Reaction #5525

Reaction equation

cysteamine hydrochloride

sodium hydride

5-chloro-2-methylimidazo[1,2-a]pyridine

→

desired product

Yield 53.6%

5-[2-(amino)ethylthio]-2-methylimidazo[1,2-a]pyridine

Yield 53.6%

Solvents

ethanol

Conditions

Workup

1. 1
   Temperaturecooling
2. 2
   workup.STIRRINGthe mixture was stirred for 5 minutes
3. 3
   Temperatureby heating
4. 4
   Temperatureat reflux for 3 hours
5. 5
   workup.DISTILLATIONAfter the solvent was distilled off
6. 6
   workup.ADDITIONchloroform was added to the residue which
7. 7
   Washwas washed with 1N-NaOH
8. 8
   Dryingdried over anhydrous potassium carbonate
9. 9
   workup.DISTILLATIONAfter the solvent was distilled off
10. 10
    Otherthe residue was purified by column chromatography (eluent: ethyl acetate/ethanol/triethylamine=6:2:1)

Procedure

To a suspension of cysteamine hydrochloride (2.95 g, 26 mmoles) in ethanol (100 ml) was added 60% sodium hydride (oily; 2.08 g, 26 mmoles) with stirring under ice-cooling and the mixture was stirred for 5 minutes. 5-chloro-2-methylimidazo[1,2-a]pyridine (3.33 g, 20 mmoles) was added to the mixture, followed by heating at reflux for 3 hours. After the solvent was distilled off, chloroform was added to the residue which was washed with 1N-NaOH and dried over anhydrous potassium carbonate. After the solvent was distilled off, the residue was purified by column chromatography (eluent: ethyl acetate/ethanol/triethylamine=6:2:1) to obtain 2.2 g of the desired product (53.6%, brown oily product).

Source