Hydrogen Bromide → Imidazo(1,2-b)pyridazine, 6-chloro-

HRID 2205193Notes

Reaction equation

HRID 2205193 reaction equation
C(OC(O[CH2:8][CH3:9])CBr)C.Br.C(=O)(O)[O-].[Na+].[NH2:16][C:17]1[N:18]=[N:19][C:20]([Cl:23])=[CH:21][CH:22]=1>C(O)(C)C>[Cl:23][C:20]1[CH:21]=[CH:22][C:17]2[N:18]([CH:8]=[CH:9][N:16]=2)[N:19]=1

Participants

6

Reactant 4

HCID 260Hydrogen BromideHCID 216436-Amino-3-chloropyridazineHCID 74852Ethane, 2-bromo-1,1-diethoxy-HCID 516892Sodium Bicarbonate

Product 1

HCID 138828Imidazo(1,2-b)pyridazine, 6-chloro-Yield 86%

Reagents, catalysts & solvents 1

HCID 3776IsopropanolSolvent

Procedure

Bromoacetaldehyde diethylacetal (13.7 g, 69.5 mmol, 1.8 equiv) was added to hydrobromic acid (4.0 mL) and heated to reflux for 1.5 h. The reaction mixture was cooled to rt then poured into a reaction flask containing excess sodium bicarbonate in isopropanol. The solution was stirred for 3 min and then filtered. To the mother liquor was added 3-amino-6-chloropyridazine (5.0 g, 38.6 mmol, 1.0 equiv) and heated to reflux for 2 h. The reaction mixture was quenched with water and extracted with ethyl acetate. Purification using column chromatography gave 5.1 g of the brown solid, 86%: 1H NMR (400 MHz, CDCl3) δ 7.89 (s, 1H), 7.88 (d, J=9.3 Hz, 1H), 7.74 (s, 1H), 7.01 (d, J=9.3 Hz, 1H).

Workup

  1. temperatureheated
  2. temperatureto reflux for 1.5 h
  3. additionthen poured into a reaction flask
  4. filtrationfiltered
  5. temperatureheated
  6. temperatureto reflux for 2 h
  7. customThe reaction mixture was quenched with water
  8. extractionextracted with ethyl acetate
  9. customPurification

Sources & evidence

ORD record
ord-051b42bedffa444db426b8e526b34316
Source dataset
uspto-grants-2016_06
Patent number
US09370515B2

Reaction notes

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