1: acetic acid / 1) 0 deg C, 5 h, 2) r.t., overnight 2: conc. HCl / 6 h / Heating View Scheme

1: acetic acid / 1) 0 deg C, 5 h, 2) r.t., overnight 2: conc. HCl / 6 h / Heating 3: 80 percent / conc. H2SO4 / 4 h / Heating 4: 88.9 percent / NaBH4 / ethanol / 1) 0 deg C, 2 h, 2) r.t., overnight View Scheme