7-Benzenesulfonyl-4-(1-benzyl-pyrrolidin-3-yl)-3,4-dihydro-2H-benzo[1,4]oxazine (0.127 g, 0.292 mmol) was dissolved in 15 mL ethanol and this solution was added to a flask containing 35 mg of 5% palladium on charcoal, followed by 3 drops of glacial acetic acid. The system was purged with hydrogen gas and stirring was continued for 24 hours under 1 atm. of hydrogen gas. The reaction mixture was filtered through celite, the filtrate concentrated in vacuo, and the resulting solid purified by flash (6:0.4:0.04 of CH2Cl2:MeOH:NH4OH) to give 45 mg of 7-benzenesulfonyl-4-pyrrolidin-3-yl-3,4-dihydro-2H-benzo[1,4]oxazine as free base. This solid was dissolved in 1 mL methanol and combined with 0.5 mL of 2N ethanolic hydrogen chloride and the resulting solution is concentrated in vacuo and subjected to a vacuum of 0.3 Torr for 2 hours to give a foam which was triturated twice with 50 mL ethyl ether to give, after drying under reduced pressure, 25 mg (0.07 mmol, 25%) of 7-benzenesulfonyl-4-pyrrolidin-3-yl-3,4-dihydro-2H-benzo[1,4]oxazine hydrochloride as a tan solid. MS: 345 (M+H)+, mp: 122.8-127.6° C.
