Acetic Anhydride → Methyl 5-methyl-1,3-oxazole-4-carboxylate
Reaction equation
[N+:1]([CH2:3][C:4]([O:6][CH3:7])=[O:5])#[C-:2].C1CCN2C(=NCCC2)CC1.[C:19](OC(=O)C)(=[O:21])[CH3:20]>C1COCC1>[CH3:20][C:19]1[O:21][CH:2]=[N:1][C:3]=1[C:4]([O:6][CH3:7])=[O:5]Participants
5
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
A stirred mixture of methyl isocyanoacetate (7.0 g, 70 mmol, 1 eq) and DBU (10.06 g, 70 mmol, 1 eq) in THF was cooled to 0° C., and a solution of acetic anhydride (7.14 g, 70 mmol, 1 eq) in THF was added dropwise over 15 min. The reaction mixture was stirred for 12 h at room temperature. The solvent was removed by Rota-vapor and water was added. The mixture was extracted with EtOAc. The crude product was purified by silica gel (230-400) column chromatography using 30% EtOAc/hexane. Yield: 6.8 g (98%). 1H NMR (400 MHz, CDCl3): δ 2.54 (s, 3H), 3.80 (s, 3H), 7.69 (s, 1H).
Workup
- customThe solvent was removed by Rota-vapor and water
- additionwas added
- extractionThe mixture was extracted with EtOAc
- customThe crude product was purified by silica gel (230-400) column chromatography
Sources & evidence
- ORD record
- ord-3181c7824b9b42e7a7fe28b102e786ac
- Source dataset
- uspto-grants-2011_08
- Patent number
- US07994171B2
Reaction notes
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