[S:1]([OH:5])([OH:4])(=[O:3])=[O:2].[C:6]([N:9]1[CH2:14][CH2:13][NH:12][CH2:11][CH2:10]1)(=[NH:8])[NH2:7].[C:15]([N:18]1[CH2:23][CH2:22][NH:21][CH2:20][CH2:19]1)(=[NH:17])[NH2:16].[C:24](O[C:32]([O:34][C:35]([CH3:38])([CH3:37])[CH3:36])=[O:33])([O:26][C:27]([CH3:30])([CH3:29])[CH3:28])=[O:25]>O1CCCC1.O>[S:1]([OH:5])([OH:4])(=[O:3])=[O:2].[C:6]([N:9]1[CH2:14][CH2:13][N:12]([C:24]([O:26][C:27]([CH3:30])([CH3:29])[CH3:28])=[O:25])[CH2:11][CH2:10]1)(=[NH:7])[NH2:8].[C:15]([N:18]1[CH2:23][CH2:22][N:21]([C:32]([O:34][C:35]([CH3:36])([CH3:37])[CH3:38])=[O:33])[CH2:20][CH2:19]1)(=[NH:16])[NH2:17]2.50 g of 1-amidinopiperazine hemisulfate were dissolved in 60 ml of a 1:1 by volume mixture of tetrahydrofuran and water, and a solution of 3.40 g of di-t-butyl dicarbonate in 10 ml of tetrahydrofuran was added to the resulting solution, after which the mixture was stirred at room temperature for 2.5 hours. At the end of this time, the tetrahydrofuran was removed from the reaction mixture by distillation under reduced pressure, the insolubles were filtered off and the filtrate was evaporated to dryness under reduced pressure. The resulting residue was extracted with ethanol (twice, each time with 50 ml) and methanol (twice, each time with 50 ml). The extract was evaporated to dryness to obtain 2.48 g of the title compound, as crystals, melting at 278° C. (with decomposition).
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