Phosphorus oxychloride → 2,4-Dichloro-5-nitropyridine

HRID 1986345Notes

Reaction equation

HRID 1986345 reaction equation
[Cl:1][C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][N:5]=[C:4](O)[CH:3]=1.O=P(Cl)(Cl)[Cl:14]>C1(C)C=CC=CC=1>[Cl:14][C:4]1[CH:3]=[C:2]([Cl:1])[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][N:5]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178526833HCID 178526833, compound

Product 1

HCID 122757652,4-Dichloro-5-nitropyridineYield 74%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
60 °C

Procedure

The product from Step 2 (40.0 g, 229 mmol) was suspended in toluene (300 mL) and POCl3 (65 mL, 697 mmol) was added over 10 min, then the mixture was heated to relux for 6 h then cooled to 60° C. and allowed to stir overnight at that temperature. The heterogeneous mixture was cooled and concentrated, the residue was carefully made basic with aq. K2CO3 solution and extracted with EtOAc. The organic layers were combined, washed with H2O and brine, dried (Na2SO4), filtered and the filtrate was concentrated to give an oil. The crude oil was passed through a plug of silica gel (50% EtOAc in hexanes) to give the title compound (32.5 g, 74%) as an orange oil which solidified on standing. MS (ES+) m/e 194 [M+H]+.

Workup

  1. temperaturethe mixture was heated
  2. temperatureThe heterogeneous mixture was cooled
  3. concentrationconcentrated
  4. extractionextracted with EtOAc
  5. washwashed with H2O and brine
  6. dry with materialdried (Na2SO4)
  7. filtrationfiltered
  8. concentrationthe filtrate was concentrated
  9. customto give an oil

Sources & evidence

ORD record
ord-345f5606619a461f9d01f40e40d43cb8
Source dataset
uspto-grants-2009_06
Patent number
US07547779B2

Reaction notes

Loading…