Table 2.
Effects of the N-terminal amino acid residue on efficiency and epimerization
| Coupling of Fmoc-Ser(Ac3GalNAcα)OH to X-Gly-Hex-Resin, where X = |
||||||||
|---|---|---|---|---|---|---|---|---|
| Pro | Ser(Trt) | Leu | Ser(Ac3GalNAcα) | |||||
| #a | Yields (%)b | D/(D+L) (%)b | Yields (%)b | D/(D+L) (%)b | Yields (%)b | D/(D+L) (%)b | Yields (%)b | D/(D+L) (%)b |
| 1 | 69.1 | 5.1 | 99.0 | 2.6 | 97.7 | 3.8 | 92.5 | 3.9 |
| 2 | 74.6 | 11.4 | 99.6 | 6.7 | 98.0 | 7.1 | 91.5 | 6.6 |
| 3 | 99.8 | 0.8 | 99.6 | 1.3 | 98.3 | 2.3 | 99.1 | 1.9 |
| 4 | 99.4 | 69.8 | 99.9 | 71.7 | 98.5 | 69.3 | 99.2 | 70.8 |
| 5 | 99.4 | 5.2 | 99.4 | 3.6 | 98.3 | 4.4 | 96.1 | 3.9 |
| 6 | 99.3 | 9.7 | 99.8 | 4.3 | 97.4 | 2.9 | 97.8 | 3.0 |
| 7 | 99.7 | 1.9 | 99.1 | 1.0 | 98.4 | 1.7 | 95.4 | 3.8 |
| 8 | 87.1 | 10.1 | 99.8 | 3.0 | 98.2 | 4.2 | 96.9 | 3.8 |
| 9 | 88.1 | 2.1 | 99.7 | 2.1 | 98.1 | 2.6 | 96.2 | 5.7 |
| 10 | 99.9 | 5.2 | 99.6 | 1.4 | 98.1 | 2.7 | 96.9 | 4.9 |
| 11 | 99.7 | 2.9 | 99.8 | 1.0 | 98.2 | 2.1 | 97.2 | 3.3 |
| 12 | 98.4 | 3.0 | 99.8 | 0.8 | 98.5 | 1.6 | 96.9 | 3.2 |
| 13 | 99.1 | 1.1 | 98.3 | 0.2 | 99.3 | 1.5 | 96.8 | 0.5 |
a
Entry number corresponds to the coupling conditions listed in Table 1.
b
All yield and epimerization data have an error of less than 0.3%.