反应详情

To a −78° C. solution of dimethylsulfoxide (4.04 g, 3.67 mL, 51.7 mmol) in methylene chloride (25 mL) was added a solution of oxalyl chloride (3.28 g, 2.26 mL, 25.9 mmol) in methylene chloride (5 mL) over two minutes. The reaction mixture was stirred for 15 minutes, and then a solution of the product of Example 38C (0.74 g, 4.31 mmol) in methylene chloride (25 mL) was added over 8 minutes. The reaction was allowed to warm to ambient temperature and quenched with water. The quenched reaction mixture was extracted with methylene chloride, and the organic layer washed with brine and concentrated. The residue was chromatographed on silica gel eluting with 25% ethyl acetate-hexane to give the title compound (0.71 g, 97%). 1H NMR (300 MHz, DMSO-d6) δ ppm 9.73 (s, 1H), 8.53 (dd, J=1.5, 4.7, 1H), 8.00 (dd, J=1.4, 8.1, 1H), 7.40 (dd, J=4.7, 8.1, 1H), 4.28 (q, J=7.0, 1H), 1.34 (d, J=7.0, 3H). MS (DCI) m/z 170 (M+H)+.

1. customquenched with water
2. customThe quenched reaction mixture
3. extractionwas extracted with methylene chloride
4. washthe organic layer washed with brine
5. concentrationconcentrated
6. customThe residue was chromatographed on silica gel eluting with 25% ethyl acetate-hexane