Reaction #502101

Reaction equation

ethyl[2-imino-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyridin-1-yl]acetate hydrobromide

POCl3

→

compound

2-Chloro-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine

Conditions

Workup

1. 1
   Temperaturecooled to ambient temperature
2. 2
   Concentrationconcentrated under reduced pressure
3. 3
   Otheris taken up between dichloromethane and water at 0° C.
4. 4
   workup.ADDITIONa 30% aqueous solution of NH4OH is added until a basic pH
5. 5
   Otheris obtained
6. 6
   OtherThe organic phase is separated
7. 7
   Dryingdried over magnesium sulphate
8. 8
   Concentrationconcentrated under reduced pressure

Procedure

8.78 g of ethyl[2-imino-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyridin-1-yl]acetate hydrobromide in 20 ml of POCl3 are placed in a round-bottomed flask. The reaction mixture is heated at 105° C. for 16 h, cooled to ambient temperature and concentrated under reduced pressure. The residue is taken up between dichloromethane and water at 0° C., and a 30% aqueous solution of NH4OH is added until a basic pH is obtained. The organic phase is separated, dried over magnesium sulphate and concentrated under reduced pressure. 4.3 g of compound are obtained.

Source