Cesium carbonate → Dimethyl 4-benzyloxy-1-(2-bromoethyl)-1H-pyrazole-3,5-dicarboxylate

HRID 1453819Notes

Reaction equation

HRID 1453819 reaction equation
[CH2:1]([O:8][C:9]1[C:10]([C:18]([O:20][CH3:21])=[O:19])=[N:11][NH:12][C:13]=1[C:14]([O:16][CH3:17])=[O:15])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C([O-])([O-])=O.[Cs+].[Cs+].[Br:28][CH:29](Br)[CH3:30]>CN(C=O)C>[CH2:1]([O:8][C:9]1[C:13]([C:14]([O:16][CH3:17])=[O:15])=[N:12][N:11]([CH2:30][CH2:29][Br:28])[C:10]=1[C:18]([O:20][CH3:21])=[O:19])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

5

Reactant 3

HCID 10796Cesium carbonateHCID 112011,1-DibromoethaneHCID 57528491dimethyl 4-benzyloxy-1H-pyrazole-3,5-dicarboxylate

Product 1

HCID 57528492Dimethyl 4-benzyloxy-1-(2-bromoethyl)-1H-pyrazole-3,5-dicarboxylate

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of dimethyl 4-benzyloxy-1H-pyrazole-3,5-dicarboxylate (1.0 g, 3.45 mmol) in anhydrous DMF (20 mL) were added Cs2CO3 (1.35 g, 4.13 mmol) and dibromoethane (2.27 g, 12.1 mmol). The reaction mixture was stirred at room temperature for 2 hours and then filtered. The filtrate was concentrated in vacuo and the residue was purified by flash chromatography on silica gel using a 0-25% EtOAc/hexanes gradient elution. Collection and concentration of the appropriate fractions provided the title compound as a white solid. 1H NMR (400 MHz, d6-DMSO) δ 7.45-7.34 (m, 5H), 5.06 (s, 2H), 4.88 (t, J=6.4 Hz, 2H), 3.86-3.79 (m, 8H).

Workup

  1. filtrationfiltered
  2. concentrationThe filtrate was concentrated in vacuo
  3. customthe residue was purified by flash chromatography on silica gel using
  4. washa 0-25% EtOAc/hexanes gradient elution
  5. customCollection and concentration of the appropriate fractions

Sources & evidence

ORD record
ord-e12048c5340045739f9865604b71113a
Source dataset
uspto-grants-2009_01
Patent number
US07476666B2

Reaction notes

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