C(N1C=CN=C1)(N1C=CN=C1)=O.[C:13]([O:17][C:18]([NH:20][CH2:21][CH2:22][CH2:23][CH2:24][C:25]1[CH:33]=[CH:32][C:28]([C:29]([OH:31])=O)=[CH:27][CH:26]=1)=[O:19])([CH3:16])([CH3:15])[CH3:14].[CH2:34]([CH2:36][NH2:37])[OH:35]>C1COCC1>[C:13]([O:17][C:18](=[O:19])[NH:20][CH2:21][CH2:22][CH2:23][CH2:24][C:25]1[CH:26]=[CH:27][C:28]([C:29](=[O:31])[NH:37][CH2:36][CH2:34][OH:35])=[CH:32][CH:33]=1)([CH3:14])([CH3:15])[CH3:16]1,1′-Carbonyldiimidazole (0.6 g, 3.71 mmol) was added into the solution of 26 (0.91 g, 3.09 mmol) in THF (50 mL). The reaction mixture was stirred at room temperature overnight under argon atmosphere, then ethanolamine (0.28 mL, 4.64 mmol) was added. The stirring was continued for 24 h at room temperature and argon atmosphere. The solvent was evaporated and the residue was purified by Flash™ (BIOTAGE, Inc) (90 g silica gel cartridge 40M, 18:1:0.1 chloroform/ethanol/concentrated ammonium hydroxide). 0.74 g (71%) of a white solid 27 was isolated. 1H NMR (300 MHz, CDCl3) δ 1.40 (s, 9H), 1.48 (m, 2H), 1.60 (m, 2H), 2.62 (m, 2H), 3.10 (m, 2H), 3.79 (m, 2H), 4.55 (br s, 1H), 6.74 (m, 1H), 7.18 (d, 2H), 7.66 (d, 2H).
Wird geladen…