potassium hydroxide in tetrahydrofuran T=60°C; 24 h;

formaldehyd; [3H]-Tetracycline; 1,1'-dimethyl-4,4'-bipyridinium dichloride in water T=37°C; 69 h; Clostridium formicoaceticum, phosphate buffer;

sodium hydroxide T=20°C; Hydrolysis; 18 h;

[3H]-Tetracycline in water T=37°C; 142 h; Clostridium formicoaceticum, phosphate buffer; Title compound not separated from byproducts;

hydrogenchloride 5 h; Heating;

1: 100 percent / diethyl phosphorocyanidate, TEA / dimethylformamide / 2 h / 0 °C 2: 98 percent / trifluoroacetic acid / CH2Cl2 / 3 h / Ambient temperature 3: 83 percent / N-iodosuccinimide / dimethylformamide / 12 h / 36 °C 4: 92 percent / n-Bu3SnH / benzene / 0.5 h / Heating 5: 100 percent / 6N aq. HCl / 5 h / Heating View Scheme

1: 96 percent / CrO3, 1.5 M H2SO4 / acetone 2: 100 percent / diethyl phosphorocyanidate, TEA / dimethylformamide / 2 h / 0 °C 3: 98 percent / trifluoroacetic acid / CH2Cl2 / 3 h / Ambient temperature 4: 83 percent / N-iodosuccinimide / dimethylformamide / 12 h / 36 °C 5: 92 percent / n-Bu3SnH / benzene / 0.5 h / Heating 6: 100 percent / 6N aq. HCl / 5 h / Heating View Scheme

1: 97 percent / tetrabutylammonium fluoride / tetrahydrofuran 2: 96 percent / CrO3, 1.5 M H2SO4 / acetone 3: 100 percent / diethyl phosphorocyanidate, TEA / dimethylformamide / 2 h / 0 °C 4: 98 percent / trifluoroacetic acid / CH2Cl2 / 3 h / Ambient temperature 5: 83 percent / N-iodosuccinimide / dimethylformamide / 12 h / 36 °C 6: 92 percent / n-Bu3SnH / benzene / 0.5 h / Heating 7: 100 percent / 6N aq. HCl / 5 h / Heating View Scheme

1: 83 percent / N-iodosuccinimide / dimethylformamide / 12 h / 36 °C 2: 92 percent / n-Bu3SnH / benzene / 0.5 h / Heating 3: 100 percent / 6N aq. HCl / 5 h / Heating View Scheme

1: 92 percent / n-Bu3SnH / benzene / 0.5 h / Heating 2: 100 percent / 6N aq. HCl / 5 h / Heating View Scheme