M.S. Schmidt et al./Carbohydrate Research 425 (2016) 28–34
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2.3.1. Dimer 10
2.3.6. Heptamer (supposed HPLC peak)
Retention time (RP-HPLC, 10–90% B in A in 12 min): 4.49 min;
retention time (RP-HPLC, 20–55% B in A in 15 min): 4.47 min; 1H-
NMR (400.1 MHz, CDCl3): δ = 7.66 (s, 1 H, triazole-H), 5.93 (d, J = 9.4,
1H, NH), 5.69 (d, J = 9.5, 1H, NH), 5.30 - 5.10 (m, 3 H, H-3, H-3’, H-4’),
4.91 (‘t’, J = 9.2, 1H, H-4), 4.90 (d, J = 3.2, 1H, H-1’), 4.85 (m, 1H, CH2),
4.68 (d, J = 3.5, 1H, H-1), 4.67 (m, 1H, CH2), 4.61 (dd, J = 14.5, 2.7,
1H, H-6a), 4.38 (dd, J = 14.5, 8.5, 1H, H-6b), 4.36-4,27 (m, 2H, H-2,
H-2’), 4.24 (dd, J = 12.1, 4.4, 1 H, H-6a’), 4.16 (ddd, J = 10.1, 8.4, 2.5,
1H, H-5), 4.10 (dd, J = 12.3, 2.5, 1H, H-6b’), 4.03 (ddd, J = 9.5, 4.2. 2.4,
1H, H-5’), 3.14 (s, 3H, OCH3), 2.10 (s, 3H, C(O)CH3), 2.09 (s, 3H,
C(O)CH3), 2.08 (s, 3H, C(O)CH3), 2.01 (s, 3H, C(O)CH3), 1.99 (s, 3H,
C(O)CH3), 1.94 (s, 3H, C(O)CH3), 1.92 (s, 3H, C(O)CH3);
13C-NMR (100.6 MHz, CDCl3): δ = 171.2 (C(O)CH3), 171.1 (C(O)CH3),
170.7 (C(O)CH3), 170.2 (C(O)CH3), 170.0 (C(O)CH3), 169.9 (C(O)CH3),
169.2 (C(O)CH3), 143.3 (quaternary triazole C), 124.5 (triazole CH),
98.1 (C-1), 96.7 (C-1’), 71.2 and 70.9 (2C, C-3, C-3’), 69,6 (C-4), 68.2
(2C, C-5, C-5’), 68.1 (C-4’), 62.0 (C-6’), 60.9 (CH2), 55.4 (OCH3), 51.9
and 51.7 (2C, C-2, C-2’), 50.9 (C-6), 23.1 (CH3), 23.0 (CH3), 22.1 (CH3),
20.7 (CH3), 20.7 (CH3), 20.6 (CH3), 20.5 (CH3);
Retention time (RP-HPLC, 10–90% B in A in 12 min): 5.26 min;
retention time (RP-HPLC, 20–55% B in A in 15 min): 8.35 min.
2.3.7. Octamer (supposed HPLC peak)
Retention time (RP-HPLC, 20–55% B in A in 15 min): 8.66 min.
2.4. General procedure for the synthesis of linear triazole linked
pseudo oligosaccharides with ferrocene as analytical probe
Azido sugar 4 (0.385 mmol), ethynylferrocene 8 (0.385 mmol)
and azidopropargyl sugar 7 (different amounts, see Table 2) were
dissolved in 10 mL of a 10:10:3 mixture of DCM, MeOH and H2O.
CuSO4 (0.019 mmol), sodium ascorbate (0.096 mmol) and TBTA
(7 μmol) were added. The mixture was stirred at 60 °C. After one
hour the mixture was diluted with H2O (50 mL) and then ex-
tracted three times with DCM (3 × 40 mL). The organic layer was
washed with a sat. NaHCO3 solution and brine were dried (Na2SO4)
and the solvent was evaporated. Purification by flash chromatog-
raphy (EtOAc to EtOAc/MeOH 10:1) yielded the different fractions
of oligomeres and mixtures (see Table 2); some experiments were
analysed only by HPLC and ESI-MS.
