Synthesis
The general procedure for the synthesis of 5-fluorobenzo[d]oxazol-2(3H)-ones from 2-amino-4-fluorophenol and N,N'-carbonyldiimidazole (CDI) is as follows: 2-amino-4-fluorophenol (1 eq.) was dissolved with N,N'-carbonyldiimidazole (1.2 eq.) in DMF under the protection of nitrogen, and the reaction was stirred for 5 hr at 80 °C. After completion of the reaction, the mixture was cooled to room temperature and the reaction was quenched by the addition of water. The reaction mixture was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography to afford the target compounds 5-fluorobenzo[d]oxazol-2(3H)-one (4a-d).
References
[1] European Journal of Medicinal Chemistry, 2017, vol. 138, p. 199 - 211
[2] Patent: WO2005/18529, 2005, A2. Location in patent: Page/Page column 62
[3] Journal of Medicinal Chemistry, 2015, vol. 58, # 23, p. 9258 - 9272
[4] Organic and Biomolecular Chemistry, 2017, vol. 15, # 19, p. 4058 - 4063
