Triphosgene → 8-chloro-7-(4-chlorophenyl)-2H-[1,2,4]triazolo[4,3-b]pyridazin-3-one

HRID 2224280Notes

Reaction equation

HRID 2224280 reaction equation
Cl[C:2](Cl)([O:4]C(=O)OC(Cl)(Cl)Cl)Cl.[Cl:13][C:14]1[C:19]([C:20]2[CH:25]=[CH:24][C:23]([Cl:26])=[CH:22][CH:21]=2)=[CH:18][N:17]=[N:16][C:15]=1[NH:27][NH2:28].ClC1N=NC=C(C2C=CC(Cl)=CC=2)C=1NN>C1COCC1>[Cl:13][C:14]1[C:15]2[N:16]([C:2](=[O:4])[NH:28][N:27]=2)[N:17]=[CH:18][C:19]=1[C:20]1[CH:21]=[CH:22][C:23]([Cl:26])=[CH:24][CH:25]=1

Participants

5

Reactant 3

HCID 94429TriphosgeneHCID 597166211-(4-Chloro-5-(4-chlorophenyl)pyridazin-3-yl)hydrazineHCID 865990071-(3-Chloro-5-(4-chlorophenyl)pyridazin-4-yl)hydrazine

Product 1

HCID 597166868-chloro-7-(4-chlorophenyl)-2H-[1,2,4]triazolo[4,3-b]pyridazin-3-one

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A stirring solution of triphosgene (17.5 g, 59.0 mmol) in THF (150 mL) was cooled to 0° C. under argon and a mixture of 1-(4-chloro-5-(4-chlorophenyl)pyridazin-3-yl)hydrazine and 1-(3-chloro-5-(4-chlorophenyl)pyridazin-4-yl)hydrazine, as prepared in Example 361E, (3.0 g gross) was added over 3 min. The reaction mixture was then allowed to warm to RT gradually and then was stirred for 16 h. The solvent was removed under vacuum to reduce the reaction mixture to half its original volume, and the resulting suspension was cooled in an ice bath. Ice water (300 mL) was added, followed by stirring for 30 min. The product was collected by filtration and washed with 0.5 N aqueous HCl (20 mL×2), then H2O (20 mL×2). After drying under vacuum at room temperature for 16 h, the title compound, 8-chloro-7-(4-chlorophenyl)-[1,2,4]triazolo[4,3-b]pyridazin-3(2H)-one, (2.1 g) was obtained as a yellow solid. MS [M+H]+ 281; HPLC retention time=2.71 min.

Workup

  1. customas prepared in Example 361E, (3.0 g gross)
  2. additionwas added over 3 min
  3. customThe solvent was removed under vacuum
  4. temperaturethe resulting suspension was cooled in an ice bath
  5. additionIce water (300 mL) was added
  6. stirringby stirring for 30 min
  7. filtrationThe product was collected by filtration
  8. washwashed with 0.5 N aqueous HCl (20 mL×2)
  9. customAfter drying under vacuum at room temperature for 16 h

Sources & evidence

ORD record
ord-3253bd9d7e224a468eda322df1c8c30e
Source dataset
uspto-grants-2008_05
Patent number
US07378418B2

Reaction notes

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