Hydrochloric Acid → 4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine hydrochloride

Temperature

80 °C

Histamine dihydrochloride (61.9 g, 336 mmol) was dissolved in a solution of NaOH (33.6 g, 841 mmol) in water (125 mL) and MeOH (500 mL), and isobutyraldehyde (61.4 mL, 672 mmol) was added. The reaction mixture was heated under reflux at 80° C. for 24 h, cooled to room temperature, the pH was adjusted to 7 with 1 M aq HCl solution (250 mL) and the solvents were removed in vacuo. The residue was dissolved in warm MeOH (300 mL), allowed to stand for 1 h, filtered and the solvents were removed in vacuo. The residue was stirred in MeOH (50 mL) and acetone (400 mL) for 2 h and was cooled to 4° C. for 2 h. The resulting precipitate was filtered and washed with acetone (100 mL) to give 4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine hydrochloride (33.0 g, 48.7%) as a white solid.

1. additionwas added
2. temperatureThe reaction mixture was heated
3. temperaturecooled to room temperature
4. customthe solvents were removed in vacuo
5. dissolutionThe residue was dissolved in warm MeOH (300 mL)
6. filtrationfiltered
7. customthe solvents were removed in vacuo
8. waitacetone (400 mL) for 2 h
9. temperaturewas cooled to 4° C. for 2 h
10. filtrationThe resulting precipitate was filtered
11. washwashed with acetone (100 mL)

ORD record

ord-8e6521e7df6b4560b40b261730693ca8

Source dataset

uspto-grants-2013_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08569338B2