Sodium borohydride → Imidazo[1,2-a]pyridine-7-methanol

HRID 985533Notes

Reaction equation

HRID 985533 reaction equation
C[O:2][C:3]([C:5]1[CH:10]=[CH:9][N:8]2[CH:11]=[CH:12][N:13]=[C:7]2[CH:6]=1)=O.[BH4-].[Na+]>CO>[NH3:8].[N:13]1[CH:12]=[CH:11][N:8]2[CH:9]=[CH:10][C:5]([CH2:3][OH:2])=[CH:6][C:7]=12

Participants

5

Reactant 2

HCID 4311764Sodium borohydrideHCID 15096964Methyl imidazo(1,2-a)pyridine-7-carboxylate

Product 2

HCID 222AmmoniaHCID 11051824Imidazo[1,2-a]pyridine-7-methanolYield 193.6%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a cooled (0° C.) solution of imidazo[1,2-α]pyridine-7-carboxylic acid methyl ester (2.15 g, 12.2 mmol) in methanol (50 ml) was added sodium borohydride (4.64 g, 12.2 mmol) in portions over 15 min. The mixture was heated under reflux for 3 h, cooled to ambient temperature and evaporated to dryness. The residue was dissolved in dichloromethane:methanol (300 ml of a 1:1 mixture) and pre-adsorbed onto silica. Purification by silica gel chromatography eluting with dichloromethane/methanol/conc. ammonia (95:5:0.5) gave imidazo[1,2-α]pyridin-7-ylmethanol (1.75 g, 77%) as a colourless oil. 1H NMR (400 MHz, CDCl3) δH 4.71 (2H, s), 6.79 (1H, dd, J 7 and 1), 7.37 (1H, s), 7.52 (1H, s), 7.56 (1H, d, J 1), 8.05 (1H, d, J 7).

Workup

  1. temperatureThe mixture was heated
  2. temperatureunder reflux for 3 h
  3. customevaporated to dryness
  4. dissolutionThe residue was dissolved in dichloromethane
  5. customPurification by silica gel chromatography
  6. washeluting with dichloromethane/methanol/conc

Sources & evidence

ORD record
ord-9e21e14808374180a6bc5dab63c528ff
Source dataset
uspto-grants-2005_03
Patent number
US06872731B2

Reaction notes

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