1,3-bis-(diphenylphosphino)propane; palladium diacetate; triethylamine in 1,4-dioxane T=100°C; P=7500.75 Torr; 16 h; Inert atmosphereAutoclave;

Amberlite IRA 900 resin in 1,4-dioxane T=85°C; 9 h;

tetra(n-butyl)ammonium hydrogensulfate; potassium carbonate in dichloromethane; water T=20°C;

(5aS,10bR)-5a,10b-dihydro-2-(2,4,6-trimethylphenyl)-4H,6H-indeno[2,1-b]-1,2,4-triazolo[4,3-d]-1,4-oxazinium chloride; triethylamine in ethyl acetate T=80°C; 4 h; Inert atmosphereMolecular sieve;

palladium diacetate; trifluoroacetic anhydride T=120°C; 16 h; regioselective reaction;

acetic anhydride T=150 - 160°C;

1: oxalyl dichloride / benzene / 24 h / 20 °C 2: potassium carbonate; tetra(n-butyl)ammonium hydrogensulfate / dichloromethane; water / 20 °C View Scheme

1.1: sodium hydride / dimethyl sulfoxide / 1 h / 0 °C / |Inert atmosphere 1.2: 3 h / 20 °C / |Inert atmosphere 2.1: hydrogenchloride / water; chloroform / 3 h / 20 °C / |Inert atmosphere 3.1: Dess-Martin periodane / dichloromethane / 1 h / 20 °C / |Inert atmosphere 4.1: triethylamine; (5aS,10bR)-5a,10b-dihydro-2-(2,4,6-trimethylphenyl)-4H,6H-indeno[2,1-b]-1,2,4-triazolo[4,3-d]-1,4-oxazinium chloride / ethyl acetate / 4 h / 80 °C / |Inert atmosphere; |Molecular sieve View Scheme

1: hydrogenchloride / water; chloroform / 3 h / 20 °C / |Inert atmosphere 2: Dess-Martin periodane / dichloromethane / 1 h / 20 °C / |Inert atmosphere 3: triethylamine; (5aS,10bR)-5a,10b-dihydro-2-(2,4,6-trimethylphenyl)-4H,6H-indeno[2,1-b]-1,2,4-triazolo[4,3-d]-1,4-oxazinium chloride / ethyl acetate / 4 h / 80 °C / |Inert atmosphere; |Molecular sieve View Scheme

1: Dess-Martin periodane / dichloromethane / 1 h / 20 °C / |Inert atmosphere 2: triethylamine; (5aS,10bR)-5a,10b-dihydro-2-(2,4,6-trimethylphenyl)-4H,6H-indeno[2,1-b]-1,2,4-triazolo[4,3-d]-1,4-oxazinium chloride / ethyl acetate / 4 h / 80 °C / |Inert atmosphere; |Molecular sieve View Scheme