Ethyl orthoformate → 4-chloro-7-ethyl-7H-imidazo(4,5-c)pyridazine

Reaction equation

[Cl:1][C:2]1[C:3]([NH2:11])=[C:4]([NH:8][CH2:9][CH3:10])[N:5]=[N:6][CH:7]=1.[CH2:12](OC(OCC)OCC)C>>[Cl:1][C:2]1[C:3]2[N:11]=[CH:12][N:8]([CH2:9][CH3:10])[C:4]=2[N:5]=[N:6][CH:7]=1

Participants

Reactant 2

HCID 31214Ethyl orthoformate

HCID 867232305-Chloro-N3-ethyl-3,4-pyridazinediamine

Product 1

HCID 552967654-chloro-7-ethyl-7H-imidazo(4,5-c)pyridazineYield 45%

Procedure

A mixture of 5-chloro-N3-ethyl-pyridazine-3,4-diamine (Preparation 7, 10.0 g, 58 mmol) and triethylorthoformate (60 mL) were heated to reflux for 4 hours. The reaction mixture was concentrated in vacuo and the residue was dissolved in EtOAc (50 mL) and filtered. The filter cake was washed with EtOAc and then the organic layers were washed with saturated brine solution, dried over Na2SO4 and concentrated in vacuo to afford the title compound as a yellow solid in 45% yield, 4.8 g.

Workup

temperaturewere heated
temperatureto reflux for 4 hours
concentrationThe reaction mixture was concentrated in vacuo
dissolutionthe residue was dissolved in EtOAc (50 mL)
filtrationfiltered
washThe filter cake was washed with EtOAc
washthe organic layers were washed with saturated brine solution
dry with materialdried over Na2SO4
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-9682482d34b54dac85b63bf0e39d2623
Source dataset: uspto-grants-2015_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08952008B2

Reaction notes

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