iron; acetic acid 2 h;

trifluoroacetic acid

1: DMAP / tetrahydrofuran 2: NaOH / H2O; tetrahydrofuran; ethanol 3: NH2OH / H2O; ethanol / 1.5 h / Heating 4: i-Pr2NEt / CH2Cl2 / 0 °C 5: Bu4NF / tetrahydrofuran 6: 95 percent / TFA View Scheme

1: NH2OH / H2O; ethanol / 1.5 h / Heating 2: i-Pr2NEt / CH2Cl2 / 0 °C 3: Bu4NF / tetrahydrofuran 4: 95 percent / TFA View Scheme

1: i-Pr2NEt / CH2Cl2 / 0 °C 2: Bu4NF / tetrahydrofuran 3: 95 percent / TFA View Scheme

sodium ethanolate in ethanol 1.5 h; Reflux;

1: hydroxylamine hydrochloride / dimethyl sulfoxide / 3 h / 20 - 100 °C 2: hydroxylamine hydrochloride; sodium hydroxide / water; ethanol / 36 h / |Inert atmosphere; |Reflux 3: pyridine / 0.5 h / |Reflux; |Inert atmosphere 4: Na2S*9H2O / 1,4-dioxane; water / 0.75 h / 80 °C / |Inert atmosphere View Scheme

1: hydroxylamine hydrochloride; sodium hydroxide / water; ethanol / 36 h / |Inert atmosphere; |Reflux 2: pyridine / 0.5 h / |Reflux; |Inert atmosphere 3: Na2S*9H2O / 1,4-dioxane; water / 0.75 h / 80 °C / |Inert atmosphere View Scheme

1: pyridine / 0.5 h / |Reflux; |Inert atmosphere 2: Na2S*9H2O / 1,4-dioxane; water / 0.75 h / 80 °C / |Inert atmosphere View Scheme

1.1: triethylamine / potassium iodide / toluene / 24 h / boiling 2.1: sodium hydroxide / 20 °C 2.2: pH 5 3.1: 1-propanephosphonic acid cyclic anhydride / ethyl acetate / 2 h / 20 - 50 °C 4.1: hydrogen; acetic acid / 5 palladium on charcoal / ethanol / 24 h / 50 °C / 3750.38 Torr / Inert atmosphere 4.2: 20 °C 5.1: potassium carbonate / ethanol; water; acetone / 0.33 h / 28 - 32 °C View Scheme