反应详情

To a solution of 2-chloro-6-fluorobenzoic acid (2.14 g, 12.3 mmol), CH2Cl2 (50 ml), and DMF (2 drops) at room temperature under N2 was added oxalyl chloride (9.2 ml, 18.4 mmol) dropwise. The mixture was stirred for 3 h and the volatiles were removed under reduced pressure to give the crude acid chloride. The crude acid chloride and methyl isocyanoacetate (1.23 g, 12.3 mmol) were dissolved in THF (20 ml) at room temperature under N2 and Et3N (6.8 ml, 49.2 mmol) was added dropwise over a period of 30 minutes. The reaction was allowed to stir for 22 h followed by dilution with Et2O, extraction with H2O, 1N HCl, H2O, brine, dried (MgSO4), filtered, and concentrated. Column chromatography (silica gel, hexanes/Et2O gradient) gave 4-methoxycarbonyl-5-(2-chloro-6-fluorophenyl)oxazole (0.74 g, 24%).

1. customthe volatiles were removed under reduced pressure
2. customto give the crude acid chloride
3. stirringto stir for 22 h
4. extractionfollowed by dilution with Et2O, extraction with H2O, 1N HCl, H2O, brine
5. dry with materialdried (MgSO4)
6. filtrationfiltered
7. concentrationconcentrated