Triethyl orthoacetate → 6-bromo-2,3-dimethyl-3H-imidazo[4,5-b]pyridine

HRID 879542Notes

Reaction equation

[Br:1][C:2]1[CH:3]=[C:4]([NH2:10])[C:5]([NH:8][CH3:9])=[N:6][CH:7]=1.CC(O[CH2:20][CH3:21])(OCC)OCC>CC(O)=O>[Br:1][C:2]1[CH:3]=[C:4]2[N:10]=[C:20]([CH3:21])[N:8]([CH3:9])[C:5]2=[N:6][CH:7]=1

Participants

Conditions

Temperature: 80 °C

Procedure

To a suspension of 5-bromo-N2-methylpyridine-2,3-diamine (510 mg, 2.51 mmol) in AcOH (20 mL) was added MeC(OEt)3 (1 mL) and the solution was warmed to 80° C. for 2 hours. The reaction mixture was allowed to cool to room temperature and was concentrated in vacuo. The crude residue was purified by silica gel column chromatography (0-25% THF/CH2Cl2 gradient) to afford the desired product. 1H NMR (400 MHz, CDCl3) δ 8.36 (d, J=1.8 Hz, 1H), 8.06 (d, J=1.9 Hz, 1H), 3.80 (s, 3H), 2.65 (s, 3H).

Workup

temperatureto cool to room temperature
concentrationwas concentrated in vacuo
customThe crude residue was purified by silica gel column chromatography (0-25% THF/CH2Cl2 gradient)

Sources & evidence

ORD record: ord-7171941344074b899a7173a9c0b84513
Source dataset: uspto-grants-2015_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08987250B2

Reaction notes

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