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

HRID 429042

Reaction equation

HRID 429042 reaction equation
[CH2:1]([N:3]1[C:7]2=[N:8][CH:9]=[C:10]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[C:11](O)=[C:6]2[CH:5]=[N:4]1)[CH3:2].P(Cl)(Cl)([Cl:20])=O>>[Cl:20][C:11]1[C:10]([C:13]([O:15][CH2:16][CH3:17])=[O:14])=[CH:9][N:8]=[C:7]2[N:3]([CH2:1][CH3:2])[N:4]=[CH:5][C:6]=12

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-carboxylateYield 87%

Procedure

1-Ethyl-4-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid, ethyl ester (15 g, 63.8 mmol) was dissolved in phosphorus oxychloride (100 mL), and the resulting solution was heated at reflux for 4 h. The remaining phosphorus oxychloride was removed via evaporation under reduced pressure. The residual light brown solid was recrystallized from EtOH-hexane to afford the title compound as a white solid (14 g, 55.3 mmol, 87%): HPLC (YMC S5 ODS 4.6×50 mm column, 4 minute gradient-0% B to 100% B, 4 mL/min flow, solvent A: 10% MeOH-90% H2O-0.2% H3PO4, solvent B: 90% MeOH-10% H2O-0.2% H3PO4) retention time 3.84 minutes showed a purity of 96%; LRMS (m/z) 254 (MH+).

Workup

  1. temperaturethe resulting solution was heated
  2. temperatureat reflux for 4 h
  3. customThe remaining phosphorus oxychloride was removed via evaporation under reduced pressure
  4. customThe residual light brown solid was recrystallized from EtOH-hexane

Sources & evidence

ORD record
ord-45368565b9544678816831a8340656ce
Source dataset
uspto-grants-2001_11
Patent number
US06316438B1

Linked notes

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