Reaction #2200601

Reaction equation

methyl 3-chloro-6-(methoxymethyl)pyridine-2-carboxylate 1-oxide

phosphorus oxychloride

→

methyl 3,4-dichloro-6-(methoxymethyl)pyridine-2-carboxylate

Yield 98.3%

Solvents

acetonitrile

Conditions

Workup

1. 1
   Temperatureat reflux for 4 hours
2. 2
   Concentrationwas concentrated to dryness in vacuo
3. 3
   workup.ADDITIONThe residue was diluted with ethyl ether
4. 4
   Washcarefully washed with saturated NaHCO3 solution
5. 5
   OtherThe organic layer was separated
6. 6
   Extractionthe aqueous layer was extracted with ethyl ether
7. 7
   Dryingthe solution was dried (MgSO4)
8. 8
   Filtrationfiltered
9. 9
   Concentrationconcentrated to dryness

Procedure

To a solution of methyl 3-chloro-6-(methoxymethyl)pyridine-2-carboxylate 1-oxide (1.64 g, 7.08 mmol) in acetonitrile (28 mL) was added phosphorus oxychloride (1.32 mL, 14.16 mmol) and the mixture stirred at reflux for 4 hours. After cooling to room temperature the mixture was concentrated to dryness in vacuo. The residue was diluted with ethyl ether and carefully washed with saturated NaHCO3 solution. The organic layer was separated and the aqueous layer was extracted with ethyl ether. After the organic layers were combined, the solution was dried (MgSO4), filtered and concentrated to dryness to give crude methyl 3,4-dichloro-6-(methoxymethyl)pyridine-2-carboxylate (1.74 g) as a yellow oil; 1H NMR (CDCl3): δ 7.70 (s, 1H), 4.60 (s, 2H), 4.00 (s, 3H), 3.40 (s, 3H).

Source