Hydrazine hydrate (1:1) → Methyl 3-(2-bromophenyl)-1H-pyrazole-5-carboxylate

HRID 1712934Notes

Reaction equation

HRID 1712934 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8](=O)[CH2:9][C:10](=O)[C:11]([O:13][CH3:14])=[O:12].O.[NH2:18][NH2:19]>CC(O)=O>[Br:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8]1[CH:9]=[C:10]([C:11]([O:13][CH3:14])=[O:12])[NH:19][N:18]=1

Participants

4

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 43119003Methyl 4-(2-bromophenyl)-2,4-dioxobutanoate

Product 1

HCID 46839989Methyl 3-(2-bromophenyl)-1H-pyrazole-5-carboxylateYield 97%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Conditions

Temperature
130 °C

Procedure

To a solution of methyl 4-(2-bromophenyl)-2,4-dioxobutanoate (540 mg, 0.0019 mol) in AcOH (4 mL) was added hydrazine monohydrate (67 mg, 0.00208 mol). The reaction mixture was allowed to stir at 130° C. overnight and then concentrated. The residue was dissolved in EtOAc, washed with aq. NaHCO3 and brine, dried over Na2SO4, filtered and concentrated to give methyl 3-(2-bromophenyl)-1H-pyrazole-5-carboxylate (0.516 g, 97%) as a white solid. LCMS: (FA) ES+ 283.2, ES-281.2.

Workup

  1. concentrationconcentrated
  2. dissolutionThe residue was dissolved in EtOAc
  3. washwashed with aq. NaHCO3 and brine
  4. dry with materialdried over Na2SO4
  5. filtrationfiltered
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-a8bc08caf8e44927817d3cda56311662
Source dataset
uspto-grants-2010_09
Patent number
US07795249B2

Reaction notes

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