Water → 4-Phenyl-1-(3'-sulfopropyl)-1,2,3,6 tetrahydropyridine

To a solution of 4-phenylpyridine (15.5 g, 0.1 mol) in acetone (100 mL) was added 1,3-propane sultone (12.2 g, 0.1 mol) at room temperature. The mixture was then heated at reflux temperature overnight. The resultant suspension was cooled to room temperature. The solid was collected by filtration and washed with acetone. To a solution of the solid (31 g) in methanol (500 mL) was added sodium borohydride (10 g, 260 mmol) portionwise, and the mixture was stirred at room temperature for 2 h. Distilled water (50 mL) was added to destroy the excess of sodium borohydride. The mixture was diluted with methanol (200 ml), and neutralized with Amberlite IR-120 ion-exchange resin (H+ form, 300 g). A white precipitate was formed. The precipitate and the resin were removed by filtration and treated with distilled water (400 mL) at ˜100 ° C. The mixture was filtered and the residual resin was washed with hot distilled water (2×200 mL). The filtrates and washings were combined and concentrated to dryness. The residue was co-evaporated with methanol (3×200 mL), and then recrystallized from ethanol-water {8:2 (v/v)} to afford 4-phenyl-1-(3′-sulfopropyl)-1,2,3,6-tetrahydropyridine as white crystals (26 g, 93%). The 1H and 13C NMR spectra were in agreement with the structure.

1. temperatureThe mixture was then heated
2. temperatureat reflux temperature overnight
3. filtrationThe solid was collected by filtration
4. washwashed with acetone
5. customto destroy the excess of sodium borohydride
6. additionThe mixture was diluted with methanol (200 ml)
7. customA white precipitate was formed
8. customThe precipitate and the resin were removed by filtration
9. additiontreated with distilled water (400 mL) at ˜100 ° C
10. filtrationThe mixture was filtered
11. washthe residual resin was washed
12. distillationwith hot distilled water (2×200 mL)
13. concentrationconcentrated to dryness
14. customrecrystallized from ethanol-water {8:2 (v/v)}

ORD record

ord-172ea02c9ec545a6b257880452a2c0f0

Source dataset

uspto-grants-2003_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06562836B1