Cesium carbonate → Ethyl 5-ethyl-2-(4-nitrophenyl)-1,3-oxazole-4-carboxylate

HRID 1425059Notes

Reaction equation

[CH2:1]([C:3]1[O:7][CH:6]=[N:5][C:4]=1[C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH3:2].I[C:14]1[CH:19]=[CH:18][C:17]([N+:20]([O-:22])=[O:21])=[CH:16][CH:15]=1.CC1C=CC=CC=1P(C1C=CC=CC=1C)C1C=CC=CC=1C.C(=O)([O-])[O-].[Cs+].[Cs+]>C([O-])(=O)C.[Pd+2].C([O-])(=O)C.O.O1CCOCC1>[CH2:1]([C:3]1[O:7][C:6]([C:14]2[CH:19]=[CH:18][C:17]([N+:20]([O-:22])=[O:21])=[CH:16][CH:15]=2)=[N:5][C:4]=1[C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH3:2]

Participants

Conditions

Temperature: 100 °C

Procedure

Dioxane (30 mL) was added to ethyl 5-ethyl-1,3-oxazole-4-carboxylate (described in Armarego, Wilfred L. F.; Taguchi, Hiroyasu; Cotton, Richard G. H.; Battiston, Sandra; Leong, Lillian; Eur. J. Med. Chem. Chim. Ther.; 22; 1987; 283-292, 1.69 g, 10 mmol), 1-iodo-4-nitrobenzene (2.74 g, 11 mmol), palladium acetate (179.6 mg, 0.8 mmol), tris(2-methylphenyl)phosphine (0.49 g, 1.6 mmol) and cesium carbonate (3.25 g, 10 mmol), and the mixture was stirred at 100° C. for 13 hours. Water was added, followed by extraction with ethyl acetate and washing with brine. This was dried over anhydrous magnesium sulfate and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (elution solvent: hexane/ethyl acetate=5/1, 3/1, 2/1) to obtain 1.08 g of the title compound as a colorless solid (37%).

Workup

extractionfollowed by extraction with ethyl acetate
washwashing with brine
dry with materialThis was dried over anhydrous magnesium sulfate
concentrationconcentrated under reduced pressure
customThe residue was purified by silica gel column chromatography (elution solvent: hexane/ethyl acetate=5/1, 3/1, 2/1)

Sources & evidence

ORD record: ord-706f2c14699c4f66a29435ca7ea4fac6
Source dataset: uspto-grants-2015_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08927588B2

Reaction notes

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