Sulfuric Acid → Methyl [5-methyl-2-(4-methylphenyl)-1,3-oxazol-4-YL]acetate

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Reaction Steps

The intermediate prepared in Example 8 (280 g, 1.06 mol) was dissolved in acetic anhydride (650 mL) followed by slow addition of conc. H2SO4 (60 ml). The pot temperature reached 80° C. The reaction was then held at 85° C. for 1 hour, cooled, and the acetic anhydride removed in vacuo. The residue was poured into ice water (2 L) and extracted with EtOAc (4 L total). The organic layer was then stirred with 1 N NaOH (500 mL) for 1 hour, separated, then dried with MgSO4 and concentrated to afford the title ester as a clear oil (223 g, 87%), which slowly solidified to a white solid.

Provenance & Evidence