3-Methylglutaric anhydride → 4-Methyl-1-[[3-[[1-[2-(1-methylethoxy)phenyl]-4-piperazinyl]methyl]phenyl]methyl]piperidine-2,6-dione

Participants

Reaction Conditions

Reaction Steps

A solution of 3-[[1-[2-(1-methylethoxy)phenyl]-4-piperazinyl]methyl]benzyl amine (2.32 g, 6.84 mmol; prepared as described in Example 7), 3-methylglutaric anhydride (0.88 g, 6.84 mmol), and THF (20 mL) was stirred at room temperature for 3 h and then concentrated to an oily residue. This material was dissolved in acetic anhydride (25 mL), heated at 100° C. for 4 h, cooled, and added slowly to saturated aqueous NaHCO3. Extraction with CH2Cl2, separation of the organic layer, drying, filtration and evaporation afforded an oil. This material was chromatographed on flash grade silica using 97:3/CH2Cl2 :MeOH to give 4-methyl-1-[[3-[[1-[2-(1-methylethoxy)phenyl]-4-piperazinyl]methyl]phenyl]methyl]piperidine-2,6-dione as an oil. This was dissolved in ether and added to ethereal HCl causing a solid to form. Filtration afforded 4-methyl-1-[[3-[[ 1-[2-(1-methylethoxy)phenyl]-4-piperazinyl]methyl]phenyl]methyl]piperidine-2,6-dione dihydrochloride (1.43 g, 40%), m.p. 196°-200° C. H-1 NMR and mass spectral analysis supported the assigned structure.

Provenance & Evidence