Hydrazine hydrate (1:1) → 5-Phenyl-1H-pyrazol-4-amine

HRID 1256238Notes

Reaction equation

HRID 1256238 reaction equation
C[N:2](C)[CH:3]=[C:4]([N:13]1C(=O)C2C(=CC=CC=2)C1=O)[C:5](=O)[C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.O.[NH2:26]N>C(O)C>[C:6]1([C:5]2[NH:26][N:2]=[CH:3][C:4]=2[NH2:13])[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1

Participants

4

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 66721049HCID 66721049, compound

Product 1

HCID 123271055-Phenyl-1H-pyrazol-4-amine

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A 250 ml round-bottomed flask is charged at RT with 20.5 g of a mixture of the E and Z isomers of 2-[1-(dimethylamino)-3-oxo-3-phenylprop-1-en-2-yl]-1H-isoindole-1,3(2H)dione in 75 ml of ethanol. 7.8 ml of hydrazine hydrate are added. The suspension is stirred at RT for 1 h 30 min and then heated to reflux. After 1 h 30 min of heating, a thickening of the mixture may be observed, and it takes on a yellow colour. The suspension is filtered off hot with suction on a frit and the precipitate is washed with ethanol. The filtrate is concentrated under RP. The product is purified by flash chromatography on silica gel (15-40 μm), eluting with DCM and with a DCM/methanol mixture (95/5 by vol.), to give 9.45 g of 5-phenyl-1H-pyrazol-4-amine (brown solid). LC-MS-DAD-ELSD: 163 (+)=(M+H)(+).

Workup

  1. temperatureheated to reflux
  2. temperatureAfter 1 h 30 min of heating
  3. filtrationThe suspension is filtered off hot with suction on a frit
  4. washthe precipitate is washed with ethanol
  5. concentrationThe filtrate is concentrated under RP
  6. customThe product is purified by flash chromatography on silica gel (15-40 μm)
  7. washeluting with DCM and with a DCM/methanol mixture (95/5 by vol.)

Sources & evidence

ORD record
ord-b3f8470cc06d4340be509dcd1aaffcda
Source dataset
uspto-grants-2013_06
Patent number
US08461175B2

Reaction notes

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