反应详情

A solution of 6-(4-fluorophenyl)-imidazo[2,1-b]oxazole (2.5 g, 0.0124 mol) in acetic anhydride (60 ml) was heated to 140° C. and then treated with concentrated sulfuric acid (5 drops). After 15 minute at that temperature, HPLC showed clean conversion and the reaction mixture was quenched by the addition of ice cold water (150 ml). The mixture was extracted with ethyl acetate (3×150 ml). The combined extracts were washed with a saturated aqueous sodium chloride solution (300 ml), dried over magnesium sulfate and concentrated in vacuo as a brown solid. Trituration from a mixture of hexanes/ethyl acetate (1:1) provided 2.2 g (72.6%) of a pale yellow solid. M.p.=173° C.; 300 MHz 1H NMR (DMSO-d6) δ 8.25-8.19 (m, 2H), 7.75-7.68 (m, 2H), 7.35-7.25 (m, 2H), 2.15 (s, 3H). LCMS: 245 [M+H].

1. customconversion and the reaction mixture was quenched by the addition of ice cold water (150 ml)
2. extractionThe mixture was extracted with ethyl acetate (3×150 ml)
3. washThe combined extracts were washed with a saturated aqueous sodium chloride solution (300 ml)
4. dry with materialdried over magnesium sulfate
5. concentrationconcentrated in vacuo as a brown solid
6. additionTrituration from a mixture of hexanes/ethyl acetate (1:1)