Analogues of (1!6)-Branched (1!3)-Glucohexaose
459
129.0, 128.9, 128.7, 128.5, 128.4 (Bz-C), 102.6, 101.2, 89.5 (3C-1), 75.3, 73.4, 71.9, 71.5,
71.1, 69.8, 69.0, 68.9, 68.2, 68.1, 62.4, 61.9 (C-2–6), 20.9, 20.8 (2C, 2CH3CO).
Anal. Calcd for C78H68O26: C 65.92; H 4.79. Found: C 65.97; H 4.82.
2,3,4,6-Tetra-O-benzoyl-b-D-galactopyranosyl-(1 ! 3)-[2,3,4,6-tetra-O-benzoyl-
b-D-galactopyranosyl-(1!6)]-2,4-di-O-acetyl-a-D-glucopyranosyl
trichloroacetimidate (8)
Compound 7 (4.00 g, 2.84 mmol) was dissolved in CH2Cl2 (50 mL), then CCl3CN
(0.4 mL, 4.0 mmol) and K2CO3 (2.0 g, 14.0 mmol) were added. The reaction mixture
was stirred for 10 hr, at the end of which time TLC (2 : 1 petroleum ether–EtOAc) indi-
cated that the reaction was complete. The mixture was filtered, and the filtrate was concen-
trated. The residue was purified by flash chromatography (2 : 1 petroleum ether–EtOAc)
to give 8 (4.12 g, 93.1%) as a syrup: [a]D þ 2.58 (c 1.0, CHCl3); 1H NMR (CDCl3): d 8.38
(s, 1H, C55NH), 8.17–7.27 (m, 40H, 8Bz-H), 6.30 (d, 1H, J1,2 ¼ 3.6 Hz, H-1), 6.05 (d, 1H,
J3,4 ¼ 3.2 Hz, H-40), 6.00 (d, 1H, J3,4 ¼ 3.0 Hz, H-400), 5.84 (dd, 1H, J1,2 ¼ 7.9 Hz,
J2,3 ¼ 10.3 Hz, H-20), 5.73 (dd, 1H, J1,2 ¼ 7.9 Hz, J2,3 ¼ 10.8 Hz, H-200), 5.71–5.62
(m, 2H, H-30, H-300), 5.06–5.00 (m, 2H, H-10, H-100), 5.08 (dd, 1H, J3,4 ¼ J4,5 ¼ 9.6 Hz,
H-4), 4.78 (dd, 1H, J2,3 ¼ 9.6 Hz, H-2), 4.71 (dd, 1H, J6,6 ¼ 11.3 Hz, J5,6 ¼ 4.3 Hz,
H-60e), 4.62 (dd, 1H, J5,6 ¼ 4.2 Hz, J6,6 ¼ 11.0 Hz, H-600e), 4.53–3.80 (m, 7H, 4H-6,
3H-5), 4.28 (dd, 1H, J3,4 ¼ 9.6 Hz, H-3), 2.13, 1.86 (2s, 6H, 2MeCO); 13C NMR
(100 MHz, CDCl3): d 169.4, 169.2 (2C, 2CH3CO), 166.2, 166.1, 165.7, 165.6, 165.5,
165.4, 165.2 (8C, 8PhCO), 160.4 (1C, CNHCCl3), 133.9, 133.7, 133.6, 133.5, 133.4,
133.3, 130.1, 130.0, 129.9, 129.8, 129.6, 129.5, 129.4, 129.1, 129.0, 128.9, 128.7,
128.5, 128.4 (Bz-C), 101.2, 101.2, 92.8 (3C-1), 90.8 (1C, CNHCCl3), 76.1, 71.9, 71.6,
71.3, 69.8, 68.4, 68.2, 67.8, 62.2 (C-2–6), 20.9, 20.4 (2C, 2CH3CO).
Anal. Calcd for C80H68Cl3NO26: C 61.34; H 4.35. Found: C 61.62; H 4.51.
2,3,4,6-Tetra-O-benzoyl-b-D-galactopyranosyl-(1 ! 3)-[2,3,4,6-tetra-O-benzoyl-
b-D-glucopyranosyl-(1!6)]-1,2-O-isopropylidene-a-D-glucofuranose (10)
2,3,4,6-Tetra-O-benzoyl-b-D-glucopyranosyl trichloroacetimidate
5.30 mmol) and acceptor 4 (4.39 g, 5.50 mmol) were coupled as described in the general
9
(3.93 g,
procedure. Purification by chromatography with 3 : 1 petroleum ether–EtOAc as the
1
eluent gave trisaccharide 10 (6.63 g, 87.6%) as a syrup: [a]D 29.88 (c 1.0, CHCl3); H
NMR (CDCl3): d 8.07–7.27 (m, 40H, 8Bz-H), 6.01 (d, 1H, J3,4 ¼ 3.3 Hz, H-40), 5.90
(dd, 1H, J4,5 ¼ J3,4 ¼ 9.6 Hz, H-400), 5.78 (dd, 1H, J2,3 ¼ 9.8 Hz, H-20), 5.72 (dd, 1H,
J2,3 ¼ 9.9 Hz, H-200), 5.64 (dd, 1H, H-30), 5.58 (dd, 1H, H-300), 5.47 (d, 1H,
J1,2 ¼ 3.6 Hz, H-1), 4.96 (d, 1H, J1,2 ¼ 7.9 Hz, H-100), 4.94 (d, 1H, J1,2 ¼ 8.0 Hz, H-10),
4.70 (dd, 1H, J5,6 ¼ 3.1 Hz, J6,6 ¼ 12.2 Hz, H-60e), 4.54–4.13 (m, 10H, H-600, H-60a,
H-50, H-500, H-6, H-2, H-3, H-4), 3.87 (m, 1H, H-5), 1.32, 1.04 (2s, 6H, Me2C); 13C
NMR (100 MHz, CDCl3): d 165.7, 165.6, 165.4, 165.1, 165.0, 164.8, 164.7, 164.3 (8C,
8PhCO), 133.3, 133.2, 133.0, 132.8, 132.7, 129.6, 129.5, 129.4, 129.3, 129.2, 129.0,
128.6, 128.4, 128.3, 128.2, 128.1, 128.0, 127.8 (Bz-C), 111.7 (1C, Me2C), 104.5, 101.4,
101.2 (3C-1), 83.0, 82.7, 78.8, 72.6, 71.8, 71.6, 71.3, 71.0, 69.4, 69.3, 67.6, 67.3, 62.7,
61.6 (C-2–6), 26.2, 25.5 (2C, Me2C).
Anal. Calcd for C77H68O24: C 67.15; H 4.94. Found: C 67.26; H 4.99.