phosphate buffer; thymidine phosphorylase pH=6.8; 24 h;

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;

1: 80 percent / trimethylsilyl trifluoromethanesulfonate; triethylamine / toluene; CH2Cl2 / 0.17 h / 20 °C 2: 86 percent / methylamine / methanol / 3 h / 20 °C 3: trifluoromethanesulfonic anhydride; 4-(dimethylamino)pyridine / CH2Cl2 / 2 h / 20 °C 4: 1.1 g / LiBr; BF3*OEt2 / dioxane; diethyl ether / 0.5 h / 50 °C 5: 94 percent / 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile); tributyltin hydride / CH2Cl2 / 0.25 h / 20 °C 6: 96 percent / tetrabutylammonium fluoride; acetic acid / tetrahydrofuran / 1.5 h / 0 °C View Scheme

1: N-iodosuccinimide / acetonitrile / 4 h 2: 88 percent / BCl3 / CH2Cl2 / 4 h / -78 °C View Scheme

tris-(dibenzylideneacetone)dipalladium(0); potassium carbonate; tris-(o-tolyl)phosphine; copper(l) chloride in N,N-dimethyl-formamide T=80°C; 0.0833333 h; Inert atmosphere;

1: trifluoromethanesulfonic anhydride; 4-(dimethylamino)pyridine / CH2Cl2 / 2 h / 20 °C 2: 1.1 g / LiBr; BF3*OEt2 / dioxane; diethyl ether / 0.5 h / 50 °C 3: 94 percent / 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile); tributyltin hydride / CH2Cl2 / 0.25 h / 20 °C 4: 96 percent / tetrabutylammonium fluoride; acetic acid / tetrahydrofuran / 1.5 h / 0 °C View Scheme

1: 86 percent / methylamine / methanol / 3 h / 20 °C 2: trifluoromethanesulfonic anhydride; 4-(dimethylamino)pyridine / CH2Cl2 / 2 h / 20 °C 3: 1.1 g / LiBr; BF3*OEt2 / dioxane; diethyl ether / 0.5 h / 50 °C 4: 94 percent / 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile); tributyltin hydride / CH2Cl2 / 0.25 h / 20 °C 5: 96 percent / tetrabutylammonium fluoride; acetic acid / tetrahydrofuran / 1.5 h / 0 °C View Scheme

1: 1.1 g / LiBr; BF3*OEt2 / dioxane; diethyl ether / 0.5 h / 50 °C 2: 94 percent / 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile); tributyltin hydride / CH2Cl2 / 0.25 h / 20 °C 3: 96 percent / tetrabutylammonium fluoride; acetic acid / tetrahydrofuran / 1.5 h / 0 °C View Scheme

1: 94 percent / 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile); tributyltin hydride / CH2Cl2 / 0.25 h / 20 °C 2: 96 percent / tetrabutylammonium fluoride; acetic acid / tetrahydrofuran / 1.5 h / 0 °C View Scheme

1: 90 percent / Bu4NF / tetrahydrofuran; acetonitrile / Ambient temperature 2: 91 percent / K2CO3 / methanol / 0.25 h / Ambient temperature View Scheme