4-Methoxyphenyl-3-O-allyl-2,4,6-tri-O-benzyl-b-D-galactopyranoside → 4-Methoxyphenyl 2,4,6-tri-O-benzyl-beta-D-galactopyranoside

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Reaction Steps

Compound 9 (2.67 g, 4.49 mmol) was dissolved in a mixture of anhydrous methanol and toluene (21 mL, v/v 3:1) and reacted with PdCl2 (˜100 mg) under nitrogen and at room temperature. After 4 hours of reaction, the reaction mixture was filtrated over a pad of Celite and the solvents were evaporated. Purification of the residue by chromatography on silica gel (ethyl acetate-petroleum ether, v/v 1:4) afforded 10 as white crystals in 94% yield (2.35 g). mp=84-86° C.; [αD]24 =−11° (c 1, CHCl3); 1H NMR (500 MHz, CDCl3): δ3.66-3.73 (m, 3H, H-5, H-6a and H-6b), 3.74 (t, 1H, J2,3 9.5 Hz, J3,4 2.9 Hz, H-3), 3.76 (s, 3H, OMe), 3.83 (dd, 1H, J1,2 7.7 Hz, H-2), 3.90 (d, 1H, J4,5<1.5 Hz, H-4), 4.44, 4.49, 4.66, 4.78, 4.81 and 5.05 (6 d, 1H each, JA,B 11.8 Hz, CH2Ph), 4.84 (d, 1H, H-1), 6.78 and 7.02 (2 d, 2H each, C6H4), 7.22-7.40 (m, 15H, 3C6H5). Anal. Calcd for C34H36O7 (556.7): C 73.36, H 6.52; found: C 72.96, H 6.63.

Provenance & Evidence