[NH:1]([C:9]([O:11][C:12]([CH3:15])([CH3:14])[CH3:13])=[O:10])[C@H:2]([CH2:7][OH:8])[CH2:3][CH2:4][CH2:5][CH3:6].[H-].[Na+].C1OCCOCCOCCOCCOCCOC1.Br[CH2:37][C:38]([O:40][CH2:41][CH3:42])=[O:39]>O1CCCC1>[C:12]([O:11][C:9]([NH:1][C@@H:2]([CH2:3][CH2:4][CH2:5][CH3:6])[CH2:7][O:8][CH2:37][C:38]([O:40][CH2:41][CH3:42])=[O:39])=[O:10])([CH3:14])([CH3:13])[CH3:15]To as stirred solution of Boc-L-Nle-ol (0.50 g, 1.9 mmol) in dry tetrahydrofuran (15 mL), cooled at 0° C. under nitrogen, NaH (0.05 g, 2.1 mmol) was added. The reaction mixture was stirred for 45 min at 0° C., followed by addition of 18-crown-6 (0.25 g, 0.9 mmol) and subsequently a solution of ethyl bromoacetate (0.47 g, 2.8 mmol) in dry tetrahydrofuran (4 mL) was added dropwise at 0° C. The reaction mixture was stirred for 1 h at 0° C. and overnight at room temperature. The organic solvent was evaporated under reduced pressure and the residue was purified by column-chromatography using chloroform as eluent. Yield 55%; Oil; [a]D=−13.9 (c 1CHCl3); 1H NMR (200 MHz, CDCl3) δ 4.85-4.78 (m, 1H), 4.17 (q, J=7.4 Hz, 2H), 4.03 (s, 2H), 3.72-3.58 (m, 1H), 3.56-3.41 (m, 2H), 1.62-1.21 (m, 18H), 0.85 (t, J=6.6 Hz, 3H); 13C NMR (50 MHz, CDCl3) δ 170.3, 155.6, 78.9, 73.3, 68.4, 60.7, 50.3, 31.5, 28.3, 28.1, 22.5, 14.1, 13.9. Anal. Calcd for C15H29NO5: C, 59.38; H, 9.63; N, 4.62. Found: C, 59.16; H, 9.82; N, 4.51.
불러오는 중…
