2-chloro-4-fluorobenzo[d]oxazole

Synthesis

Step 2: Synthesis of 2-chloro-6-fluorobenzo[d]oxazole To a solution of 560 mg (3.31 mmol) of 4-fluorobenzo[d]oxazole-2-thione in 3.6 mL (49.65 mmol) of thionyl chloride, 60.3 μL of N,N-dimethylformamide was added slowly and dropwise at room temperature. The reaction mixture was stirred at room temperature for 2.5 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The crude product was purified by fast column chromatography on silica gel, using a gradient elution of n-heptane and ethyl acetate to afford 434 mg (76.4% yield) of 2-chloro-6-fluorobenzo[d]oxazole as a white solid. Mass spectrum (m/z): 171 ([M+H]+).

References

[1] Patent: US2009/163485, 2009, A1. Location in patent: Page/Page column 13