Phosphorus oxychloride → 2-Chloro-5,6-dimethyl-3-nitropyridine

HRID 1888000Notes

Reaction equation

HRID 1888000 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]([N+:10]([O-:12])=[O:11])[C:5](O)=[N:6][C:7]=1[CH3:8].P(Cl)(Cl)([Cl:15])=O>[Cl-].C([N+](CC)(CC)CC)C1C=CC=CC=1.C(#N)C>[Cl:15][C:5]1[C:4]([N+:10]([O-:12])=[O:11])=[CH:3][C:2]([CH3:1])=[C:7]([CH3:8])[N:6]=1

Participants

5

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178428771HCID 178428771, compound

Product 1

HCID 100811492-Chloro-5,6-dimethyl-3-nitropyridineYield 92.5%

Reagents, catalysts & solvents 2

HCID 66133Benzyl triethylammonium chlorideCatalystHCID 6342AcetonitrileSolvent

Procedure

A mixture of 5,6-dimethyl-3-nitropyridin-2-ol (7.09 g, 42.2 mmol), benzyltriethylammonium chloride (4.82 g, 21.1 mmol) and acetonitrile (90 mL) at room temperature was slowly treated with phosphorus oxychloride (11.8 mL, 125 mmol) then heated to reflux and stirred overnight. The mixture was concentrated under reduced pressure and treated with ice-water (220 mL) and basified with concentrated ammonium hydroxide (100 mL). The mixture was extracted with dichloromethane (3×100 mL) and the combined extracts were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to yield 2-chloro-5,6-dimethyl-3-nitropyridine (7.28 g, 92%). Mp. 72-76° C.; 400 M Hz 1H NMR (CDCl3) δ: 8.01 (s, 1H), 2.58 (s, 3H), 2.38 (s, 3H).

Workup

  1. temperaturethen heated
  2. temperatureto reflux
  3. concentrationThe mixture was concentrated under reduced pressure
  4. additiontreated with ice-water (220 mL)
  5. extractionThe mixture was extracted with dichloromethane (3×100 mL)
  6. dry with materialthe combined extracts were dried over anhydrous sodium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-e58d178fc0e244bdaac91e0df5133694
Source dataset
uspto-grants-2013_08
Patent number
US08501770B2

Reaction notes

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