Phosphorus oxychloride → 1-ethyl-4-chloro-1H-pyrazolo[3,4-b]quinoline

HRID 1456014Notes

Reaction equation

HRID 1456014 reaction equation
[CH2:1]([N:3]1[C:7]([NH:8][C:9]2[C:10](=[CH:14][CH:15]=[CH:16][CH:17]=2)[C:11](O)=O)=[CH:6][CH:5]=[N:4]1)[CH3:2].O=P(Cl)(Cl)[Cl:20]>>[CH2:1]([N:3]1[C:7]2=[N:8][C:9]3[C:10]([C:11]([Cl:20])=[C:6]2[CH:5]=[N:4]1)=[CH:14][CH:15]=[CH:16][CH:17]=3)[CH3:2]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 154274682-((1-Ethyl-1H-pyrazol-5-yl)amino)benzoic acid

Product 1

HCID 158169081-ethyl-4-chloro-1H-pyrazolo[3,4-b]quinolineYield 68.3%

Procedure

A mixture of N-(1-ethylpyrazol-5-yl)anthranilic acid (278 g, 1.2 mol) and POCl3 (550 g, 3.6 mol) was refluxed for 3 hours. The reaction mixture was cooled and then was poured into ice/water (3-4 L) . A solid formed which was collected by filtration and washed with water. The filtrate was extracted with CH2Cl2 (1 L) and the CH2Cl2 layer was evaporated to about 50 ml and both this solution and the previously isolated solid were purified by column chromatography on silica gel eluting with CH2Cl2 to afford 190 g (68%) of 1-ethyl-4-chloro-1H-pyrazolo[3,4-b]quinoline.

Workup

  1. temperaturewas refluxed for 3 hours
  2. temperatureThe reaction mixture was cooled
  3. customA solid formed which
  4. filtrationwas collected by filtration
  5. washwashed with water
  6. extractionThe filtrate was extracted with CH2Cl2 (1 L)
  7. customthe CH2Cl2 layer was evaporated to about 50 ml and both this solution
  8. customthe previously isolated solid were purified by column chromatography on silica gel eluting with CH2Cl2

Sources & evidence

ORD record
ord-15e7fcc8ab484cfe81800c675a2327d2
Source dataset
uspto-grants-1998_12
Patent number
US05843956

Reaction notes

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