1: NaClO2, NH2SO3H 3: selective mono-demethylation 4: K2CO3 / dimethylformamide 5: aq. Na2S2O4 6: K2CO3 / acetone / 6 h / Heating 7: aq. KOH / ethanol / 10 h / 25 °C 8: PPE / CHCl3 / 36 h / 25 °C 9: aq. KOH / ethanol / 8 h / 25 °C 11: PCC / CH2Cl2 / 15 h / 25 °C 12: 82 percent / K2CO3 / methanol / 36 h / 25 °C 13: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 14: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 15: NaBH4 View Scheme

2: selective mono-demethylation 3: K2CO3 / dimethylformamide 4: aq. Na2S2O4 5: K2CO3 / acetone / 6 h / Heating 6: aq. KOH / ethanol / 10 h / 25 °C 7: PPE / CHCl3 / 36 h / 25 °C 8: aq. KOH / ethanol / 8 h / 25 °C 10: PCC / CH2Cl2 / 15 h / 25 °C 11: 82 percent / K2CO3 / methanol / 36 h / 25 °C 12: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 13: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 14: NaBH4 View Scheme

1: K2CO3 / dimethylformamide 2: aq. Na2S2O4 3: K2CO3 / acetone / 6 h / Heating 4: aq. KOH / ethanol / 10 h / 25 °C 5: PPE / CHCl3 / 36 h / 25 °C 6: aq. KOH / ethanol / 8 h / 25 °C 8: PCC / CH2Cl2 / 15 h / 25 °C 9: 82 percent / K2CO3 / methanol / 36 h / 25 °C 10: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 11: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 12: NaBH4 View Scheme

1: selective mono-demethylation 2: K2CO3 / dimethylformamide 3: aq. Na2S2O4 4: K2CO3 / acetone / 6 h / Heating 5: aq. KOH / ethanol / 10 h / 25 °C 6: PPE / CHCl3 / 36 h / 25 °C 7: aq. KOH / ethanol / 8 h / 25 °C 9: PCC / CH2Cl2 / 15 h / 25 °C 10: 82 percent / K2CO3 / methanol / 36 h / 25 °C 11: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 12: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 13: NaBH4 View Scheme

1: 75 percent / NaH / tetrahydrofuran / 16 h / Heating 2: 95 percent / C5H5NHBr3, AcOH / 1 h / 25 °C 3: 65 percent / DBU / CH2Cl2 / 10 h / 25 °C 4: 85 percent / K2CO3 / acetone / 10 h / Heating 5: 74 percent / LDA / tetrahydrofuran / 1.5 h / -78 °C 6: 80 percent / NaBH4, K2CO3 / methanol / 0.5 h / 25 °C 7: 95 percent / (NH4)2Ce(NO3)6 / acetonitrile; H2O / 0.25 h / 25 °C 8: K2CO3 / dimethylformamide 9: aq. Na2S2O4 10: K2CO3 / acetone / 6 h / Heating 11: aq. KOH / ethanol / 10 h / 25 °C 12: PPE / CHCl3 / 36 h / 25 °C 13: aq. KOH / ethanol / 8 h / 25 °C 15: PCC / CH2Cl2 / 15 h / 25 °C 16: 82 percent / K2CO3 / methanol / 36 h / 25 °C 17: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 18: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 19: NaBH4 View Scheme

1: PPE / CHCl3 / 30 h / 25 °C 2: 75 percent / NaH / tetrahydrofuran / 16 h / Heating 3: 95 percent / C5H5NHBr3, AcOH / 1 h / 25 °C 4: 65 percent / DBU / CH2Cl2 / 10 h / 25 °C 5: 85 percent / K2CO3 / acetone / 10 h / Heating 6: 74 percent / LDA / tetrahydrofuran / 1.5 h / -78 °C 7: 80 percent / NaBH4, K2CO3 / methanol / 0.5 h / 25 °C 8: 95 percent / (NH4)2Ce(NO3)6 / acetonitrile; H2O / 0.25 h / 25 °C 9: K2CO3 / dimethylformamide 10: aq. Na2S2O4 11: K2CO3 / acetone / 6 h / Heating 12: aq. KOH / ethanol / 10 h / 25 °C 13: PPE / CHCl3 / 36 h / 25 °C 14: aq. KOH / ethanol / 8 h / 25 °C 16: PCC / CH2Cl2 / 15 h / 25 °C 17: 82 percent / K2CO3 / methanol / 36 h / 25 °C 18: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 19: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 20: NaBH4 View Scheme

