反应详情

To a solution of 2-(3-chloro-benzoylamino)-3-hydroxy-propionic acid methyl ester (7.2 g, 29.6 mmol) in CH2Cl2 at −20° C. was added dropwise De-oxofluor (7.2 g, 32.6 mmol). After stirring at this temperature for 30 min, BrCCl3 (3.6 g, 18.1 mmol) was added dropwise followed by DBU (2.79 g, 18.1 mmol). The mixture was then stirred at 2-3° C. for 8 h ad then quenched with saturated NaHCO3 followed by extraction with ethyl acetate. The organic extract as then washed with brine and dried over Na2SO4 (anhydrous). Purification was performed by flash column chromatography on silica gel using ethyl acetate in hexanes as eluant to afford 2-(3-chloro-phenyl)-oxazole-4-carboxylic acid methyl ester (4.1 g, 59%) as a yellow solid. 1H NMR (CDCl3) d (ppm): 8.30 (s, 1 H), 8.12 (d, 1 H), 7.98 (dd, 1 H), 7.45 (m, 2 H), 3.96 (s, 3 H).

1. stirringThe mixture was then stirred at 2-3° C. for 8 h ad
2. customthen quenched with saturated NaHCO3
3. extractionfollowed by extraction with ethyl acetate
4. extractionThe organic extract
5. washas then washed with brine
6. dry with materialdried over Na2SO4 (anhydrous)
7. customPurification