1,1'-Carbonyldiimidazole → Methyl 4-(3-(4-fluorophenyl)-1,2,4-oxadiazol-5-yl)bicyclo[2.2.2]octane-1-carboxylate

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Reaction Steps

To a suspension of 4-(methoxycarbonyl)bicyclo[2.2.2]octane-1-carboxylic acid (7-A) (0.906 g, 4.27 mmol) in dichloromethane (20 mL) was added 1,1′-carbonyldiimidazole (1.04 g, 6.41 mmol). The reaction turned into a clear solution instantly with evolving of gas. After the mixture was stirred at room temperature for 1 h, 4-fluorobenzamidoxime was added (1.98 g, 12.8 mmol). Stirring was continued overnight. The mixture was then concentrated and the residue was refluxed in toluene for 16 h. The mixture was concentrated and the residue was purified by column chromatography using hexane/ethyl acetate as eluent (7/1) to give methyl 4-[3-(4-fluorophenyl)-1,2,4-oxadiazol-5-yl]bicyclo[2.2.2]octane-1-carboxylate acid (7-B) as a white solid. 1H NMR (500 MHz, CDCl3) δ 1.96-1.99 (m, 6H), 2.08-2.14 (m, 6H), 3.71 (s, 3H), 7.16-7.20 (m, 2H), 8.08-8.10 (m, 2H) ppm. ESI-MS m/z (M+H) 349.2.

Provenance & Evidence