sodium hydroxide; sulfuric acid; bis-(2-hydroxy-ethyl)-amine in diethyl ether; water soln. diethanolamine in isopropanol was added to protected boronic acid at 0°C and stirred for 3 h, Et2O was added, ppt. was filtered off, mixt. aq. H2SO4 and Et2O was added and stirred, Et2O soln. was separated, washed with water, and evapd.; residue was refluxed with 3 M NaOH for 3 h, cooled to 0°C and acidified with conc. HCl, ppt. was filtered off, washed with water, and dried; elem. anal.;

sodium hydroxide 3 h; Heating;

1: 67 percent / PdCl2(dppf); potassium acetate / dimethylsulfoxide / 4 h / 80 °C 2: 82 percent / aq. NaOH / 3 h / Heating View Scheme

hydrogenchloride 24 h; Heating / reflux;