zirconium tetrachloride in tetrahydrofuran T=70°C; 24 h; Molecular sieveInert atmosphere;

1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine T=75°C; 12 h;

1H-1,2,4-triazol; C6H10N3O2S(1+)*Cl(1-); N-ethyl-N,N-diisopropylamine in dichloromethane T=40°C; 12 h;

1: With pyridine; ruthenium trichloride; sodium hydride; 1,3-diisopropylimidazolium bromide in toluene 24 h; Inert atmosphereReflux; 2: in toluene

ethanol

chloral T=180°C;

1: dihydrogen peroxide; sodium hydroxide / methanol / 0.17 h / |Inert atmosphere; |Cooling with ice 2: dichloromethane / 6 h / 20 °C / |Inert atmosphere 3: sodium tris(acetoxy)borohydride / 1,2-dichloro-ethane / 16 h / |Inert atmosphere View Scheme

1: triethylamine / 16 h / 20 °C / |Inert atmosphere 2: N-ethyl-N,N-diisopropylamine; methanesulfonyl chloride / dichloromethane / 20 °C / |Inert atmosphere; |Cooling with ice 3: dihydrogen peroxide; sodium hydroxide / methanol / 0.17 h / |Inert atmosphere; |Cooling with ice 4: dichloromethane / 6 h / 20 °C / |Inert atmosphere 5: sodium tris(acetoxy)borohydride / 1,2-dichloro-ethane / 16 h / |Inert atmosphere View Scheme

in tetrahydrofuran; diethyl ether 4 h; Heating; Yield given;