hydrogenchloride T=90.1°C; hydrolysis of uracil 4'-thio-2'-deoxynucleosides and its 5-substituted derivatives; competition between the acid-catalysed depyrimidination and isomerisation to a 5-thiopyranoside nucleosides; proposed mechanism; Rate constantProduct distribution;

sodium methylate in methanol 2.5 h; Ambient temperature;

boron trichloride in dichloromethane T=-80°C; 16 h;

boron tribromide in dichloromethane

potassium carbonate in methanol 0.25 h; Ambient temperature;

1: 45 percent / Et3N / CH2Cl2 / 16 h / Ambient temperature 2: 92 percent / NH3/MeOH / CH2Cl2 / 15 h / Ambient temperature 3: 97 percent / BCl3 / CH2Cl2 / 16 h / -80 °C View Scheme

1: 67 percent / acetic acid 2: 82 percent / CF3SO3SiMe3 / 1,2-dichloro-ethane / Ambient temperature 3: 40 percent / pyridine 4: 60 percent / BBr3 / CH2Cl2 View Scheme