Sodium Carbonate → Fmoc-Thr(tBu)-Ser(tBu)-OBzl

Participants

Reaction Steps

To the CPME solution (35 mL) of H-Ser(tBu)-OBzl (2-OBzl(3,4,5-OPhy)-4-OMe) was added HOBt (71 mg, 0.43 mmol), Fmoc-Thr(tBu)-OH (1.00 g, 2.51 mmol), EDC.HCl (529 mg, 2.76 mmol) and DMF (10 ml) were added under ice-cooling, and the mixture was stirred at room temperature overnight. After completion of the reaction, to the reaction solution was added 20% brine (30 ml) to give an organic layer and an aqueous layer. While stirring the obtained organic layer and aqueous layer, 10% aqueous sodium carbonate solution was added dropwise until the pH of the aqueous layer became 6.0, and the organic layer and the aqueous layer were partitioned (hereinafter this operation is sometimes to be abbreviated as “pH=6.0 washing”). The pH-6.0 washing was further repeated twice. The solvent in the obtained organic layer was evaporated under reduced pressure, the residue was dissolved in cyclohexane (40 ml), and the mixture was washed four times with 80% by volume of aqueous acetonitrile solution (30 ml) with stirring, and the organic layer and the aqueous layer were partitioned. The obtained organic layer was dried over sodium sulfate and filtered. The solvent in the obtained filtrate was evaporated under reduced pressure to give Fmoc-Thr(tBu)-Ser(tBu)-OBzl (2-OBzl(3,4,5-OPhy)-4-OMe).

Provenance & Evidence