2: concd. NH4OH / acetone / 1.5 h 3: 2.10 g / p-toluenesulfonic acid / acetone / 1 h / Ambient temperature 4: 1.) HCl, 2b.) 4 A sieves / 1.) methanol, 10 min, 2a.) 24 h, 2b.) 6 d 5: 1.) NaCNBH3, 2.) concd. HCl / 1.) MeOH, 48 h, 2.) THF, reflux, 45 min View Scheme

2: concd. NH4OH / acetone / 1.5 h 3: 2.10 g / p-toluenesulfonic acid / acetone / 1 h / Ambient temperature 4: HCl / methanol / 0.08 h / Heating 5: NaBH4 / methanol; tetrahydrofuran / 0.5 h View Scheme

2: concd. NH4OH / acetone / 1.5 h 3: 2.10 g / p-toluenesulfonic acid / acetone / 1 h / Ambient temperature 4: NH3, HCl / methanol / 0.08 h / Heating 5: NaBH4 / methanol; tetrahydrofuran / 0.5 h 6: aq. sodium periodate / tetrahydrofuran / 24 h / Ambient temperature View Scheme

Multi-step reaction with 5 steps 2: concd. NH4OH / acetone / 1.5 h3: 2.10 g / p-toluenesulfonic acid / acetone / 1 h / Ambient temperature4: NH3, HCl / methanol / 0.08 h / Heating5: NaBH4 / methanol; tetrahydrofuran / 0.5 h  

Multi-step reaction with 2 steps 2: concd. NH4OH / acetone / 1.5 h  

Multi-step reaction with 3 steps 2: concd. NH4OH / acetone / 1.5 h3: 2.10 g / p-toluenesulfonic acid / acetone / 1 h / Ambient temperature  

Multi-step reaction with 2 steps 1: 13.10 g / pyridinium chlorochromate / CH2Cl2 / 2 h / Ambient temperature2: 4.08 g / p-toluenesulfonic acid, methyl orthoformate / toluene / 45 - 50 °C  

Multi-step reaction with 5 steps 1: p-toluenesulfonic acid / acetone / 1 h / Ambient temperature2: 1,5-diazabicyclo<4.3.0>non-5-ene (DBN) / methanol / 0.5 h3: LiAlH4 / diethyl ether / 3 h / Ambient temperature4: 13.10 g / pyridinium chlorochromate / CH2Cl2 / 2 h / Ambient temperature5: 4.08 g / p-toluenesulfonic acid, methyl orthoformate / toluene / 45 - 50 °C