1: KOH / ethanol / 8 h / 23 °C 2: PPE / CHCl3 / 30 h / 25 °C 3: 75 percent / NaH / tetrahydrofuran / 16 h / Heating 4: 95 percent / C5H5NHBr3, AcOH / 1 h / 25 °C 5: 65 percent / DBU / CH2Cl2 / 10 h / 25 °C 6: 85 percent / K2CO3 / acetone / 10 h / Heating 7: 74 percent / LDA / tetrahydrofuran / 1.5 h / -78 °C 8: 80 percent / NaBH4, K2CO3 / methanol / 0.5 h / 25 °C 9: 95 percent / (NH4)2Ce(NO3)6 / acetonitrile; H2O / 0.25 h / 25 °C 10: K2CO3 / dimethylformamide 11: aq. Na2S2O4 12: K2CO3 / acetone / 6 h / Heating 13: aq. KOH / ethanol / 10 h / 25 °C 14: PPE / CHCl3 / 36 h / 25 °C 15: aq. KOH / ethanol / 8 h / 25 °C 17: PCC / CH2Cl2 / 15 h / 25 °C 18: 82 percent / K2CO3 / methanol / 36 h / 25 °C 19: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 20: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 21: NaBH4 View Scheme

1: 85 percent / K2CO3 / acetone / 10 h / Heating 2: 74 percent / LDA / tetrahydrofuran / 1.5 h / -78 °C 3: 80 percent / NaBH4, K2CO3 / methanol / 0.5 h / 25 °C 4: 95 percent / (NH4)2Ce(NO3)6 / acetonitrile; H2O / 0.25 h / 25 °C 5: K2CO3 / dimethylformamide 6: aq. Na2S2O4 7: K2CO3 / acetone / 6 h / Heating 8: aq. KOH / ethanol / 10 h / 25 °C 9: PPE / CHCl3 / 36 h / 25 °C 10: aq. KOH / ethanol / 8 h / 25 °C 12: PCC / CH2Cl2 / 15 h / 25 °C 13: 82 percent / K2CO3 / methanol / 36 h / 25 °C 14: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 15: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 16: NaBH4 View Scheme

1: 95 percent / (NH4)2Ce(NO3)6 / acetonitrile; H2O / 0.25 h / 25 °C 2: K2CO3 / dimethylformamide 3: aq. Na2S2O4 4: K2CO3 / acetone / 6 h / Heating 5: aq. KOH / ethanol / 10 h / 25 °C 6: PPE / CHCl3 / 36 h / 25 °C 7: aq. KOH / ethanol / 8 h / 25 °C 9: PCC / CH2Cl2 / 15 h / 25 °C 10: 82 percent / K2CO3 / methanol / 36 h / 25 °C 11: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 12: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 13: NaBH4 View Scheme

1: 80 percent / NaBH4, K2CO3 / methanol / 0.5 h / 25 °C 2: 95 percent / (NH4)2Ce(NO3)6 / acetonitrile; H2O / 0.25 h / 25 °C 3: K2CO3 / dimethylformamide 4: aq. Na2S2O4 5: K2CO3 / acetone / 6 h / Heating 6: aq. KOH / ethanol / 10 h / 25 °C 7: PPE / CHCl3 / 36 h / 25 °C 8: aq. KOH / ethanol / 8 h / 25 °C 10: PCC / CH2Cl2 / 15 h / 25 °C 11: 82 percent / K2CO3 / methanol / 36 h / 25 °C 12: 95 percent / ceric ammonium nitrate / acetonitrile; H2O 13: 85 percent / Et3N*BCl3 / CH2Cl2 / 0.25 h / 0 °C 14: NaBH4 View Scheme