[C:1]1([S:7]([C:10]2[CH:22]=[CH:21][C:13]3[N:14]([C:18](Cl)=[O:19])[CH2:15][CH2:16][O:17][C:12]=3[CH:11]=2)(=[O:9])=[O:8])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.C(=O)(O)O.[NH2:27][C:28]([NH2:30])=[NH:29].C(N(CC)C(C)C)(C)C>C(#N)C>[C:1]1([S:7]([C:10]2[CH:22]=[CH:21][C:13]3[N:14]([C:18]([NH:29][C:28]([NH2:30])=[NH:27])=[O:19])[CH2:15][CH2:16][O:17][C:12]=3[CH:11]=2)(=[O:9])=[O:8])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1To a suspension of 7-benzenesulfonyl-2,3-dihydro-benzo[1,4]oxazine-4-carbonyl chloride (0.360 g., 1 mmol) in 20 mL acetonitrile, was added guanidine carbonate (0.180 g., 1 mmol), followed by the dropwise addition of N,N-diisopropyl ethylamine (0.523 mL, 3 mmol.) The reaction mixture was partitioned between 50 mL each of water and ethyl acetate. The organic fraction was washed with dilute aqueous hydrogen chloride followed by 50 mL water. The organic fraction was dried over sodium sulfate and concentrated in vacuo. The resulting white solid was dissolved in 20 mL refluxing dichloromethane. On cooling, white crystals formed, which were filtered and dried under vacuum to give 73 mg (21 %) of N-(7-benzenesulfonyl-2,3-dihydro-benzo[1,4]oxazine-4-carbonyl)-guanidine free base, which recrystallized from EtOH/HCl/Et2O to provide the hydrochloride salt. MS: 361 (M+H)+, mp (as hydrochloride): 148.5-151.6° C.
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