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

HRID 2268043Notes

Reaction equation

HRID 2268043 reaction equation
C(O[C:4](=O)[C:5](=[CH:11][NH:12][C:13]1[N:17]([CH2:18][CH3:19])[N:16]=[CH:15][CH:14]=1)[C:6]([O:8][CH2:9][CH3:10])=[O:7])C.O=P(Cl)(Cl)[Cl:23]>>[CH2:9]([O:8][C:6]([C:5]1[C:4]([Cl:23])=[C:14]2[CH:15]=[N:16][N:17]([CH2:18][CH3:19])[C:13]2=[N:12][CH:11]=1)=[O:7])[CH3:10]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychloride2×HCID 12845080Diethyl {[(1-ethyl-1H-pyrazol-5-yl)amino]methylene}malonate

Product 1

HCID 10491120ethyl 4-chloro-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylateYield 50%

Procedure

(1-Ethylpyrazol-5-yl-amino)methylenemalonate diethyl ester (10.0 g, 42.6 mmol) was dissolved in 50 mL POCl3. This solution was heated at reflux for 10 h before the POCl3 was removed under reduced pressure. The resulting brown residue was diluted with 5 mL EtOH and extracted with hot hexane (200 mL×3). The combined organic layers were evaporated under reduced pressure to afford the title compounds which formed light green needle shaped crystals upon standing at room temperature (5.4 g, 21.3 mmol, 50% yield). This material is identical to the one obtained in Preparation 3 (1H NMR, 13C NMR, MS, and HPLC).

Workup

  1. temperatureThis solution was heated
  2. customwas removed under reduced pressure
  3. additionThe resulting brown residue was diluted with 5 mL EtOH
  4. extractionextracted with hot hexane (200 mL×3)
  5. customThe combined organic layers were evaporated under reduced pressure

Sources & evidence

ORD record
ord-6a5c0cef9d784a1ea3ede2a9351a4f91
Source dataset
uspto-grants-2001_12
Patent number
US06326379B1

Reaction notes

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