1,4-Dioxane hydrochloride → 3-Hydroxy-1-oxo-1-phenylpropan-2-aminium chloride

tert-butyl 3-hydroxy-1-oxo-1-phenylpropan-2-ylcarbamate (19) (270 mg, 1.0 mmol, 1.0 equiv) was added to a 25 mL RBF and a 4.0 N HCl-Dioxane solution (7.5 mL, 30.0 mmol, 30.0 equiv.) was added. The solution was stirred at rt. for 25 min, and 5 mL dioxane was evaporated with a steady stream of N2 (g). Next, Et2O (10 mL) was added to the reaction flask and a white precipitate formed. The soln was stirred for 10 min and filtered with a Buchner funnel. The precipitate was dried under vacuum to give 170 mg (86%) of 6 as a white solid. mp=160-162° C.; 1H NMR (500 MHz, DMSO) δ 8.94 (s, 3H, CH—NH3) 8.07 (d, J=7.0 Hz, 2H, Ph-H), 7.73 (t, J=7.0 Hz, 1H, Ph-H), 7.59 (t, J=7.5 Hz, 2H, Ph-H), 5.53 (br s, 1H, CH2—OH), 5.19 (s, 1H, +NH3—CH), 3.94 (d, J=11.5 Hz, 1H, CH—CH2), 3.85 (d, J=11.5 Hz, 1H, CH—CH2); 13C NMR (125 MHz, DMSO) δ 194.5, 134.3, 133.7, 129.1, 128.8, 60.6, 57.6; LRMS (ESI-MS m/z): Mass calcd for C9H12NO2 [M]+, 166.20. Found 166. Anal. calcd for C9H12ClNO2: C, 53.61; H, 6.00; N, 6.95. Found: C, 53.26; H, 6.13; N, 6.96.