3-Chloro-6-methylpyridazine → tert-butyl 2-(6-methylpyridazin-3-yl)-2,4,6,7-tetrahydro-5H-pyrazolo[4,3-c]pyridine-5-carboxylate

Temperature

120 °C

A mixture of tert-butyl 1,4,6,7-tetrahydro-5H-pyrazolo[4,3-c]pyridine-5-carboxylate (3.72 g, 16.67 mmol), 3-chloro-6-methylpyridazine (3.2 g, 24.92 mmol), Pd2(dba)3 (760 mg, 0.83 mmol), tBuXPhos (705 mg, 1.66 mmol) and tBuONa (1.99 g, 20.77 mmol) in toluene (90 mL) is degassed by argon and heated at 120° C. in a sealed tube overnight. EtOAc (200 mL) and water (250 mL) are added and the layers are separated. The organic layer is washed with water (200 mL) and then brine (200 mL), dried and evaporated. Purification of the residue by flash column with hexane/EtOAc (2:1) gives a white solid that is a mixture of two regioisomers. Recrystallization of the solid from hexane/EtOAc (1:1) gives the title compound as white needles. MS (M+1): 316.2.

1. customis degassed by argon
2. additionEtOAc (200 mL) and water (250 mL) are added
3. customthe layers are separated
4. washThe organic layer is washed with water (200 mL)
5. dry with materialbrine (200 mL), dried
6. customevaporated
7. customPurification of the residue by flash column with hexane/EtOAc (2:1)
8. customgives a white solid
9. additiona mixture of two regioisomers
10. customRecrystallization of the solid from hexane/EtOAc (1:1)

ORD record

ord-fa56d7a485d34fa0aadcd433f786903d

Source dataset

uspto-grants-2010_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07795262B2