[CH:1]([OH:14])([CH:9]([OH:13])[C:10]([OH:12])=[O:11])[CH:2]([OH:8])[CH:3]([OH:7])[C:4]([OH:6])=[O:5].[NH3:15].N.COC(=N)CCCCCCC(=[NH:29])OC.[CH3:31][S:32][CH3:33].Cl>C([O-])(O)=O.[Na+].O>[CH:1]([OH:14])([CH:9]([OH:13])[C:10]([OH:12])=[O:11])[CH:2]([OH:8])[CH:3]([OH:7])[C:4]([OH:6])=[O:5].[NH3:29].[NH3:15].[CH3:31][S:32][CH3:33]
A 1.5 mL eppendorff tube was charged with a solution of 85.5 mg (0.233 mmol) of the bis(hydrochloride) salt of Example 3 (3) in 0.8 mL of 0.1 M NaHCO3. Dimethylsuberimidate.2HCl (DMS, Pierce Chemical Co., 63.6 mg, 0.233 mmol) was added and the solution was vortexed and centrifuged to dissolve the components. The resulting mixture was stirred at room temperature for 15 h. The mixture was then diluted to 8 mL with water and the pH was brought to 4 with the addition of 1 N HCl. This solution was then dialyzed with a 3500 MWCO dialysis membrane (Pierce pleated dialysis tubing) in ddH2O for 24 h. The dialyzed solution was lyophilized to dryness to give 49 mg of a white fluffy powder. 1H NMR (500 MHz, dDMSO) δ 9.15 (bs), 7.92 (bs), 5.43 (bs), 4.58 (bs), 4.17 (bs), 3.82 (bs), 3.37 (bs), 3.28 (bs), 2.82 (bs), 2.41 (bs), 1.61 (bs), 1.28 (bs). 13C NMR (126 MHz, dDMSO) δ 174.88 (s, 1H), 168.38 (s, 1H), 71.45 (s, 4H), 71.22 (s, 3H), 42.34 (s, 2H), 36.96 (s, 3H), 32.74 (s, 3H), 28.09 (s, 4H), 26.90 (s, 4H). Mw [GPC]=2520, Mw/Mn=1.15.
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