water; sodium hydroxide in isopropyl alcohol T=20°C; 72 h;

iodine; isopentyl nitrite in tetrahydrofuran T=50 - 60°C;

copper dichloride in ethanol T=85°C; 5 h;

1: With sulfuric acid in water 3 h; Reflux; 2: With sodium hydroxide in water pH=4.5;

1: 79 percent / dimethylsulfoxide; dimethylformamide / 72 h / 20 °C 2: 57 percent / tert-butyl nitrite; diidodomethane / acetonitrile / 2.5 h / 80 °C 3: 48 percent / aq. NaOH / propan-2-ol / 72 h / 20 °C View Scheme

1: 57 percent / tert-butyl nitrite; diidodomethane / acetonitrile / 2.5 h / 80 °C 2: 48 percent / aq. NaOH / propan-2-ol / 72 h / 20 °C View Scheme

1.1: 86 percent / POCl3 / N,N-dimethyl-acetamide / 2 h / 120 °C 2.1: 68 percent / p-TsOH / tetrahydrofuran / 80 °C 3.1: n-BuLi; 2,2,6,6-tetramethylpiperidine / hexane; tetrahydrofuran / 0.5 h / -78 °C 3.2: Bu3SnCl / hexane; tetrahydrofuran / 1 h / -78 °C 3.3: 8.0 g / iodine / tetrahydrofuran / 24 h 4.1: 98 percent / CuCl2 / aq. ethanol / 5 h / 85 °C View Scheme

1.1: 68 percent / p-TsOH / tetrahydrofuran / 80 °C 2.1: n-BuLi; 2,2,6,6-tetramethylpiperidine / hexane; tetrahydrofuran / 0.5 h / -78 °C 2.2: Bu3SnCl / hexane; tetrahydrofuran / 1 h / -78 °C 2.3: 8.0 g / iodine / tetrahydrofuran / 24 h 3.1: 98 percent / CuCl2 / aq. ethanol / 5 h / 85 °C View Scheme

1.1: n-BuLi; 2,2,6,6-tetramethylpiperidine / hexane; tetrahydrofuran / 0.5 h / -78 °C 1.2: Bu3SnCl / hexane; tetrahydrofuran / 1 h / -78 °C 1.3: 8.0 g / iodine / tetrahydrofuran / 24 h 2.1: 98 percent / CuCl2 / aq. ethanol / 5 h / 85 °C View Scheme

1: 6-chloro-2-iodo-(9H)-purine With di-isopropyl azodicarboxylate; triphenylphosphine in tetrahydrofuran T=-50°C; 0.166667 h; 2: isopropyl alcohol in tetrahydrofuran T=20°C; 48 h;