Hydrochloric Acid → Ethyl 5-chloro-1-(pyridin-2-YL)-1H-pyrazole-4-carboxylate

HRID 330217Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 330217
N[C:2]1[N:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][N:8]=2)[N:5]=[CH:4][C:3]=1[C:13]([O:15][CH2:16][CH3:17])=[O:14].N([O-])=O.[Na+].[OH-].[NH4+].[ClH:24]>O>[Cl:24][C:2]1[N:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][N:8]=2)[N:5]=[CH:4][C:3]=1[C:13]([O:15][CH2:16][CH3:17])=[O:14]

Komponenten

6

Edukt 4

HCID 313Hydrochloric Acid2×HCID 14923Ammonium HydroxideHCID 742041ethyl 5-amino-1-(pyridin-2-yl)-1H-pyrazole-4-carboxylateHCID 23668193Sodium Nitrite

Produkt 1

HCID 13654084Ethyl 5-chloro-1-(pyridin-2-YL)-1H-pyrazole-4-carboxylate

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 962WaterLösungsmittel2×

Versuchsvorschrift

The product from Example 4, 21.6 g, was dissolved in 100 mL of concentrated hydrochloric acid at 0° C. To this resulting clear solution was added a solution of sodium nitrite, 7.3 g, in 10 mL of water at 0° C. during 15 minutes. The resulting suspension was stirred an additional 30 minutes then added portionwise during 10 minutes to a solution of cuprous chloride, 9.3 g, in 100 mL concentrated hydrochloric acid. The reaction was very exothermic and accompanied by rapid nitrogen evolution. The suspension was then heated on the steambath until a test for diazonium salts was negative. The contents of the flask were cooled and the pH of the suspension adjusted to 8 with ammonium hydroxide and finally diluted with 100 mL of water. The solids were removed from the reaction by filtration through Celite® and the aqueous filtrate was washed with 200 mL of methylene chloride. After separating and drying the organic solution with anhydrous sodium sulfate, 17.4 g of a light brown oil was isolated after removal of the solvent by evaporation. The crude oil was flash chromatographed on Kiesegel 60, 230-400 mesh, using 1-1 hexanes/ethyl acetate as the eluent. 14.2 g of the title compound was obtained melting at 52°-53° C.

Aufarbeitung

  1. temperatureThe contents of the flask were cooled
  2. customThe solids were removed from the reaction by filtration through Celite®
  3. washthe aqueous filtrate was washed with 200 mL of methylene chloride
  4. customAfter separating
  5. dry with materialdrying the organic solution with anhydrous sodium sulfate

Quellen und Nachweise

ORD-Eintrag
ord-0f65548f6cf64ed7aee6cf5886f77345
Quelldatensatz
uspto-grants-1990_01
Patentnummer
US04895590

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