Hydroxyamine hydrochloride → 3-fluoro-N'-hydroxy-4-(hydroxymethyl)benzenecarboximidamide

Participants

Reaction Steps

To a mixture of 3-fluoro-4-(hydroxymethyl)benzonitrile (3.51 g, 23.2 mmol) and hydroxylamine hydrochloride (3.23 g, 46.4 mmol) in methanol (100 mL) under nitrogen was added sodium bicarbonate (7.80 g, 93 mmol). The reaction mixture was stirred at room temperature for 5 min. and then immersed in an oil bath and heated at reflux for 2 h. HPLC analysis indicated that the starting material had been consumed. The heterogeneous mixture was filtered, the solid was washed with methanol, and the filtrate was concentrated under reduced pressure. The white solid residue was diluted with ethyl acetate (400 mL) but remained heterogeneous. The mixture was sonicated for 5 min and filtered under reduced pressure. The filtrated was washed with water (60 mL), and washed with a 10% aqueous solution of lithium chloride (60 mL), and washed with brine (60 mL). The combined aqueous layers were extracted with ethyl acetate (100 mL), and the combined organic layers were dried over anhydrous sodium sulfate. Concentration under reduced pressure afforded (Z)-3-fluoro-N′-hydroxy-4-(hydroxymethyl)benzimidamide (3.85 g, 20.9 mmol, 90% yield) as a white solid. The compound had an HPLC time=0.263 min.−Column. CHROMOLITH® SpeedROD 4.6×50 mm (4 min.); Solvent A=10% MeOH, 90% H2O, 0.1% TFA; Solvent B=90% MeOH, 10% H2O, 0.1% TFA. MS M+1=184.9. 1H NMR (500 MHz, DMSO-d6) δ ppm 4.54 (d, 2H), 5.28 (t, J=5.83 Hz, 1H), 5.86 (s, 2H), 7.40 (dd, J=11.65, 1.39 Hz, 1H), 7.44 (t, J=7.91 Hz, 1H), 7.51 (dd, J=8.05, 1.66 Hz, 1H), and 9.72 (s, 1H).

Provenance & Evidence