Piperazine → Piperazine, 2-pyridylethyl-

Temperature

22.5 °C

A solution of piperazine: 2HCl:H2O (241 g, 1332 mmol) in water (245 mL) was heated at 60-70° C. Vinyl pyridine (38.0 g, 333 mmol) was slowly added during of 45-60 min at 60-70° C. Heating was continued for 45-60 min at 60-70° C. The reaction mixture was cooled to 20-25° C. The pH was slowly adjusted to 8.0-8.5 with a solution of aqueous sodium hydroxide (40.0% w/w) during 45-60 min at 20-30° C. The reaction mixture was washed with toluene (2×175 mL). The aqueous layer was slowly adjusted to pH 12.0-12.5 with a solution of aqueous NaOH (40.0% w/w) during 45-60 min at 20-30° C. and again washed with toluene (175 mL). The aqueous layer was extracted with n-butanol (2×210 mL). n-Butanol was removed under reduced pressure until the residual volume reached 100 mL. n-Butanol was swapped completely with xylene (2×210 mL) until the residual volume reached 100 mL. Xylene (35 mL) was added at 75-85° C. and then cooled to 20-25° C. The reaction solution was maintained for 1.0 h at 20-25° C. and then filtered through celite and the celite washed with xylene (35 mL). The combined xylene solution was used in the next step without isolation of the product.

1. temperatureHeating
2. washThe reaction mixture was washed with toluene (2×175 mL)
3. waitThe aqueous layer was slowly adjusted to pH 12.0-12.5 with a solution of aqueous NaOH (40.0% w/w) during 45-60 min at 20-30° C.
4. washagain washed with toluene (175 mL)
5. extractionThe aqueous layer was extracted with n-butanol (2×210 mL)
6. customn-Butanol was removed under reduced pressure until the residual volume
7. additionXylene (35 mL) was added at 75-85° C.
8. temperaturecooled to 20-25° C
9. temperatureThe reaction solution was maintained for 1.0 h at 20-25° C.
10. filtrationfiltered through celite
11. washthe celite washed with xylene (35 mL)

ORD record

ord-b7890fb52d4d4f80bfc8f6813320da7c

Source dataset

uspto-grants-2013_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08367676B2