13451-78-0

2-Amino-4-fluorophenol (10 g, 78.8 mmol), carbon disulfide (35 mL) and potassium hydroxide (5.3 g, 94.6 mmol) were mixed in ethanol (200 mL) and heated to reflux the reaction overnight. Upon completion of the reaction, the reaction mixture was concentrated to dryness and subsequently diluted with water. The diluted solution was neutralized with 1 M hydrochloric acid solution and then extracted several times with ethyl acetate. The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and finally concentrated under vacuum to give 5-fluorobenzo[d]oxazole-2-thiol 9.3 g in 70% yield. The product was identified by 1H NMR (300MHz, DMSO-d6): δ7.51 (ddd, J=8.8,4.2,0.6Hz, 1H), 7.15-7.04 (m, 2H), 3.31 (brs, 1H). lC-MS (m/z): 170.2.

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