反応 #90568

反応方程式

hemiacetal

(3,4,6-tri-O-acetyl-2-deoxy-2-trichloroacetamido-β-D-glucopyranosyl)-(1→2)-3,4-di-O-benzyl-α-L-rhamnopyranose

Trichloroacetonitrile

DBU

→

306

収率 79.5%

(3,4,6-tri-O-acetyl-2-deoxy-2-trichloroacetamido-β-D-glucopyranosyl)-(1→2)-3,4-di-O-benzyl-α-L-rhamnopyranose trichloroacetimidate

収率 79.5%

溶媒

CH2Cl2

反応条件

後処理

1. 1
   濃縮The mixture was concentrated
2. 2
   洗浄The residue was eluted from a column of silica gel with 7:3 cyclohexane-EtOAc and 0.2% of Et3N

実験手順

The hemiacetal 318 (539 mg, 0.68 mmol) was dissolved in CH2Cl2 (50 mL), placed under argon and cooled to 0° C. Trichloroacetonitrile (0.6 mL, 6.8 mmol), then DBU (10 μL, 70 μmol) were added. The mixture was stirred at 0° C. for 30 min. The mixture was concentrated and toluene was co-evaporated from the residue. The residue was eluted from a column of silica gel with 7:3 cyclohexane-EtOAc and 0.2% of Et3N to give 306 (498 mg, 78%) as a colourless foam; [α]D−18° (c 1, CHCl3). 1H NMR: δ 8.48 (s, 1H, NH), 7.40-7.15 (m, 10H, Ph), 6.75 (d, 1H, J2,NH=8.5 Hz, NHD), 6.18 (d, 1H, J1,2=1.1 Hz, H-1A), 5.15 (pt, 1H, J2,3=J3,4=9.5 Hz, H-3D), 5.07 (pt, 1H, J4,5=9.5 Hz, H-4D), 4.82-4.50 (m, 4H, CH2Ph), 4.62 (d, 1H, J1,2=8.5 Hz, H-1D), 4.20-4.03 (m, 2H, J5,6=4.5, J6a,6b=12.3 Hz, H-6aD, 6bD), 3.98 (m, 1H, H-2D), 3.85 (dq, 1H, J4,5=9.5, J5,6=6.2 Hz, H-5A), 3.84 (dd, 1H, J2,3=3.3 Hz, H-2A), 3.83 (dd, 1H, J3,4=9.5 Hz, H-3A), 3.55 (m, 1H, H-5D), 3.45 (pt, 1H, H-4A), 1.98, 1.96, 1.93 (3s, 9H, OAc), 1.23 (d, 3H, H-6A); 13C NMR: δ 171.1, 170.0, 169.6, 162.1 (C═O), 138.4-127.2 (Ph), 101.7 (C-1D), 97.2 (C-1A), 92.6 (CCl3), 80.5 (C-4A), 79.1 (C-3A), 76.2 (C-2A), 76.2, 74.1 (2C, CH2Ph), 74.4 (C-3D), 74.1 (C-5D), 71.3 (C-5A), 68.6 (C-4D), 62.3 (C-6D), 56.3 (C-2D), 21.1, 21.0, 20.9 (3C, OAc), 18.2 (C-6A). Anal. Calcd for C36H40Cl6N2O13: C, 46.93; H, 4.38; N, 3.04%. Found: C, 46.93; H, 4.52; N, 2.85%.

出典