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

1: L-proline; N-chloro-succinimide / dichloromethane / 3 h / 0 - 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