A solution of 1-[2-(1-methylethoxy)phenyl]piperazine (9.38 g, 0.043 mole) as described in U.S. Pat. Nos. 4,547,505 and 4,438,115, glacial acetic acid (2.57 mL, 0.043 mole), and methanol (27 mL) was cooled in an ice bath and treated with 37% formalin (3.18 mL, 0.043 mole). A solution of 1-(1-methylpyrrol-2-ylmethyl)-2-piperidinone (8.19 g, 0.043 mole) and methanol (27 mL) was added and the resulting solution was stirred overnight at 25° C. under a dry nitrogen atmosphere. Methylene chloride (350 mL) was added followed by 3N sodium hydroxide solution (60 mL). After thorough mixing, the organic layer was separated, dried over anhydrous potassium carbonate, filtered and evaporated to give 18.20 g of 1-[[1-methyl-5-[[4-[2-(1-methylethoxy)phenyl]-1 -piperazinyl]methyl]-lH-pyrrol-2-yl]methyl]-2- piperidinone as a Yellow oil. This material (2.50 g) was dissolved in 6 mL ethanol and treated with 0.68 g of oxalic acid. The mixture was heated to effect solution, cooled and ether added until just cloudy. After cooling in an ice bath, a white solid was obtained by filtration. This was recrystallized twice from ethanol-ether using activated charcoal to give the oxalate salt, mp 139.5-140.5° C. (Ho).
