Reaktion #90566

Reaktionsgleichung

Trichloroacetonitrile

DBU

residue 211

3,4-Di-O-benzyl-2-O-levulinoyl-α-L-rhamnopyranose

→

212

Ausbeute 95.0%

3,4-Di-O-benzyl-2-O-levulinoyl-α-L-rhamnopyranosyl trichloroacetimidate

Ausbeute 95.0%

Lösungsmittel

DCM

Reaktionsbedingungen

Aufarbeitung

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

Vorschrift

Trichloroacetonitrile (1.3 mL, 13 mmol) and DBU (51 μL, 0.3 mmol) were added to a solution of the residue 211 (1.0 g, 2.3 mmol) in anhydrous DCM (6 mL) at 0° C. After 2 h, the mixture was concentrated. The residue was eluted from a column of silica gel with 3:1 cyclohexane-EtOAc and 0.2% Et3N to give 212 as a white foam (1.0 g, 95%); 1H NMR: δ 8.67 (s, 1H, NH), 7.40-7.30 (m, 10H, Ph), 6.19 (d, 1H, J1,2=1.9 Hz, H-1), 5.48 (dd, 1H, J1,2=2.0, J2,3=3.3 Hz, H-2), 4.95 (d, 1H, CH2Ph), 4.73 (d, 1H, CH2Ph), 4.66 (d, 1H, CH2Ph), 4.58 (d, 1H, CH2Ph), 4.51 (d, 1H, CH2Ph), 4.00 (dd, 1H, J3,4=9.5 Hz, H-3), 3.95 (dq, 1H, J4,5=9.6, J5,6=6.3 Hz, H-5), 3.52 (pt, 1H, H-4), 2.80 (m, 4H, Lev), 2.20 (s, 3H, Ac), 1.36 (d, 3H, H-6). Anal. Calcd for C27H30Cl3NO7.0.5H2O: C, 54.42; H, 5.24; N, 2.35. Found: C, 54.06; H, 5.06; 2.05.

Quelle