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

HRID 1453876Notes

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.F[C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][C:24]=1[N+:29]([O-:31])=[O:30].C([O-])([O-])=O.[Cs+].[Cs+]>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]([C:23]2[CH:28]=[CH:27][CH:26]=[CH:25][C:24]=2[N+:29]([O-:31])=[O:30])[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

Conditions

Temperature: 50 °C

Procedure

A solution of dimethyl 4-benzyloxy-1H-pyrazole-3,5-dicarboxylate (2.5 g, 8.63 mmol) and 2-fluoronitrobenzene (1.45 g, 10.3 mmol) in anhydrous DMF (15 mL) was treated with Cs2CO3 (3.6 g, 11 mmol) and stirred at 50° C. for 6 hours. The solvent was removed in vacuo, the residue was suspended EtOAc, and the insoluble salts were removed by filtration. The filtrate solvent was removed under reduced pressure and the residue was purified by flash column chromatography on silica gel using a gradient elution of 1:4 to 1:2 to 1:1 EtOAc:hexanes. Collection and concentration of the appropriate fractions yielded the product as an oil. 1H NMR (400 MHz, CDCl3) δ 8.21 (d, J=8.0 Hz, 1H), 7.75 (t, J=7.6 Hz, 1H), 7.68 (t, J=7.9 Hz, 1H), 7.48-7.53 (m, 3H), 7.36-7.42 (m, 3H), 5.24 (s, 2H), 3.96 (s, 3H), 3.69 (s, 3H); ES MS (M+1)=412.

Workup

customThe solvent was removed in vacuo
customthe insoluble salts were removed by filtration
customThe filtrate solvent was removed under reduced pressure
customthe residue was purified by flash column chromatography on silica gel using
washa gradient elution of 1:4 to 1:2 to 1:1 EtOAc
customCollection and concentration of the appropriate fractions

Sources & evidence

ORD record: ord-aa5d91da59df472baa6a77b2b0dc69d9
Source dataset: uspto-grants-2009_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07476666B2

Reaction notes

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