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

HRID 2268042Notes

Reaction equation

HRID 2268042 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].O=P(Cl)(Cl)[Cl:20]>>[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-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 POCl3 (100 mL), and the resulting solution was heated at reflux for 4 h. The remaining POCl3 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 POCl3 was removed via evaporation under reduced pressure
  4. customThe residual light brown solid was recrystallized from EtOH-hexane

Sources & evidence

ORD record
ord-a4e8171cb0274bdb9b56a4c742332334
Source dataset
uspto-grants-2001_12
Patent number
US06326379B1

Reaction notes

Loading…