反应详情

To a solution of crude 1-benzooxazol-5-yl-cyclopropanecarboxylic acid methyl ester (2.9 g) in EtSH (30 mL) was added AlCl3 (5.3 g, 40.1 mmol) in portions at 0° C. The reaction mixture was stirred for 18 hours at room temperature. Water (20 mL) was added dropwise at 0° C. The resulting mixture was extracted with EtOAc (100 mL×3). The combined organic layers were dried over anhydrous Na2SO4 and evaporated under vacuum to give the crude product, which was purified by column chromatography on silica gel (petroleum ether/EtOAc 1:2) to give 1-(benzo[d]oxazol-5-yl)cyclopropanecarboxylic acid (280 mg, two steps: 11%). 1H NMR (DMSO, 400 MHz) δ 12.25 (brs, 1 H), 8.71 (s, 1 H), 7.70-7.64 (m, 2 H), 7.40 (dd, J=1.6, 8.4 Hz, 1 H), 1.49-1.46 (m, 2 H), 1.21-1.18 (m, 2 H). MS (ESI) m/e (M+H+) 204.4.

1. extractionThe resulting mixture was extracted with EtOAc (100 mL×3)
2. dry with materialThe combined organic layers were dried over anhydrous Na2SO4
3. customevaporated under vacuum
4. customto give the crude product, which
5. customwas purified by column chromatography on silica gel (petroleum ether/EtOAc 1:2)