Hydrochloric Acid → Diethyl 6-chloropyridine-2,3-dicarboxylate

HRID 1741619Notes

Reaction equation

HRID 1741619 reaction equation
[N+:1]1([O-])[CH:6]=[CH:5][CH:4]=[C:3]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[C:2]=1[C:12]([O:14][CH2:15][CH3:16])=[O:13].[ClH:18]>P(Cl)(Cl)(Cl)=O>[Cl:18][C:6]1[N:1]=[C:2]([C:12]([O:14][CH2:15][CH3:16])=[O:13])[C:3]([C:7]([O:9][CH2:10][CH3:11])=[O:8])=[CH:4][CH:5]=1

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 21847052diethyl pyridine-2,3-dicarboxylate-N-oxide

Product 1

HCID 15451780Diethyl 6-chloropyridine-2,3-dicarboxylate

Reagents, catalysts & solvents 1

HCID 24813Phosphorus oxychlorideSolvent

Procedure

A mixture of 75.6 g of diethyl pyridine-2,3-dicarboxylate-N-oxide and 150 mL of phosphorous oxychloride is warmed slowly in a large reaction vessel equipped with a reflux condenser and gas scrubber. Caution: exothermic reaction! At about 70°, an exothermic reaction ensues with vigorous liberation of hydrogen chloride gas. The reaction is heated at reflux after the exotherm subsides for an additional hour. The reaction is cooled and concentrated in vacuo to a syrup. This material is dissolved in methylene chloride, washed cautiously with saturated sodium bicarbonate, dried and concentrated in vacuo to give the desired product as an oil. An analytical sample is obtained by chromatography on silica gel using 2:1 petroleum ether-ether as eluant to give the product as a colorless oil.

Workup

  1. temperatureis warmed slowly in a large reaction vessel
  2. customequipped with a reflux condenser
  3. customCaution: exothermic reaction
  4. customAt about 70°, an exothermic reaction
  5. temperatureThe reaction is heated
  6. temperatureat reflux after the exotherm subsides for an additional hour
  7. temperatureThe reaction is cooled
  8. concentrationconcentrated in vacuo to a syrup
  9. dissolutionThis material is dissolved in methylene chloride
  10. washwashed cautiously with saturated sodium bicarbonate
  11. customdried
  12. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-4cefb71ec94b415b9bb41c134134c8f8
Source dataset
uspto-grants-1994_08
Patent number
US05334576

Reaction notes

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