Lisa's Synthesis of Glycopeptide 1
Pentasaccharide glycosylamine 11(4 mg, 4.40 mmol) and L-pentapeptide 4837 (3.68 mg, 6.60 mmol) were mixed in anhydrous DMSO (0.5 mL) and HOBt (2.97 mg, 22 mmol), HBTU (9.48 mg, 22 mmol), and Hϋnig’s base (15 mL, 8.8 mmol) were added. After stirring for 2 d at room temperature, the reaction mixture was lyophilized and purified on a reverse-phase Vydac C18-column (4.6_250 mm) to afford 1 (2.5 mg, 1.72 mmol, 40%). HPLC gradient: A: 0.1% TFA/H2O, B: 0.09% TFA/70% CH3CN/H2O, gradient 5/50% B over 23 min; 50/100% B over 5 min; glycopeptide elutes at 21 min. 1H NMR (800 MHz, H2O, Watergate method, 24 _C): 8.52 (d,J¼8.9 Hz, 1H), 8.33 (d, J¼9.6 Hz, 1H), 8.33 (d, J¼7.3 Hz, 1H), 8.22 (d, J¼5.9 Hz, 1H), 8.12 (d, J¼8.2 Hz, 2H), 8.08 (d, J¼8.0 Hz, 1H), 7.92 (d, J¼8.0 Hz, 1H), 7.42 (s, 1H), 7.04 (s, 1H); (500 MHz, D2O, 30 _C) d¼5.24 (s, 1H, H-1c), 5.15 (d, J¼9.7 Hz, 1H, H-1a), 5.04 (s, 1H, H-1d), 4.90 (s, 1H, H-1d), 4.84 (t, J¼6.3 Hz, 1H), 4.76 (d, J¼12.6 Hz, 1H, H-1b), 4.33–4.48 (m, 22H), 4.19 (s, 1H), 3.70–4.10 (m, 18H), 3.00 (dd, J¼6.4, 16.4 Hz, 1H), 2.87 (dd, J¼6.4, 16.7 Hz, 1H), 2.30 (m, 1H), 2.20 (s, 3H, Ac), 2.15 (s, 3H, Ac), 2.13 (s, 3H, Ac), 1.76 (m, 1H), 1.50 (d, J¼7.2 Hz, 3H, CH3), 1.34 (d, J¼6.4 Hz, 3H, CH3), 1.07 (d, J¼6.5 Hz, 6H, 2CH3), 1.02 (d, J¼6.4 Hz, 3H, CH3); 13C (200 MHz, H2O, Watergate method, 24 _C): d¼105.2 (C-1), 104.2 (C-1), 103.3 (C-1), 102.5 (C-1), 81 (C-1a); HRMS (FAB) calcd for C58H99N9O33Na: 1472.6237, found: 1472.6282.
Pentasaccharide glycosylamine 11:
L-pentapeptide 4837:
Anhydrous:
If the DMSO is in water, the water will react with the reactants and the reaction will not
proceed as planned. So the DMSO must be anhydrous, or without water.
DMSO:
Dimethyl Sulfoxide
HOBt:
HBTU:
Hydroxybenzotriazole
Hϋnig's base:
N,N-Diisopropylethylamine, or Hünig's base, DIPEA or DIEA,
is an organic compound and an amine. It is used in organic chemistry as a base.
Lyophilized:
Freeze-dried
Purified:
Product was cleaned to remove any impurities from the solution, in this case,
a reverse phase Vydac C18-column was used.
Reverse-phase:
This is a form of column chromatography in which the compounds are sent through a column
with a non-polar stationary phase and an aqueous, slightly polar mobile phase.
Vydac C18-column:
The type of column used to run the reverse-phase column chromatography.
HPLC gradient:
High performance liquid chromatography.
TFA:
CH3CN:
Glycopeptide:
A peptide covalently bonded to a sugar or polysaccharide.
Elutes:
Materials extracted through column chromatography.
Watergate Method:
A method of removing solvent interference with molecules run through an NMR machine.
