Hydrochloric Acid → Benzenemethanamine, 4-fluoro-N-methoxy-

A solution of 4-fluorobenzaldehyde-O-methyloxime (93.2 mmol) in dichloromethane (150 ml) was treated with sodium cyanoborohydride (9.18 g, 0.146 mol) followed by 120 ml of 2 N hydrochloric acid in methanol added dropwise over 30 minutes. After 96 h at 22° C., the solvent was evaporated under reduced pressure, the residue was slurried with water and adjusted to pH 9 with 2 N aqueous sodium hydroxide. The aqueous phase was extracted twice with dichloromethane and the combined organic extracts were washed with brine, dried (magnesium sulfate) and concentrated under reduced pressure. The residual oil was chromatographed on silica gel (elution, toluene-ethyl acetate 0-10%) and gave 5.92 g (41% yield) of the title amine as a clear oil. 1H NMR 400 MHz (CDCl3) δ (ppm): 3.49 (3H, s), 4.01 (2H, s), 5.69 (1H, broad s), 7.01 (2H, m), 7.31 (2H, m). The hydrochloride salt was obtained as a white solid: mp 170-171° C. Anal. calcd for C8H10FNO—HCl: C, 50.14; H, 5.78; N, 7.31. Found: C, 50.31; H, 5.80; N, 7.26