Reaction #5524

Reaction equation

2-amino-6-chloropyridine

ethyl bromopyruvate

→

desired product

Yield 67.7%

2-ethoxycarbonyl-5-chloroimidazo[1,2-a]pyridine

Yield 67.7%

Solvents

ethanol

Conditions

Workup

1. 1
   Temperatureat reflux for 4 hours
2. 2
   OtherAfter the solvent was removed
3. 3
   workup.ADDITIONchloroform was added to the residue, which
4. 4
   Washwas washed in turn with saturated sodium bicarbonate and saturated saline
5. 5
   Dryingdried over anhydrous magnesium sulfate
6. 6
   ConcentrationAfter the solvent was concentrated
7. 7
   workup.ADDITIONn-hexane was added to the mixture
8. 8
   OtherThen, the crystals precipitated
9. 9
   Filtrationwere filtered off
10. 10
    Washwashed with n-hexane

Procedure

A solution of 2-amino-6-chloropyridine (6.43 g, 50 mmoles) and ethyl bromopyruvate (9.75 g, 50 mmoles) in ethanol (150 ml) was heated at reflux for 4 hours. After the solvent was removed, chloroform was added to the residue, which was washed in turn with saturated sodium bicarbonate and saturated saline, and then dried over anhydrous magnesium sulfate. After the solvent was concentrated, n-hexane was added to the mixture. Then, the crystals precipitated were filtered off and washed with n-hexane to obtain 7.60 g of the desired product (67.6%, pale yellow crystals).

Source