Phosgene → Pirogliride Tartrate

Participants

Reaction Steps

To a cooled solution of 1.98 g (0.02 mole) of 1-methyl-2-pyrrolidone in dry toluene is added 3.95 g (0.04 mole) of phosgene. The resulting mixture is allowed to stir under N2 to room temperature over 45 minutes to give white crystals. The excess COCl2 and solvent are removed with the aid of a filter stick (under N2). Fresh toluene is added, then removed under vacuum in order to remove residual phosgene. The crystals are washed in this way with fresh toluene two more times and then dissolved in dry CH2Cl2 followed by the addition of 1.89 g (0.01 mole) of N-phenyl-1-pyrrolidinecarboximidamide and 1.01 g (0.01 mole) of triethylamine. The resulting mixture is stirred overnight under N2. The mixture is taken to dryness in vacuo, the residue dissolved in CH2Cl2 and the latter solution treated with NaOH (50%) in ice. The organic layer, which contains the free base form of the product, is separated, dried over anhydrous K 2 CO3, filtered and taken to dryness in vacuo affording an oily residue. The oil is dissolved in isopropanol followed by addition of L-(+)-tartaric acid to about pH 6-7. The resulting crystals are recrystallized from isopropanol to give pure product, N-(1-methyl-2-pyrrolidinylidene)-N'-phenyl-1-pyrrolidinecarboximidamide L-(+)-tartrate, m.p. 155°-156° C.

Provenance & Evidence