Phosphorus oxychloride → Ethyl 4-chloropyrazolo[1,5-A]quinoxaline-3-carboxylate

HRID 65771Notes

Reaction equation

HRID 65771 reaction equation
O[C:2]1[C:3]2[N:4]([N:12]=[CH:13][C:14]=2[C:15]([O:17][CH2:18][CH3:19])=[O:16])[C:5]2[C:10]([N:11]=1)=[CH:9][CH:8]=[CH:7][CH:6]=2.P(Cl)(Cl)([Cl:22])=O>>[Cl:22][C:2]1[C:3]2[N:4]([N:12]=[CH:13][C:14]=2[C:15]([O:17][CH2:18][CH3:19])=[O:16])[C:5]2[C:10]([N:11]=1)=[CH:9][CH:8]=[CH:7][CH:6]=2

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178469945HCID 178469945, compound

Product 1

HCID 54256020Ethyl 4-chloropyrazolo[1,5-A]quinoxaline-3-carboxylate

Procedure

50 g. of the product of Example 1, part b in 200 ml. of phosphorus oxychloride are refluxed for 3 hours. After distilling off the excess phosphorus oxychloride, 4-chloropyrazolo[1,5-a]quinoxaline-3-carboxylic acid, ethyl ester crystallizes. The distillation residue is stirred shortly with ice water and then the crude product is filtered off. The crude product is dried briefly over potassium hydroxide and recrystallized from acetone. The pure product is obtained as white needles; yield 39.5 g., m.p. 105°-106°.

Workup

  1. distillationAfter distilling off the excess phosphorus oxychloride, 4-chloropyrazolo[1,5-a]quinoxaline-3-carboxylic acid, ethyl ester
  2. customcrystallizes
  3. filtrationthe crude product is filtered off
  4. dry with materialThe crude product is dried briefly over potassium hydroxide
  5. customrecrystallized from acetone
  6. customThe pure product is obtained as white needles

Sources & evidence

ORD record
ord-195fabc7e534421e9f19dad98dea3461
Source dataset
uspto-grants-1978_12
Patent number
US04128716

Reaction notes

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