Sodium Hydroxide → 3-(2-Chloropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine

HRID 703987Notes

Reaction equation

HRID 703987 reaction equation
O=[C:2]1[CH:7]=[C:6]([C:8]2[C:9]([C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=3)=[N:10][N:11]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=23)[CH:5]=[CH:4][NH:3]1.P(Cl)(Cl)([Cl:25])=O.[OH-].[Na+]>>[Cl:25][C:2]1[CH:7]=[C:6]([C:8]2[C:9]([C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=3)=[N:10][N:11]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=23)[CH:5]=[CH:4][N:3]=1

Participants

4

Reactant 3

HCID 14798Sodium HydroxideHCID 24813Phosphorus oxychlorideHCID 151581123-(2-Oxo-1,2-dihydropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine

Product 1

HCID 151581423-(2-Chloropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine

Conditions

Temperature
70 °C

Procedure

A mixture of 3-(2-oxo-1,2-dihydropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine (0.6 g) and phosphorus oxychloride (1.8 ml) was stirred for 6 hours at 70° C. After cooling, the reaction mixture was poured onto ice (30 g) and made alkaline with 24% aqueous solution of sodium hydroxide (pH=10) and extracted with chloroform (18 ml). The combined extract was washed with water and sodium chloride aqueous solution and dried over magnesium sulfate. The solvent was removed in vacuo and the residue was chromatographed on silica gel (12 g) with chloroform as an eluent. The fractions containing the object compound were combined and evaporated in vacuo and recrystallized from a mixture of ethyl acetate and diisopropyl ether to give 3-(2-chloropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine (0.21 g).

Workup

  1. temperatureAfter cooling
  2. additionthe reaction mixture was poured onto ice (30 g)
  3. extractionextracted with chloroform (18 ml)
  4. extractionThe combined extract
  5. washwas washed with water and sodium chloride aqueous solution
  6. dry with materialdried over magnesium sulfate
  7. customThe solvent was removed in vacuo
  8. customthe residue was chromatographed on silica gel (12 g) with chloroform as an eluent
  9. additionThe fractions containing the object compound
  10. customevaporated in vacuo
  11. customrecrystallized from a mixture of ethyl acetate and diisopropyl ether

Sources & evidence

ORD record
ord-011015334c7144bda4d023bef761ec2e
Source dataset
uspto-grants-1991_01
Patent number
US04985444

Reaction notes

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