Phenylphosphonic dichloride → 2,5-Dichloro-6-methyl-3-pyridinecarboxylic acid

HRID 247266Notes

Reaction equation

HRID 247266 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([C:10]([OH:12])=[O:11])[C:5](O)=[N:6][C:7]=1[CH3:8].C1(P(Cl)([Cl:21])=O)C=CC=CC=1>O>[Cl:21][C:5]1[C:4]([C:10]([OH:12])=[O:11])=[CH:3][C:2]([Cl:1])=[C:7]([CH3:8])[N:6]=1

Participants

4

Reactant 2

HCID 69990Phenylphosphonic dichlorideHCID 178433474HCID 178433474, compound

Product 1

HCID 140985062,5-Dichloro-6-methyl-3-pyridinecarboxylic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
135 °C

Procedure

To 5 g (0.027 mole) of 5-chloro-2-hydroxy-6-methyl-3-pyridinecarboxylic acid was added 35 g of phenylphosphonic dichloride. The mixture was heated to 135° C. for 1.5 hr. After cooling, the reaction solution was poured carefully into 250 ml of water and stirred for 1 hr. The water was extracted with 3×100 ml of methylene chloride. The combined organic extracts were washed with 2×100 ml of water, dried over sodium sulfate, filtered, concentrated by rotary evaporation, taken up in toluene, charcoaled, and concentrated by rotary evaporation. The crude residue was crystallized from hexane to give 1.7 g (31%) of beige analytically pure crystals, m.p. 123°-38° C. with decomposition.

Workup

  1. temperatureAfter cooling
  2. extractionThe water was extracted with 3×100 ml of methylene chloride
  3. washThe combined organic extracts were washed with 2×100 ml of water
  4. dry with materialdried over sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated by rotary evaporation
  7. concentrationconcentrated by rotary evaporation
  8. customThe crude residue was crystallized from hexane
  9. customto give 1.7 g (31%) of beige analytically pure crystals, m.p. 123°-38° C. with decomposition

Sources & evidence

ORD record
ord-b48ad2b5d8344603a25c63f76e11d005
Source dataset
uspto-grants-1987_11
Patent number
US04705853

Reaction notes

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