Methanethiol → 3-Methylthio-2-[3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)propyl]-1-isoindolinone oxalate

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Reaction Steps

5 cc of methylmercaptan is added to a solution of methyl 2-formylbenzoate (3.6 g) and 3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)-1-aminopropane (9.6 g)in tetrahydrofuran (255 cc) in an autoclave, at a temperature close to -20° C. in the course of 5 minutes. The solution is heated to a temperature close to 60° C. for 4 hours. After cooling to a temperature close to 20° C., the solution is poured into 1N sodium hydroxide (300 cc) and washed with distilled water (3×500 cc). The organic extract is dried over anhydrous magnesium sulphate, filtered and concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. The residue obtained is dissolved in ethyl acetate (20 cc) and poured onto silica (750 g) contained in a column of 8 cm diameter. Elution is carried out with ethyl acetate. The first 3400 cc are eliminated and the next 3100 cc are evaporated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. The residue obtained is dissolved in methyl ethyl ketone (70 cc). A solution of oxalic acid (1.7 g) in methyl ethyl ketone (20 cc) is added and agitation continued for 1 hour at a temperature close to 20° C. The precipitate formed is separated by filtration. 5.9 g of 3-methylthio-2-[3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)propyl]-1-isoindolinone oxalate are thus obtained, melting at 169° C.

Provenance & Evidence