Hydrochloric Acid → 3-Methyl-4-(2-pyridylazo)-1-(p-sulfophenyl)-2-pyrazolin-5-one

HRID 26119

Reaction equation

HRID 26119 reaction equation
Br[C:2]1(Br)[C:6](=[O:7])[N:5]([C:8]2[CH:13]=[CH:12][C:11]([S:14]([OH:17])(=[O:16])=[O:15])=[CH:10][CH:9]=2)[N:4]=[C:3]1[CH3:18].[NH:20]([C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][N:23]=1)[NH2:21].Cl>O>[CH3:18][C:3]1[CH:2]([N:21]=[N:20][C:22]2[CH:27]=[CH:26][CH:25]=[CH:24][N:23]=2)[C:6](=[O:7])[N:5]([C:8]2[CH:13]=[CH:12][C:11]([S:14]([OH:17])(=[O:16])=[O:15])=[CH:10][CH:9]=2)[N:4]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 786452-HydrazinopyridineHCID 203940744,4-Dibromo-3-methyl-1-(4-sulfophenyl)-2-pyrazolin-5-one

Product 1

HCID 203940703-Methyl-4-(2-pyridylazo)-1-(p-sulfophenyl)-2-pyrazolin-5-one

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

41.0 g (0.10 mole) of 4,4-dibromo-3-methyl-1-(4-sulfophenyl)-2-pyrazolin-5-one, which can be prepared according to the method of Machiele, U.S. Pat. No. 3,952,009 (Example 1), and 16.0 g (0.15 mole) of 2-hydrazinopyridine were combined in 180 ml of water. The mixture was heated on the steam bath a total of six hours. After a few minutes of heating, the solution goes to a very thick slurry. The mixture was cooled somewhat, 10 ml of concentrated HCl were added, and the orange solid was isolated by suction filtration. After washing once with tetrahydrofuran, twice with ether, and drying, the yield of dye was 17.8 g (50 percent).

Workup

  1. temperatureThe mixture was heated on the steam bath a total of six hours
  2. temperatureAfter a few minutes of heating
  3. temperatureThe mixture was cooled somewhat
  4. customthe orange solid was isolated by suction filtration
  5. washAfter washing once with tetrahydrofuran, twice with ether
  6. customdrying

Sources & evidence

ORD record
ord-3e22b618bac643c9a551629a270f7fb7
Source dataset
uspto-grants-1979_04
Patent number
US04148641

Linked notes

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