.2 g of N-methylpyrrole maintained at 0°-5° C. by means of an external ice-bath, there was slowly added 6.65 g of anhydrous aluminum chloride. After stirring for approximately three hours, there was slowly added with continued cooling at 0°-5° C., 100 ml of water and 100 ml of ethylene dichloride. The layers were separated and the organic layer extracted with 150 ml of fresh water. The organic layer was then extracted with 100 ml of 3N hydrochloric acid, separated and the pH of this aqueous acid layer adjusted to 4.5 with five percent aqueous sodium hydroxide solution. The green solid which had formed was collected by filtration. After reslurrying in a mixture of acetone and methanol, the solid was filtered and dried to obtain 5.2 g of 2-[α-(4-dimethylaminophenyl)-α-(1-methyl-2-pyrrolyl)]methyl-5-dimethylaminobenzoic acid (Formula III: R=CH3 ; X=H; Y=4-(CH3)2 --NC6H4 ; Z=1-CH3 -2-pyrrolyl).