(ESI-MS): m/z [M + H]+: 730.18;
Anal. Calcd for C30H43N5O16: C, 49.38; H, 5.94; N, 9.60; Found:
C, 49.19; H, 6.05; N, 9.24;
2.4.1. Fe-monomer 11
2.3.2. Trimer 12
Retention time (RP-HPLC, 10–90% B in A in 12 min): 4.84 min;
retention time (RP-HPLC, 15–35% B in A in 15 min): 9.87 min.
1H-NMR (400.1 MHz, DMSO-d6): δ = 8.13 (s, 1 H, triazole-H), 7.75
(d, J = 8.2, 1H, NH), 5.48 (d, J = 5.8, 1H, 3-OH), 4.89 (d, J = 5.9, 1H,
4-OH), 4.75 (m, 1 H, H-6a), 4.74 (m, 2H, Cp-H), 4.55 (d, J = 3.4, 1 H,
H-1), 4.41 (dd, J = 14.2, 9.1, 1H, H-6b), 4.29 (m, 2H, Cp-H), 4.00 (s,
5H, Cp-H), 3.72 (m, 2H, H-2, H-4), 3.48 (m, 1H, H-3), 3.11 (ddd,
J = 14.4, 8.9, 5.8, 1H, H-5), 3.00 (s, 3 H, OCH3), 1.82 (s, 3H, C(O)CH3).
13C-NMR (100.6 MHz, CDCl3): δ = 169.4 (C(O)CH3), 145.1 (qua-
ternary triazole C), 121.4 (triazole CH), 97.9 (C-1), 72.2 (C-5), 70.6
(C-3), 70.5 (C-4), 69.1 (Cp-Cs), 68.1 (Cp-Cs), 66.2 (Cp-C), 55.5 (OCH3),
54.0 (C-2), 50.9 (C-6), 22.5 (CH3).
Retention time (RP-HPLC, 10–90% B in A in 12 min): 4.79 min;
retention time (RP-HPLC, 20–55% B in A in 15 min): 5.84 min; 1H-
NMR (400.1 MHz, CDCl3): δ = 7.73 (s, 1 H, triazole-H), 7.64 (s, 1 H,
triazole-H), 6.33 (d, J = 9.4, 1H, NH), 5.99 (d, J = 9.4, 1H, NH), 5.75
(d, J = 9.5, 1H, NH), 5.37-5.19 (m, 3H, H-3, H-3’, H-3’’), 5.13 (‘t’, = 9.8,
1H, H-4’’), 4.98 - 4.85 (m, 4H, H-1’, H-1’’, H-4, H-4’), 4.82 (m, 1H,
CH2), 4.74 (d, J = 3.7, 1H, H-1), 4.70 (m, 1H, CH2), 4.62 (m, 2H, H-6a,
H-6a’), 4.46-4,24 (m, 6H, H-2, H-2’, H-2’’, H-5, H-6b, H-6b’), 4.21 (dd,
J = 12.4, 4.5, 1H, H-6a’’), 4.15 (ddd, J = 10.3, 8.3, 2.4, 1H, H-5’), 4.09
(dd, J = 12.7, 2.4, 1H, H-6b’’), 4.02 (ddd, J = 9.9, 4.1. 2.5, 1H, H-5’’),
3.15 (s, 3H, OCH3), 2.08 (s, 3H, C(O)CH3), 2.08 (s, 3H, C(O)CH3), 2.07
(s, 3H, C(O)CH3), 2.04 (s, 3H, C(O)CH3), 1.99 (s, 3H, C(O)CH3), 1.98
(s, 3H, C(O)CH3), 1.98 (s, 3H, C(O)CH3), 1.96 (s, 3H, C(O)CH3) 1.92 (s,
3H, C(O)CH3) 1.91 (s, 3H, C(O)CH3).
