Phosphorus oxychloride → ethyl 4-chloro-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

HRID 1576812Notes

Reaction equation

HRID 1576812 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[C:7](O)=[C:8]2[CH:14]=[N:13][N:12]([CH2:15][CH3:16])[C:9]2=[N:10][CH:11]=1)=[O:5])[CH3:2].P(Cl)(Cl)([Cl:20])=O>>[CH2:1]([O:3][C:4]([C:6]1[C:7]([Cl:20])=[C:8]2[CH:14]=[N:13][N:12]([CH2:15][CH3:16])[C:9]2=[N:10][CH:11]=1)=[O:5])[CH3:2]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178469631HCID 178469631, compound

Product 1

HCID 10491120ethyl 4-chloro-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

Procedure

A mixture of 23.5 g. 1-ethyl-4-hydroxy-1H-pyrazolo[3,4-b]pyridine- 5-carboxylic acid ethyl ester (0.1 mol.) and 150 ml. of phosphorous oxychloride is refluxed for 4 hours. Subsequently, the excess phosphorous oxychloride is removed by means of vacuum distillation. As soon as the phosphorous oxychloride has been removed, the oily residue solidifies on cooling. It is treated with water and filtered under suction (24.5 g., m.p. 55°-60°). The 4-chloro compound is recrystallized from N-hexane (22.5 g. (87%), m.p. 62°).

Workup

  1. additionA mixture of 23.5 g
  2. customSubsequently, the excess phosphorous oxychloride is removed by means of vacuum distillation
  3. customAs soon as the phosphorous oxychloride has been removed
  4. temperatureon cooling
  5. additionIt is treated with water
  6. filtrationfiltered under suction (24.5 g., m.p. 55°-60°)
  7. customThe 4-chloro compound is recrystallized from N-hexane (22.5 g. (87%), m.p. 62°)

Sources & evidence

ORD record
ord-67c972f10e6a434ca8ffed0d382ee66f
Source dataset
uspto-grants-1976_09
Patent number
US03983128

Reaction notes

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