Phosphorus oxychloride → Ethyl 4-chloro-1-ethyl-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

HRID 1902608Notes

Reaction equation

HRID 1902608 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[C:7](O)=[C:8]2[CH:15]=[N:14][N:13]([CH2:16][CH3:17])[C:9]2=[N:10][C:11]=1[CH3:12])=[O:5])[CH3:2].P(Cl)(Cl)([Cl:21])=O>>[CH2:1]([O:3][C:4]([C:6]1[C:7]([Cl:21])=[C:8]2[CH:15]=[N:14][N:13]([CH2:16][CH3:17])[C:9]2=[N:10][C:11]=1[CH3:12])=[O:5])[CH3:2]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178469191Ethyl 1-ethyl-4-hydroxy-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

Product 1

HCID 13059311Ethyl 4-chloro-1-ethyl-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

Procedure

A mixture of 49.1 g of 1-ethyl-6-methyl-4-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester (0.197 mole) and 250 ml of phosphorus oxychloride is refluxed for 4 hours. Then the excess phosphorus oxychloride is removed by vacuum distillation and the residue is treated with water. The 4-chloro compound (42 g) is filtered under suction and recrystallized from n-hexane, mp 54°-56° C.

Workup

  1. temperatureis refluxed for 4 hours
  2. customThen the excess phosphorus oxychloride is removed by vacuum distillation
  3. additionthe residue is treated with water
  4. filtrationThe 4-chloro compound (42 g) is filtered under suction
  5. customrecrystallized from n-hexane, mp 54°-56° C.

Sources & evidence

ORD record
ord-34b5522be43e4eeda03b914277cd2eae
Source dataset
uspto-grants-1982_12
Patent number
US04364948

Reaction notes

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