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

HRID 1458730Notes

Reaction equation

HRID 1458730 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) is refluxed for 3 hours. The reaction mixture is cooled and then poured into ice/water (3-4 L). A solid forms which is collected by filtration and washed with water. The filtrate is extracted with CH2Cl2 (1 L) and the CH2Cl2 layer is evaporated to about 50 ml, and both this solution and the previously isolated solid are purified by colunm 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. temperatureis refluxed for 3 hours
  2. temperatureThe reaction mixture is cooled
  3. filtrationA solid forms which is collected by filtration
  4. washwashed with water
  5. extractionThe filtrate is extracted with CH2Cl2 (1 L)
  6. customthe CH2Cl2 layer is evaporated to about 50 ml
  7. customboth this solution and the previously isolated solid are purified by colunm chromatography on silica gel eluting with CH2Cl2

Sources & evidence

ORD record
ord-449bd1fdb63a4ebdb344a8995b5b931c
Source dataset
uspto-grants-1998_12
Patent number
US05852035

Reaction notes

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