(4aS,8aR)-1,4,4a,5,6,7,8,8a-octahydroquinoxaline-2,3-dione

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (4aR,8aS)-Octahydro-2,3-quinoxalinedione (4.67 g, 27.8 mmol) was added portion wise to 1M LAH (111 mL, 111 mmol) in diethyl ether (30 mL). The reaction was allowed to heated to reflux and stirred at reflux for 4 h. After cooling to room temperature, the reaction was quenched by the sequential addition of H2O (4.2 mL), 15% NaOH (4.2 mL), and H2O (12.6 mL). The mixture was stirred for 0.5 h, and the solids were filtered off and washed with excess EtOAc. The combined filtrates were concentrated under reduced pressure to provide (4aR,8aS)-decahydroquinoxaline as a white solid (3.6 g, 92%). LCMS: (M+H)+: 141.1. to heated to reflux at reflux for 4 h the reaction was quenched by the sequential addition of H2O (4.2 mL), 15% NaOH (4.2 mL), and H2O (12.6 mL) The mixture was stirred for 0.5 h the solids were filtered off washed with excess EtOAc The combined filtrates were concentrated under reduced pressure

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of cis-1,2-diaminocyclohexane (4.8 g, 42 mmol) in dimethoxy ethylene (100 mL) was added slowly diethyl oxalate (28.5 mL, 210 mmol). The reaction mixture was stirred at room temperature for 0.5 h and at 100° C. for 2 h. After the suspension was cooled down to room temperature, the resulting white solid precipitate was collected by filtration. The precipitate was washed with diethyl ether and dried to yield (4aR,8aS)-octahydro-2,3-quinoxalinedione (4.6 g, 66%). LCMS: (M+H)+: 169.1. After the suspension was cooled down to room temperature the resulting white solid precipitate was collected by filtration The precipitate was washed with diethyl ether dried