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

HRID 429043Notes

Reaction equation

HRID 429043 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.P(Cl)(Cl)([Cl:23])=O>>[Cl:23][C:4]1[C:5]([C:6]([O:8][CH2:9][CH3:10])=[O:7])=[CH:11][N:12]=[C:13]2[N:17]([CH2:18][CH3:19])[N:16]=[CH:15][C:14]=12

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-ylamino)methylenemalonate diethyl ester (10.0 g, 42.6 mmol) was dissolved in phosphorus oxychloride (50 mL). This solution was heated at reflux for 10 h before the phosphorus oxychloride was removed via evaporation under reduced pressure. The resulting brown residue was diluted with EtOH (5 mL) and extracted with hot hexane (200 mL×3). The combined organic layers were evaporated under reduced pressure to afford the title compound as an oil 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, MS, and HPLC).

Workup

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

Sources & evidence

ORD record
ord-d8b5e2a91eee41d6b41ec7622938532a
Source dataset
uspto-grants-2001_11
Patent number
US06316438B1

Reaction notes

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