Acetic Anhydride → 1-[6-(2-Chlorophenyl)imidazo[2,1-b][1,3]oxazol-5-yl]ethanone

Participants

Reaction Conditions

Reaction Steps

To a mixture of 6-(2-chlorophenyl)-imidazo[2,1-b]oxazole (1.0 g, 4.57 mmol) and acetic anhydride (23 ml) is added 3 drops of concentrated sulfuric acid. The reaction mixture is heated at 135° C. for 1 hour. The reaction mixture is then poured onto 50 ml of ice, and diluted with 100 ml of water and the resulting mixture is extracted three times with 75 ml each of ethyl acetate. The combined extracts are dried with magnesium sulfate, filtered and concentrated in vacuo, to give a brown oil. The product is purified by flash chromatography on silica gel (hexane/ethyl acetate 3:1), yielding 994 mg of an off-white solid (83%). M.p.=121-122° C.; 300 MHz 1H NMR (CDCl3) δ: 8.02 (d, J=1.6 Hz, 1H), 7.56-7.38 (m, 5H), 2.05 (s, 3H). LCMS: 261 [M+H]; calc. for C13H9ClN2O2: C, 59.84; H, 3.48; N, 10.74; found. C, 60.18; H, 3.16; N, 10.61.

Provenance & Evidence