Ethyl orthoformate → 4-Chloro-7-cyclopentyl-7H-imidazo[4,5-c]pyridazine
Reaction equation
[Cl:1][C:2]1[C:3]([NH2:14])=[C:4]([NH:8][CH:9]2[CH2:13][CH2:12][CH2:11][CH2:10]2)[N:5]=[N:6][CH:7]=1.[CH2:15](OC(OCC)OCC)C>>[Cl:1][C:2]1[C:3]2[N:14]=[CH:15][N:8]([CH:9]3[CH2:13][CH2:12][CH2:11][CH2:10]3)[C:4]=2[N:5]=[N:6][CH:7]=1Participants
3
Procedure
A mixture of 5-chloro-N-3-cyclopentylpyridazine-3,4-diamine (Preparation 12, 1.2 g, 5.64 mmol) and triethylorthoformate (10 mL) were heated to reflux for 1.5 hours. The reaction mixture was allowed to cool to room temperature, concentrated in vacuo and triturated with EtOAc (20 mL). The solid was filtered and the filtrate was reduced to dryness. The crude material was purified by silica gel column chromatography eluting with EtOAc to afford the title compound as a yellow solid in 51% yield, 902 mg.
Workup
- temperaturewere heated
- temperatureto reflux for 1.5 hours