Reaction #465963

Reaction equation

methyl 4-amino-3,6-dichloropyridine-2-carboxylate

bromine

→

4-amino-3,6-dichloro-5-bromopyridine-2-carboxylic acid

Yield 91.0%

Solvents

sulfuric acid

Conditions

Workup

1. 1
   Temperatureto cool to room temperature
2. 2
   Extractionextracted with EtOAc (4×500 mL)
3. 3
   DryingThe combined organic extracts were dried (MgSO4)
4. 4
   Filtrationfiltered
5. 5
   Concentrationconcentrated
6. 6
   Otherto yield a brown solid
7. 7
   OtherThe crude product was purified via reverse phase HPLC (50% acetonitrile/water)

Procedure

To a solution of methyl 4-amino-3,6-dichloropyridine-2-carboxylate (18 g, 81 mmol) in 100 mL fuming sulfuric acid was added bromine (15 mL, excess). The resulting mixture was heated to 70° C. for 30 min, then allowed to cool to room temperature. This material was poured into ice water (1000 mL) and extracted with EtOAc (4×500 mL). The combined organic extracts were dried (MgSO4), filtered and concentrated to yield a brown solid. The crude product was purified via reverse phase HPLC (50% acetonitrile/water) to give 21 g of 4-amino-3,6-dichloro-5-bromopyridine-2-carboxylic acid as a white solid (91% yield); mp 201-202° C.

Source