(ESI-MS): m/z [M + H]+: 471.05.
2.4.2. Fe-dimer 13
13C-NMR (100.6 MHz, CDCl3): δ = 171.3 (C(O)CH3), 171.2 (C(O)CH3),
171.1 (C(O)CH3), 171.1 (C(O)CH3), 170.8 (C(O)CH3), 170.5 (C(O)CH3),
170.4 (C(O)CH3), 170.1 (C(O)CH3), 169.7 (C(O)CH3), 169.4 (C(O)CH3),
143.5 (quaternary triazole C), 143.1 (quaternary triazole C), 124.6
(triazole CH), 124.5 (triazole CH), 98.1 (C-1), 96.7 (C-1’), 96.6 (C-
1’’), 71.1, 70.9 and 70.8 (3C, C-3, C-3’, C-3’’), 69,7 and 69.5 (2C, C-4,
C-4’), 68.5, 68.1 and 68.0 (3C, C-5, C-5’, C-5’’), 68.3 (C-4’’), 62.0 (C-
6’’), 61.0 (CH2), 60.9 (CH2), 55.5 (OCH3), 51.9, 51.7 and 51.6 (2C, C-2,
C-2’, C-2’’), 50.9 (C-6), 23.1 (CH3), 23.0 (2C, 2 x CH3), 20.8-20.5 (7C,
7 x CH3).
Retention time (RP-HPLC, 10–90% B in A in 12 min): 4.30 min;
retention time (RP-HPLC, 15–35% B in A in 15 min): 7.85 min.
3C-NMR (100.6 MHz, CDCl3): δ = 169.5 (C(O)CH3), 169.4 (C(O)CH3),
145.2 (quaternary triazole C), 142.9 (quaternary triazole C), 125.0
(triazole CH), 121.3 (triazole CH), 97.9 (C-1a), 95.7 (C-1b), 76.0-
50.9 (carbohydrate ring Cs and Cp-Cs), 22.6 (CH3), 22.5 (CH3).
(ESI-MS): m/z [M + H]+: 755.15.
2.4.3. Fe-trimer (mass identified in mixture) 15
(ESI-MS): m/z [M + H]+: 1098.29.
Retention time (RP-HPLC, 10–90% B in A in 12 min): 4.06 min;
retention time (RP-HPLC, 15–35% B in A in 15 min): 6.69 min; (ESI-
MS): m/z [M + H]+: 1039.38.
2.3.3. Tetramer (mass identified in mixture) 14
Retention time (RP-HPLC, 10–90% B in A in 12 min): 4.97 min;
retention time (RP-HPLC, 20–55% B in A in 15 min): 6.78 min; (ESI-
MS): m/z [M + H]+: 1466.54.
2.4.4. Fe-tetramer (mass identified in mixture) 17
Retention time (RP-HPLC, B in A 10–90% in 12 min): 3.92 min;
retention time (RP-HPLC, 15–35% B in A in 15 min): 6.10 min; (ESI-
MS): m/z [M + H]+: 1323.45.
2.3.4. Pentamer (mass identified in mixture) 16
Retention time (RP-HPLC, 10–90% B in A in 12 min): 5.09 min;
retention time (RP-HPLC, 20–55% in 15 min): 7.43 min; (ESI-
MS): m/z [M + H]+: 1834.64.
2.4.5. Fe-pentamer (supposed HPLC peak)
Retention time (RP-HPLC, 10–90% B in A in 12 min): 3.83 min;
retention time (RP-HPLC, 15–35% in 15 min): 5.73 min.
2.3.5. Hexamer (supposed HPLC peak)
2.4.6. Fe-hexamer (supposed HPLC peak)
Retention time (RP-HPLC, 10–90% B in A in 12 min): 5.18 min;
retention time (RP-HPLC, 20–55% B in A in 15 min): 7.93 min.
Retention time (RP-HPLC, 10–90% B in A in 12 min): 3.76 min;
retention time (RP-HPLC, 15–35% in 15 min): 5.48 min.