2,3,4,6-四-O-苯甲酰基-α-D-吡喃甘露糖基三氯乙酰亚胺酯

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A solution of the alcohol 50 (424 mg, 0.401 mmol) and 2,3,4,6-tetra-O-benzoyl-α-D-mannopyranosyl trichloroacetimidate (357 mg, 0.481 mmol, 1.2 eq) in anhydrous DCM (7.5 mL) was stirred with powdered molecular sieves 3 Å (50 mg) at 0° C. for 1 h. A solution of TMSOTf (15 μL, 0.0802 mmol, 0.2 eq) in DCM (0.5 mL) was added dropwise via a syringe. The mixture was stirred at 0° C. for 2 h and TLC indicated complete conversion. Et3N (100 μL) was added. Pyridine (65 μL, 0.802 mmol) and benzoyl chloride (47 μL, 0.401 mmol) were added. The mixture was stirred at room temperature o/n and evaporated onto silica gel. Purification by column chromatography (silica 2.5×17 cm, gradient elution with hexane-EtOAc 210:30, 200:50, 180:60, 160:80 and 150:100) gave the trisaccharide 51 as a colourless gum (392 mg, 60%). 1H NMR (CDCl3, 400 MHz) δ 8.19-7.89 (m, 16H, Ph), 7.68-7.63 (m, 4H, Ph), 7.61-7.15 (m, 35H, Ph), 6.00 (dd or t, 1H, JH3-H4=10.7, JH4-H5=9.8, H4), 5.98 (dd or t, 1H, JH3-H4=9.8, J=9.8, H4), 5.92 (dd or t, 1H, J=10.7, J=9.8, H4), 5.72 (dd, 1H, JH1-H2=2.0, JH2-H3=3.9, H2), 5.56 (dd, 1H, JH2-H3=2.9, H3), 5.33 (d, 1H, J=2.0, H1), 5.26 (dd, 1H, J=2.0, H2), 5.19 (d, 1H, J=2.0, J=3.9, H2), 5.16 (d, 1H, J=2.0, H1), 4.90 (d, 1H, H1), 4.78 and 4.62 (AB quartet, 2H, Jgem=11.7, CH2), 4.65-4.56 (m, 3H), 4.45 (dd, 1H, Jgem=12.7, JH5-H6=3.9, H6), 4.35 (dd, 1H, H3), 4.34-4.28 (m, 2H), 4.24 (dd, 1H, J=12.7, JH5-H6=2.9, H6), 4.10 (dt or dm, 1H, H5), 4.01 (dd, 1H, J=12.7, H6), 3.95 (dd, 1H, JH5-H6=2.0, H6). The mixture was stirred at room temperature o/n and evaporated onto silica gel Purification by column chromatography (silica 2.5×17 cm, gradient elution with hexane-EtOAc 210:30, 200:50, 180:60, 160:80 and 150:100)

反应条件: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: In a 100 mL round bottom flask was added 2-azidoethyl 2,3,4-tri-O-benzoyl-α-D-mannopyranoside (720 mg, 1.282 mmol), 2,3,4,6-tetra-O-benzoyl-1-O-(2,2,2-trichloroethanimidoyl)-α-D-mannopyranose (1.14 g, 1.539 mmol) and 4 Å molecular sieves (300 mg). To the above mixture was added CH2Cl2 (10 mL). The reaction mixture was cooled to -78° C. To the above mixture was added TMSOTf (23.2 μL, 0.128 mmol). The mixture was allowed to gradually warm to 0° C. and stirred for 30 min. The reaction was then quenched with sat. NaHCO3, and the mixture was filtered through a pad of Celite. The filtrate was diluted with CH2Cl2 (20 mL), washed with brine and water. The organic phase was dried over MgSO4, filtered and concentrated. The residue was purified by flash chromatography on silica gel (80 g), eluting with 0-100% EtOAc in hexanes, to give the title product. LC-MS Method A: m/e=1157.64 [M+18] and 1163.52 [M+Na]; Rt=3.01 min. 1H NMR (CDCl3) δ 7.2-8.3 (m, 25H), 6.0 (t, 1H), 5.8 (t, 1H), 5.7 (m, 2H), 5.4 (s, 1H), 5.38 (m, 1H), 5.2 (s, 1H), 4.7 (dd, 1H), 4.6 (dd, 1H), 4.45 (m, 1H), 4.35 (dd, 1H), 3.9-4.0 (m, 2H), 3.8 (m, 2H), 3.7 (m, 1H), 3.4 (m, 2H). to gradually warm to 0° C. The reaction was then quenched with sat. NaHCO3 the mixture was filtered through a pad of Celite The filtrate was diluted with CH2Cl2 (20 mL) washed with brine and water The organic phase was dried over MgSO4 filtered concentrated The residue was purified by flash chromatography on silica gel (80 g) eluting with 0-100% EtOAc in hexanes

反应条件: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: In a 100 mL round bottom flask was added 2-azidoethyl 2,4-bis-O-benzoyl-6-O-trityl-α-D-mannopyranoside (400 mg, 0.572 mmol), 2,3,4,6-tetra-O-benzoyl-1-O-(2,2,2-trichloroethanimidoyl)-α-D-mannopyranose (508 mg, 0.686 mmol) and 4 Å molecular sieves (300 mg). To the above mixture was added CH2Cl2 (5 mL). The reaction mixture was cooled to −78° C., to which was added TMSOTf (10.33 μL, 0.057 mmol). The mixture was allowed to gradually warm to 0° C. and stirred for 30 min. The reaction was then quenched with sat'd NaHCO3, and filtered through a pad of Celite. The filtrate was diluted with CH2Cl2 (20 mL), washed with brine and water. The organic phase was dried over MgSO4, and concentrated. The residue was purified by flash chromatography on silica gel (80 g), eluting with 0-100% EtOAc in hexanes, to give the title product. LC-MS Method A: m/e=1278.80 [M+1]; Rt=3.14 min. 1H NMR (CDCl3) δ 7.1-8.3 (m, 30H), 6.0 (t, 1H), 5.8 (t, 1H), 5.7 (m, 2H), 5.4 (s, 1H), 5.38 (m, 1H), 5.2 (s, 1H), 4.7 (dd, 1H), 4.6 (dd, 1H), 4.45 (m, 1H), 4.35 (dd, 1H), 3.9-4.0 (m, 2H), 3.8 (m, 2H), 3.7 (m, 1H), 3.4 (m, 2H). to gradually warm to 0° C. The reaction was then quenched with sat'd NaHCO3 filtered through a pad of Celite The filtrate was diluted with CH2Cl2 (20 mL) washed with brine and water The organic phase was dried over MgSO4 concentrated The residue was purified by flash chromatography on silica gel (80 g) eluting with 0-100% EtOAc in hexanes