Table 2.
Linkage-specific sialic acid derivatization
| (1st step) Linkage-specific derivatization | (2nd step) Lactone stabilization | |||||
|---|---|---|---|---|---|---|
| Nucleophile | Condensing reagents and reaction condition | Derivatives (α2,6-/α2,3-) | Reaction condition for lactones originating from α2,3- | Total reaction time for 2-step derivatization | Publication | Name |
| MeOH | DMT-MM, 80 ℃, 1 hour | Methylester/ Lactone | — | — | Wheeler et al., 200948) | |
| Ammonia | DMT-MM, 60 ℃, 15 hours | Amide/ Lactone | Solid-phase permethylation, room temp., 0.5 hour | Over 15 hours | Alley et al., 201049) | |
| EtOH | EDC+HOBt, 37 ℃, 1∼2 hours | Ethylester/ Lactone | — | — | Reiding et al., 201450) | |
| Lactone cleavage (pH 10, 1 hour) followed by methylamidation by PyAOP (room temp., 0.5 hour) | 2.5 hours | Li et al., 201654) | STSD | |||
| Amidation by p-toluidine, room temp., 3 hours | 5 hours | Yang et al., 201757) | ||||
| Amidation by ethylenediamine (EDA), 37 ℃, 3 hours | 5 hours | Yang et al., 201858) | ||||
| Amidation by EDC+HOBt, 60 ℃, 2 hours | 3 hours | Lageveen-Kammeijer and de Haan et al., 201960) | ||||
| Dimethylamine | EDC+HOBt in DMSO, 60 ℃, 1∼3 hours | Dimethylamide/ Lactone | — | — | de Haan et al., 201551) | |
| Amidation by EDC+HOBt, 60 ℃, 2 hours | 3 hours | Holst et al., 201655) | Double amidation | |||
| Permethylation | 2.5 hours | Jiang et al., 201756) | SSAP | |||
| Isopropylamine | EDC+HOBt in DMSO, room temp., 1∼2 hours | Isopropylamide/ Lactone | Methylamidation by PyAOP, room temp., 1 hour | 2 hours | Nishikaze et al., 201752) | SALSA |
| Aminolysis by methylamine or ethylamine, room temp., Few seconds | 1 hour | Hanamatsu et al., 201859) | Aminolysis-SALSA | |||
| Methylamidation by EDC+ HOBt, 60 ℃, 2 hours | 4 hours | Suzuki et al., 201869) | Modified-SALSA | |||