Oxalic Acid → 3-Methyl-2-[3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)propyl]-1-isoindolinone oxalate

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Reaction Steps

2.5 g of 2-acetylbenzoic acid is added to a solution of 3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)-1-aminopropane (7.8 g) in acetonitrile (90 cc) at a temperature close to 20° C. in the course of 10 minutes. Agitation is continued for 4 hours then 7.6 g of 3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)-1-aminopropane hydrochloride is added in the course of 30 minutes. Then 1.2 g of sodium cyanoborohydride is added to the suspension obtained, in the course of 5 minutes. Agitation is continued for 16 hours. The suspension is filtered and the precipitate washed with acetonitrile (20 cc). The organic extracts are combined, diluted with methylene chloride (200 cc) then washed with distilled water (120 cc), dried over anhydrous magnesium sulphate, treated with animal charcoal, filtered and concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. The residue obtained is poured onto alumina (750 g) contained in a column of 6 cm diameter. Elution is carried out with ethyl acetate (1000 cc) and the corresponding eluates are eliminated. Then elution is carried out with a mixture of ethyl acetate and methanol (98-2 by volume) (1000 cc) and the corresponding eluates are evaporated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 50° C. The residue obtained is dissolved in methyl ethyl ketone (20 cc). A solution of oxalic acid (0.3 g) in methyl ethyl ketone (10 cc) is added and agitation continued for 1 hour at a temperature close to 20° C. The precipitate formed is separated by filtration and recrystallized from boiling acetonitrile (80 cc). 0.9.g of 3-methyl-2-[3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)propyl]-1-isoindolinone oxalate are thus obtained, melting at 147° C.

Provenance & Evidence