Hydrogen Bromide → 6-Bromo-4-methoxypyrazolo[1,5-a]pyridine

HRID 1895888Notes

Reaction equation

HRID 1895888 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([O:16][CH3:17])[C:5]2[N:6]([N:8]=[CH:9][C:10]=2C(OCC)=O)[CH:7]=1.Br.[OH-].[Na+]>C(OCC)(=O)C>[Br:1][C:2]1[CH:3]=[C:4]([O:16][CH3:17])[C:5]2[N:6]([N:8]=[CH:9][CH:10]=2)[CH:7]=1

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 14798Sodium HydroxideHCID 58385978HCID 58385978, compound

Product 1

HCID 446228256-Bromo-4-methoxypyrazolo[1,5-a]pyridineYield 60%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Conditions

Temperature
0 °C

Procedure

A solution of ethyl 6-bromo-4-methoxylpyrazolo[1,5-a]pyridine-3-carboxylate (15, 5.2 g, 18.24 mmol) in HBr (100 ml, 884 mmol) was heated to 100° C. for 1 hour. After cooling to 0° C., 1M NaOH (182 ml, 912 mmol) was used to neutralize the solution. The reaction mixture was diluted in ethyl acetate, washed with saturated aqueous sodium hydroxide (1N) and brine then dried over Na2SO4. After filtration and concentration, the residue was purified by column chromatography (0-35% EtOAc in hexanes, linear gradient) to give 6-bromo-4-methoxypyrazolo[1,5-a]pyridine (16, 2.475 g, 10.90 mmol, 60% yield). MS APCI: [M+H]+ m/z 228.1.

Workup

  1. washwashed with saturated aqueous sodium hydroxide (1N) and brine
  2. dry with materialthen dried over Na2SO4
  3. filtrationAfter filtration and concentration
  4. customthe residue was purified by column chromatography (0-35% EtOAc in hexanes, linear gradient)

Sources & evidence

ORD record
ord-d168eb31c2a24be0ab07b424e4fef363
Source dataset
uspto-grants-2013_08
Patent number
US08518911B2

Reaction notes

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